Difference between revisions of "Kubernetes/the-hard-way"

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This article will show how to setup '''Kubernetes The Hard Way''', as originally developed by [https://github.com/kelseyhightower Kelsey Hightower]. I will add my own additions, changes, alterations, etc. to the process (and this will be continually expanded upon).
 
This article will show how to setup '''Kubernetes The Hard Way''', as originally developed by [https://github.com/kelseyhightower Kelsey Hightower]. I will add my own additions, changes, alterations, etc. to the process (and this will be continually expanded upon).
 +
 +
I will show you how to set up [[Kubernetes]] from scratch using [[Google Cloud Platform]] (GCP) VMs running Ubuntu 18.04.
 +
 +
I will use the latest version of Kubernetes (as of August 2019):
 +
<pre>
 +
$ curl -sSL https://dl.k8s.io/release/stable.txt
 +
v1.15.2
 +
</pre>
  
 
==Install the client tools==
 
==Install the client tools==
Line 578: Line 586:
  
 
Note: The <code>kube-proxy</code>, <code>kube-controller-manager</code>, <code>kube-scheduler</code>, and <code>kubelet</code> client certificates will be used to generate client authentication configuration files in the next section.
 
Note: The <code>kube-proxy</code>, <code>kube-controller-manager</code>, <code>kube-scheduler</code>, and <code>kubelet</code> client certificates will be used to generate client authentication configuration files in the next section.
 +
 +
==Generating Kubernetes Configuration Files for Authentication==
 +
 +
In this section, we will generate [https://kubernetes.io/docs/concepts/configuration/organize-cluster-access-kubeconfig/ Kubernetes configuration files], also known as kubeconfigs, which enable Kubernetes clients to locate and authenticate to the Kubernetes API Servers.
 +
 +
===Client Authentication Configs===
 +
 +
In this section, we will generate kubeconfig files for the <code>controller manager</code>, <code>kubelet</code>, <code>kube-proxy</code>, and <code>scheduler</code> clients and the admin user.
 +
 +
; Kubernetes Public IP Address
 +
 +
Each kubeconfig requires a Kubernetes API Server to connect to. To support high availability the IP address assigned to the external load balancer fronting the Kubernetes API Servers will be used.
 +
 +
* Retrieve the <code>kubernetes-the-hard-way</code> static IP address:
 +
<pre>
 +
KUBERNETES_PUBLIC_ADDRESS=$(gcloud compute addresses describe kubernetes-the-hard-way \
 +
  --region $(gcloud config get-value compute/region) \
 +
  --format 'value(address)')
 +
</pre>
 +
 +
; The kubelet Kubernetes Configuration File
 +
 +
When generating kubeconfig files for Kubelets the client certificate matching the Kubelet's node name must be used. This will ensure Kubelets are properly authorized by the Kubernetes [https://kubernetes.io/docs/admin/authorization/node/ Node Authorizer].
 +
 +
* Generate a kubeconfig file for each worker node:
 +
<pre>
 +
for instance in worker-0 worker-1 worker-2; do
 +
  kubectl config set-cluster kubernetes-the-hard-way \
 +
    --certificate-authority=ca.pem \
 +
    --embed-certs=true \
 +
    --server=https://${KUBERNETES_PUBLIC_ADDRESS}:6443 \
 +
    --kubeconfig=${instance}.kubeconfig
 +
 +
  kubectl config set-credentials system:node:${instance} \
 +
    --client-certificate=${instance}.pem \
 +
    --client-key=${instance}-key.pem \
 +
    --embed-certs=true \
 +
    --kubeconfig=${instance}.kubeconfig
 +
 +
  kubectl config set-context default \
 +
    --cluster=kubernetes-the-hard-way \
 +
    --user=system:node:${instance} \
 +
    --kubeconfig=${instance}.kubeconfig
 +
 +
  kubectl config use-context default --kubeconfig=${instance}.kubeconfig
 +
done
 +
</pre>
 +
 +
* Results:
 +
<pre>
 +
worker-0.kubeconfig
 +
worker-1.kubeconfig
 +
worker-2.kubeconfig
 +
</pre>
 +
 +
; The kube-proxy Kubernetes Configuration File
 +
 +
* Generate a kubeconfig file for the <code>kube-proxy</code> service:
 +
<pre>
 +
{
 +
  kubectl config set-cluster kubernetes-the-hard-way \
 +
    --certificate-authority=ca.pem \
 +
    --embed-certs=true \
 +
    --server=https://${KUBERNETES_PUBLIC_ADDRESS}:6443 \
 +
    --kubeconfig=kube-proxy.kubeconfig
 +
 +
  kubectl config set-credentials system:kube-proxy \
 +
    --client-certificate=kube-proxy.pem \
 +
    --client-key=kube-proxy-key.pem \
 +
    --embed-certs=true \
 +
    --kubeconfig=kube-proxy.kubeconfig
 +
 +
  kubectl config set-context default \
 +
    --cluster=kubernetes-the-hard-way \
 +
    --user=system:kube-proxy \
 +
    --kubeconfig=kube-proxy.kubeconfig
 +
 +
  kubectl config use-context default --kubeconfig=kube-proxy.kubeconfig
 +
}
 +
</pre>
 +
 +
* Results:
 +
<pre>
 +
kube-proxy.kubeconfig
 +
</pre>
 +
 +
; The kube-controller-manager Kubernetes Configuration File
 +
 +
* Generate a kubeconfig file for the <code>kube-controller-manager</code> service:
 +
<pre>
 +
{
 +
  kubectl config set-cluster kubernetes-the-hard-way \
 +
    --certificate-authority=ca.pem \
 +
    --embed-certs=true \
 +
    --server=https://127.0.0.1:6443 \
 +
    --kubeconfig=kube-controller-manager.kubeconfig
 +
 +
  kubectl config set-credentials system:kube-controller-manager \
 +
    --client-certificate=kube-controller-manager.pem \
 +
    --client-key=kube-controller-manager-key.pem \
 +
    --embed-certs=true \
 +
    --kubeconfig=kube-controller-manager.kubeconfig
 +
 +
  kubectl config set-context default \
 +
    --cluster=kubernetes-the-hard-way \
 +
    --user=system:kube-controller-manager \
 +
    --kubeconfig=kube-controller-manager.kubeconfig
 +
 +
  kubectl config use-context default --kubeconfig=kube-controller-manager.kubeconfig
 +
}
 +
</pre>
 +
 +
* Results:
 +
<pre>
 +
kube-controller-manager.kubeconfig
 +
</pre>
 +
 +
; The kube-scheduler Kubernetes Configuration File
 +
 +
* Generate a kubeconfig file for the <code>kube-scheduler</code> service:
 +
<pre>
 +
{
 +
  kubectl config set-cluster kubernetes-the-hard-way \
 +
    --certificate-authority=ca.pem \
 +
    --embed-certs=true \
 +
    --server=https://127.0.0.1:6443 \
 +
    --kubeconfig=kube-scheduler.kubeconfig
 +
 +
  kubectl config set-credentials system:kube-scheduler \
 +
    --client-certificate=kube-scheduler.pem \
 +
    --client-key=kube-scheduler-key.pem \
 +
    --embed-certs=true \
 +
    --kubeconfig=kube-scheduler.kubeconfig
 +
 +
  kubectl config set-context default \
 +
    --cluster=kubernetes-the-hard-way \
 +
    --user=system:kube-scheduler \
 +
    --kubeconfig=kube-scheduler.kubeconfig
 +
 +
  kubectl config use-context default --kubeconfig=kube-scheduler.kubeconfig
 +
}
 +
</pre>
 +
 +
* Results:
 +
<pre>
 +
kube-scheduler.kubeconfig
 +
</pre>
 +
 +
; The admin Kubernetes Configuration File
 +
 +
* Generate a kubeconfig file for the <code>admin</code> user:
 +
<pre>
 +
{
 +
  kubectl config set-cluster kubernetes-the-hard-way \
 +
    --certificate-authority=ca.pem \
 +
    --embed-certs=true \
 +
    --server=https://127.0.0.1:6443 \
 +
    --kubeconfig=admin.kubeconfig
 +
 +
  kubectl config set-credentials admin \
 +
    --client-certificate=admin.pem \
 +
    --client-key=admin-key.pem \
 +
    --embed-certs=true \
 +
    --kubeconfig=admin.kubeconfig
 +
 +
  kubectl config set-context default \
 +
    --cluster=kubernetes-the-hard-way \
 +
    --user=admin \
 +
    --kubeconfig=admin.kubeconfig
 +
 +
  kubectl config use-context default --kubeconfig=admin.kubeconfig
 +
}
 +
</pre>
 +
 +
* Results:
 +
<pre>
 +
admin.kubeconfig
 +
</pre>
 +
 +
===Distribute the Kubernetes Configuration Files===
 +
 +
* Copy the appropriate <code>kubelet</code> and <code>kube-proxy</code> kubeconfig files to each worker instance:
 +
<pre>
 +
for instance in worker-0 worker-1 worker-2; do
 +
  gcloud compute scp ${instance}.kubeconfig kube-proxy.kubeconfig ${instance}:~/
 +
done
 +
</pre>
 +
 +
* Copy the appropriate <code>kube-controller-manager</code> and <code>kube-scheduler</code> kubeconfig files to each controller instance:
 +
<pre>
 +
for instance in controller-0 controller-1 controller-2; do
 +
  gcloud compute scp admin.kubeconfig kube-controller-manager.kubeconfig kube-scheduler.kubeconfig ${instance}:~/
 +
done
 +
</pre>
  
 
==Generating the Data Encryption Config and Key==
 
==Generating the Data Encryption Config and Key==
Line 709: Line 911:
 
WantedBy=multi-user.target
 
WantedBy=multi-user.target
 
EOF
 
EOF
 +
</pre>
 +
 +
; Start the etcd Server
 +
<pre>
 +
{
 +
  sudo systemctl daemon-reload
 +
  sudo systemctl enable etcd
 +
  sudo systemctl start etcd
 +
}
 +
</pre>
 +
Remember to run the above commands on each controller node: <code>controller-0</code>, <code>controller-1</code>, and <code>controller-2</code>.
 +
 +
; Verification
 +
 +
* List the etcd cluster members:
 +
<pre>
 +
$ sudo ETCDCTL_API=3 etcdctl member list \
 +
  --endpoints=https://127.0.0.1:2379 \
 +
  --cacert=/etc/etcd/ca.pem \
 +
  --cert=/etc/etcd/kubernetes.pem \
 +
  --key=/etc/etcd/kubernetes-key.pem
 +
 +
3a57933972cb5131, started, controller-2, https://10.240.0.12:2380, https://10.240.0.12:2379
 +
f98dc20bce6225a0, started, controller-0, https://10.240.0.10:2380, https://10.240.0.10:2379
 +
ffed16798470cab5, started, controller-1, https://10.240.0.11:2380, https://10.240.0.11:2379
 +
</pre>
 +
 +
==Bootstrapping the Kubernetes Control Plane==
 +
 +
In this section, we will bootstrap the Kubernetes control plane across three compute instances and configure it for high availability. We will also create an external load balancer that exposes the Kubernetes API Servers to remote clients. The following components will be installed on each node: Kubernetes API Server, Scheduler, and Controller Manager.
 +
 +
; Prerequisites
 +
 +
The commands in this section must be run on each controller instance: <code>controller-0</code>, <code>controller-1</code>, and <code>controller-2</code>.
 +
 +
Using [[tmux]], split your shell into 3 x panes (<code>ctrl + b "</code>) and then log into each controller instance:
 +
<pre>
 +
$ gcloud compute ssh controller-0
 +
ctrl + b o
 +
$ gcloud compute ssh controller-1
 +
ctrl + b o
 +
$ gcloud compute ssh controller-2
 +
</pre>
 +
 +
Now, set tmux to run all subsequent commands (unless otherwise stated) in parallel on all 3 x controller instances (in all 3 x tmux panes):
 +
<pre>
 +
ctrl + b :
 +
set synchronize-panes on # off
 +
#~OR~
 +
setw synchronize-panes # toggles on/off
 +
</pre>
 +
 +
===Provision the Kubernetes Control Plane===
 +
 +
* Create the Kubernetes configuration directory:
 +
$ sudo mkdir -p /etc/kubernetes/config
 +
 +
; Download and Install the Kubernetes Controller Binaries
 +
 +
* Download the official Kubernetes release binaries:
 +
<pre>
 +
$ K8S_VERSION=$(curl -sSL https://dl.k8s.io/release/stable.txt)
 +
$ K8S_URL=https://storage.googleapis.com/kubernetes-release/release/${K8S_VERSION}/bin/linux/amd64
 +
$ wget -q --show-progress --https-only --timestamping \
 +
  "${K8S_URL}/kube-apiserver" \
 +
  "${K8S_URL}/kube-controller-manager" \
 +
  "${K8S_URL}/kube-scheduler" \
 +
  "${K8S_URL}/kubectl"
 +
</pre>
 +
 +
* Install the Kubernetes binaries:
 +
<pre>
 +
{
 +
  chmod +x kube-apiserver kube-controller-manager kube-scheduler kubectl
 +
  sudo mv kube-apiserver kube-controller-manager kube-scheduler kubectl /usr/local/bin/
 +
}
 +
</pre>
 +
 +
===Configure the Kubernetes API Server===
 +
 +
<pre>
 +
{
 +
  sudo mkdir -p /var/lib/kubernetes/
 +
 +
  sudo mv ca.pem ca-key.pem kubernetes-key.pem kubernetes.pem \
 +
    service-account-key.pem service-account.pem \
 +
    encryption-config.yaml /var/lib/kubernetes/
 +
 +
  sudo chmod 0600 /var/lib/kubernetes/encryption-config.yaml
 +
}
 +
</pre>
 +
 +
The instance internal IP address will be used to advertise the API Server to members of the cluster.
 +
 +
* Retrieve the internal IP address for the current compute instance:
 +
<pre>
 +
INTERNAL_IP=$(curl -s -H "Metadata-Flavor: Google" \
 +
  http://metadata.google.internal/computeMetadata/v1/instance/network-interfaces/0/ip)
 +
</pre>
 +
 +
* Create the <code>kube-apiserver.service</code> [[systemd]] unit file:
 +
<pre>
 +
cat <<EOF | sudo tee /etc/systemd/system/kube-apiserver.service
 +
[Unit]
 +
Description=Kubernetes API Server
 +
Documentation=https://github.com/kubernetes/kubernetes
 +
 +
[Service]
 +
ExecStart=/usr/local/bin/kube-apiserver \\
 +
  --advertise-address=${INTERNAL_IP} \\
 +
  --allow-privileged=true \\
 +
  --apiserver-count=3 \\
 +
  --audit-log-maxage=30 \\
 +
  --audit-log-maxbackup=3 \\
 +
  --audit-log-maxsize=100 \\
 +
  --audit-log-path=/var/log/audit.log \\
 +
  --authorization-mode=Node,RBAC \\
 +
  --bind-address=0.0.0.0 \\
 +
  --client-ca-file=/var/lib/kubernetes/ca.pem \\
 +
  --enable-admission-plugins=NamespaceLifecycle,NodeRestriction,LimitRanger,ServiceAccount,DefaultStorageClass,ResourceQuota \\
 +
  --etcd-cafile=/var/lib/kubernetes/ca.pem \\
 +
  --etcd-certfile=/var/lib/kubernetes/kubernetes.pem \\
 +
  --etcd-keyfile=/var/lib/kubernetes/kubernetes-key.pem \\
 +
  --etcd-servers=https://10.240.0.10:2379,https://10.240.0.11:2379,https://10.240.0.12:2379 \\
 +
  --event-ttl=1h \\
 +
  --encryption-provider-config=/var/lib/kubernetes/encryption-config.yaml \\
 +
  --kubelet-certificate-authority=/var/lib/kubernetes/ca.pem \\
 +
  --kubelet-client-certificate=/var/lib/kubernetes/kubernetes.pem \\
 +
  --kubelet-client-key=/var/lib/kubernetes/kubernetes-key.pem \\
 +
  --kubelet-https=true \\
 +
  --runtime-config=api/all \\
 +
  --service-account-key-file=/var/lib/kubernetes/service-account.pem \\
 +
  --service-cluster-ip-range=10.32.0.0/24 \\
 +
  --service-node-port-range=30000-32767 \\
 +
  --tls-cert-file=/var/lib/kubernetes/kubernetes.pem \\
 +
  --tls-private-key-file=/var/lib/kubernetes/kubernetes-key.pem \\
 +
  --v=2
 +
Restart=on-failure
 +
RestartSec=5
 +
 +
[Install]
 +
WantedBy=multi-user.target
 +
EOF
 +
</pre>
 +
 +
===Configure the Kubernetes Controller Manager===
 +
 +
* Move the <code>kube-controller-manager</code> kubeconfig into place:
 +
<pre>
 +
sudo mv kube-controller-manager.kubeconfig /var/lib/kubernetes/
 +
</pre>
 +
 +
* Create the <code>kube-controller-manager.service</code> [[systemd]] unit file:
 +
<pre>
 +
cat <<EOF | sudo tee /etc/systemd/system/kube-controller-manager.service
 +
[Unit]
 +
Description=Kubernetes Controller Manager
 +
Documentation=https://github.com/kubernetes/kubernetes
 +
 +
[Service]
 +
ExecStart=/usr/local/bin/kube-controller-manager \\
 +
  --address=0.0.0.0 \\
 +
  --cluster-cidr=10.200.0.0/16 \\
 +
  --cluster-name=kubernetes \\
 +
  --cluster-signing-cert-file=/var/lib/kubernetes/ca.pem \\
 +
  --cluster-signing-key-file=/var/lib/kubernetes/ca-key.pem \\
 +
  --kubeconfig=/var/lib/kubernetes/kube-controller-manager.kubeconfig \\
 +
  --leader-elect=true \\
 +
  --root-ca-file=/var/lib/kubernetes/ca.pem \\
 +
  --service-account-private-key-file=/var/lib/kubernetes/service-account-key.pem \\
 +
  --service-cluster-ip-range=10.32.0.0/24 \\
 +
  --use-service-account-credentials=true \\
 +
  --v=2
 +
Restart=on-failure
 +
RestartSec=5
 +
 +
[Install]
 +
WantedBy=multi-user.target
 +
EOF
 +
</pre>
 +
 +
===Configure the Kubernetes Scheduler===
 +
 +
* Move the <code>kube-scheduler</code> kubeconfig into place:
 +
$ sudo mv kube-scheduler.kubeconfig /var/lib/kubernetes/
 +
 +
* Create the <code>kube-scheduler.yaml</code> configuration file:
 +
<pre>
 +
cat <<EOF | sudo tee /etc/kubernetes/config/kube-scheduler.yaml
 +
apiVersion: kubescheduler.config.k8s.io/v1alpha1
 +
kind: KubeSchedulerConfiguration
 +
clientConnection:
 +
  kubeconfig: "/var/lib/kubernetes/kube-scheduler.kubeconfig"
 +
leaderElection:
 +
  leaderElect: true
 +
EOF
 +
</pre>
 +
 +
* Create the <code>kube-scheduler.service</code> systemd unit file:
 +
<pre>
 +
cat <<EOF | sudo tee /etc/systemd/system/kube-scheduler.service
 +
[Unit]
 +
Description=Kubernetes Scheduler
 +
Documentation=https://github.com/kubernetes/kubernetes
 +
 +
[Service]
 +
ExecStart=/usr/local/bin/kube-scheduler \\
 +
  --config=/etc/kubernetes/config/kube-scheduler.yaml \\
 +
  --v=2
 +
Restart=on-failure
 +
RestartSec=5
 +
 +
[Install]
 +
WantedBy=multi-user.target
 +
EOF
 +
</pre>
 +
 +
===Start the Controller Services===
 +
 +
<pre>
 +
{
 +
  sudo systemctl daemon-reload
 +
  sudo systemctl enable kube-apiserver kube-controller-manager kube-scheduler
 +
  sudo systemctl start kube-apiserver kube-controller-manager kube-scheduler
 +
}
 +
</pre>
 +
Allow up to 10 seconds for the Kubernetes API Server to fully initialize.
 +
 +
===Enable HTTP Health Checks===
 +
 +
A [https://cloud.google.com/compute/docs/load-balancing/network Google Network Load Balancer] will be used to distribute traffic across the three API servers and allow each API server to terminate TLS connections and validate client certificates. The network load balancer only supports HTTP health checks which means the HTTPS endpoint exposed by the API server cannot be used. As a workaround, an [[Nginx]] webserver can be used to proxy HTTP health checks. In this section, Nginx will be installed and configured to accept HTTP health checks on port <code>80</code> and proxy the connections to the API server on <code><nowiki>https://127.0.0.1:6443/healthz</nowiki></code>.
 +
 +
The <code>/healthz</code> API server endpoint does not require authentication by default.
 +
 +
* Install a basic webserver to handle HTTP health checks:
 +
<pre>
 +
$ sudo apt-get install -y nginx
 +
 +
$ cat > kubernetes.default.svc.cluster.local <<EOF
 +
server {
 +
  listen 80;
 +
  server_name kubernetes.default.svc.cluster.local;
 +
 +
  location /healthz {
 +
    proxy_pass https://127.0.0.1:6443/healthz;
 +
    proxy_ssl_trusted_certificate /var/lib/kubernetes/ca.pem;
 +
  }
 +
}
 +
EOF
 +
 +
{
 +
  sudo mv kubernetes.default.svc.cluster.local \
 +
    /etc/nginx/sites-available/kubernetes.default.svc.cluster.local
 +
 +
  sudo ln -s /etc/nginx/sites-available/kubernetes.default.svc.cluster.local \
 +
    /etc/nginx/sites-enabled/
 +
}
 +
 +
$ sudo systemctl restart nginx && sudo systemctl enable nginx
 +
</pre>
 +
 +
===Verification===
 +
 +
<pre>
 +
$ kubectl get componentstatuses --kubeconfig admin.kubeconfig
 +
NAME                STATUS    MESSAGE              ERROR
 +
controller-manager  Healthy  ok
 +
scheduler            Healthy  ok
 +
etcd-2              Healthy  {"health": "true"}
 +
etcd-0              Healthy  {"health": "true"}
 +
etcd-1              Healthy  {"health": "true"}
 +
</pre>
 +
 +
* Test the nginx HTTP health check proxy:
 +
<pre>
 +
$ curl -H "Host: kubernetes.default.svc.cluster.local" -i http://127.0.0.1/healthz
 +
HTTP/1.1 200 OK
 +
Server: nginx/1.14.0 (Ubuntu)
 +
Date: Sun, 30 Sep 2018 17:44:24 GMT
 +
Content-Type: text/plain; charset=utf-8
 +
Content-Length: 2
 +
Connection: keep-alive
 +
 +
ok
 +
</pre>
 +
 +
Note: Remember to run the above commands on each controller node: <code>controller-0</code>, <code>controller-1</code>, and <code>controller-2</code>.
 +
 +
===RBAC for Kubelet Authorization===
 +
 +
In this section, we will configure Role-Based Access Control (RBAC) permissions to allow the Kubernetes API Server to access the Kubelet API on each worker node. Access to the Kubelet API is required for retrieving metrics, logs, and executing commands in pods.
 +
 +
Note: We are also setting the Kubelet <code>--authorization-mode</code> flag to <code>Webhook</code>. Webhook mode uses the [https://kubernetes.io/docs/admin/authorization/#checking-api-access SubjectAccessReview] API to determine authorization.
 +
 +
* SSH into ''just'' the <code>controller-0</code> instance:
 +
$ gcloud compute ssh controller-0
 +
 +
* Create the <code>system:kube-apiserver-to-kubelet</code> [https://kubernetes.io/docs/admin/authorization/rbac/#role-and-clusterrole ClusterRole] with permissions to access the Kubelet API and perform most common tasks associated with managing pods:
 +
<pre>
 +
cat <<EOF | kubectl apply --kubeconfig admin.kubeconfig -f -
 +
apiVersion: rbac.authorization.k8s.io/v1beta1
 +
kind: ClusterRole
 +
metadata:
 +
  annotations:
 +
    rbac.authorization.kubernetes.io/autoupdate: "true"
 +
  labels:
 +
    kubernetes.io/bootstrapping: rbac-defaults
 +
  name: system:kube-apiserver-to-kubelet
 +
rules:
 +
  - apiGroups:
 +
      - ""
 +
    resources:
 +
      - nodes/proxy
 +
      - nodes/stats
 +
      - nodes/log
 +
      - nodes/spec
 +
      - nodes/metrics
 +
    verbs:
 +
      - "*"
 +
EOF
 +
</pre>
 +
 +
The Kubernetes API Server authenticates to the Kubelet as the <code>kubernetes</code> user using the client certificate as defined by the <code>--kubelet-client-certificate</code> flag.
 +
 +
* Bind the <code>system:kube-apiserver-to-kubelet</code> ClusterRole to the <code>kubernetes</code> user:
 +
<pre>
 +
cat <<EOF | kubectl apply --kubeconfig admin.kubeconfig -f -
 +
apiVersion: rbac.authorization.k8s.io/v1beta1
 +
kind: ClusterRoleBinding
 +
metadata:
 +
  name: system:kube-apiserver
 +
  namespace: ""
 +
roleRef:
 +
  apiGroup: rbac.authorization.k8s.io
 +
  kind: ClusterRole
 +
  name: system:kube-apiserver-to-kubelet
 +
subjects:
 +
  - apiGroup: rbac.authorization.k8s.io
 +
    kind: User
 +
    name: kubernetes
 +
EOF
 +
</pre>
 +
 +
==The Kubernetes Frontend Load Balancer==
 +
 +
In this section, we will provision an external load balancer to front the Kubernetes API Servers. The <code>kubernetes-the-hard-way</code> static IP address (created above) will be attached to the resulting load balancer.
 +
 +
Note: The compute instances created in this article will not have permission to complete this section. Run the following commands from the same machine used to create the compute instances.
 +
 +
; Rules for Network Load Balancing
 +
 +
When we create our external load balancer, we need to create an ingress firewall rule for Network Load Balancing, which requires a legacy health check. The source IP ranges for legacy health checks for Network Load Balancing are:
 +
<pre>
 +
35.191.0.0/16
 +
209.85.152.0/22
 +
209.85.204.0/22
 +
</pre>
 +
 +
; Provision a Network Load Balancer
 +
 +
* Create the external load balancer network resources:
 +
<pre>
 +
{
 +
  KUBERNETES_PUBLIC_ADDRESS=$(gcloud compute addresses describe kubernetes-the-hard-way \
 +
    --region $(gcloud config get-value compute/region) \
 +
    --format 'value(address)')
 +
 +
  gcloud compute http-health-checks create kubernetes \
 +
    --description "Kubernetes Health Check" \
 +
    --host "kubernetes.default.svc.cluster.local" \
 +
    --request-path "/healthz"
 +
 +
  gcloud compute firewall-rules create kubernetes-the-hard-way-allow-health-check \
 +
    --network kubernetes-the-hard-way \
 +
    --source-ranges 209.85.152.0/22,209.85.204.0/22,35.191.0.0/16 \
 +
    --allow tcp
 +
 +
  gcloud compute target-pools create kubernetes-target-pool \
 +
    --http-health-check kubernetes
 +
 +
  gcloud compute target-pools add-instances kubernetes-target-pool \
 +
  --instances controller-0,controller-1,controller-2
 +
 +
  gcloud compute forwarding-rules create kubernetes-forwarding-rule \
 +
    --address ${KUBERNETES_PUBLIC_ADDRESS} \
 +
    --ports 6443 \
 +
    --region $(gcloud config get-value compute/region) \
 +
    --target-pool kubernetes-target-pool
 +
}
 +
</pre>
 +
 +
* Get some basic information on our external load balancer:
 +
<pre>
 +
$ gcloud compute target-pools list --filter="name:kubernetes-target-pool"
 +
NAME                    REGION    SESSION_AFFINITY  BACKUP  HEALTH_CHECKS
 +
kubernetes-target-pool  us-west1  NONE                      kubernetes
 +
</pre>
 +
 +
Note: In the GCP API, there is no direct "load balancer" entity; just a collection of components that constitute the load balancer.
 +
 +
===Verification===
 +
 +
* Retrieve the <code>kubernetes-the-hard-way</code> static IP address:
 +
<pre>
 +
KUBERNETES_PUBLIC_ADDRESS=$(gcloud compute addresses describe kubernetes-the-hard-way \
 +
  --region $(gcloud config get-value compute/region) \
 +
  --format 'value(address)')
 +
</pre>
 +
 +
* Make an HTTP request for the Kubernetes version info:
 +
<pre>
 +
$ curl --cacert ca.pem https://${KUBERNETES_PUBLIC_ADDRESS}:6443/version
 +
 +
{
 +
  "major": "1",
 +
  "minor": "15",
 +
  "gitVersion": "v1.15.2",
 +
  "gitCommit": "f6278300bebbb750328ac16ee6dd3aa7d3549568",
 +
  "gitTreeState": "clean",
 +
  "buildDate": "2019-08-05T09:15:22Z",
 +
  "goVersion": "go1.12.5",
 +
  "compiler": "gc",
 +
  "platform": "linux/amd64"
 +
}
 +
</pre>
 +
 +
==Bootstrapping the Kubernetes Worker Nodes==
 +
 +
In this section, we will bootstrap three Kubernetes worker nodes. The following components will be installed on each node:
 +
* [https://github.com/opencontainers/runc runc]
 +
* [https://github.com/google/gvisor gVisor]
 +
* [https://github.com/containernetworking/cni container networking plugins] (CNIs)
 +
* [https://github.com/containerd/containerd containerd]
 +
* [https://kubernetes.io/docs/admin/kubelet kubelet]
 +
* [https://kubernetes.io/docs/concepts/cluster-administration/proxies kube-proxy]
 +
 +
; Prerequisites
 +
 +
The commands in this section must be run on each worker instance/node: <code>worker-0</code>, <code>worker-1</code>, and <code>worker-2</code>.
 +
 +
Using [[tmux]], split your shell into 3 x panes (<code>ctrl + b "</code>) and then log into each worker instance:
 +
<pre>
 +
$ gcloud compute ssh worker-0
 +
ctrl + b o
 +
$ gcloud compute ssh worker-1
 +
ctrl + b o
 +
$ gcloud compute ssh worker-2
 +
</pre>
 +
 +
Now, set tmux to run all subsequent commands (unless otherwise stated) in parallel on all 3 x controller instances (in all 3 x tmux panes):
 +
<pre>
 +
ctrl + b :
 +
set synchronize-panes on # off
 +
#~OR~
 +
setw synchronize-panes # toggles on/off
 +
</pre>
 +
 +
===Provisioning a Kubernetes Worker Node===
 +
 +
* Install the OS dependencies:
 +
<pre>
 +
{
 +
  sudo apt-get update
 +
  sudo apt-get -y install socat conntrack ipset
 +
}
 +
</pre>
 +
 +
Note: The <code>socat</code> binary enables support for the <code>kubectl port-forward</code> command.
 +
 +
; Download and Install Worker Binaries
 +
 +
* Create the installation directories:
 +
<pre>
 +
$ sudo mkdir -p \
 +
    /etc/cni/net.d \
 +
    /opt/cni/bin \
 +
    /var/lib/kubelet \
 +
    /var/lib/kube-proxy \
 +
    /var/lib/kubernetes \
 +
    /var/run/kubernetes
 +
</pre>
 +
 +
<pre>
 +
$ K8S_VERSION=v1.15.2
 +
$ mkdir tar && cd $_
 +
$ wget -q --show-progress --https-only --timestamping \
 +
    "https://github.com/kubernetes-sigs/cri-tools/releases/download/v1.15.0/crictl-v1.15.0-linux-amd64.tar.gz" \
 +
    "https://storage.googleapis.com/kubernetes-the-hard-way/runsc-50c283b9f56bb7200938d9e207355f05f79f0d17" \
 +
    "https://github.com/opencontainers/runc/releases/download/v1.0.0-rc8/runc.amd64" \
 +
    "https://github.com/containernetworking/plugins/releases/download/v0.8.1/cni-plugins-linux-amd64-v0.8.1.tgz" \
 +
    "https://github.com/containerd/containerd/releases/download/v1.2.7/containerd-1.2.7.linux-amd64.tar.gz" \
 +
    "https://storage.googleapis.com/kubernetes-release/release/${K8S_VERSION}/bin/linux/amd64/kubectl" \
 +
    "https://storage.googleapis.com/kubernetes-release/release/${K8S_VERSION}/bin/linux/amd64/kube-proxy" \
 +
    "https://storage.googleapis.com/kubernetes-release/release/${K8S_VERSION}/bin/linux/amd64/kubelet"
 +
</pre>
 +
 +
* Install the worker binaries:
 +
<pre>
 +
cni-plugins-linux-amd64-v0.8.1.tgz
 +
containerd-1.2.7.linux-amd64.tar.gz
 +
crictl-v1.15.0-linux-amd64.tar.gz
 +
kube-proxy
 +
kubectl
 +
kubelet
 +
runc.amd64
 +
runsc-50c283b9f56bb7200938d9e207355f05f79f0d17
 +
{
 +
  sudo mv runsc-50c283b9f56bb7200938d9e207355f05f79f0d17 runsc
 +
  sudo mv runc.amd64 runc
 +
  chmod +x kubectl kube-proxy kubelet runc runsc
 +
  sudo mv kubectl kube-proxy kubelet runc runsc /usr/local/bin/
 +
  sudo tar -xvf crictl-v1.15.0-linux-amd64.tar.gz -C /usr/local/bin/
 +
  sudo tar -xvf cni-plugins-linux-amd64-v0.8.1.tgz -C /opt/cni/bin/
 +
  sudo tar -xvf containerd-1.2.7.linux-amd64.tar.gz -C /
 +
  cd $HOME
 +
}
 +
</pre>
 +
 +
===Configure CNI Networking===
 +
 +
* Retrieve the Pod CIDR range for the current compute instance:
 +
<pre>
 +
POD_CIDR=$(curl -s -H "Metadata-Flavor: Google" \
 +
  http://metadata.google.internal/computeMetadata/v1/instance/attributes/pod-cidr)
 +
</pre>
 +
 +
* Create the <code>bridge</code> network configuration file:
 +
<pre>
 +
cat <<EOF | sudo tee /etc/cni/net.d/10-bridge.conf
 +
{
 +
    "cniVersion": "0.3.1",
 +
    "name": "bridge",
 +
    "type": "bridge",
 +
    "bridge": "cnio0",
 +
    "isGateway": true,
 +
    "ipMasq": true,
 +
    "ipam": {
 +
        "type": "host-local",
 +
        "ranges": [
 +
          [{"subnet": "${POD_CIDR}"}]
 +
        ],
 +
        "routes": [{"dst": "0.0.0.0/0"}]
 +
    }
 +
}
 +
EOF
 +
</pre>
 +
 +
* Create the <code>loopback</code> network configuration file:
 +
<pre>
 +
cat <<EOF | sudo tee /etc/cni/net.d/99-loopback.conf
 +
{
 +
    "cniVersion": "0.3.1",
 +
    "type": "loopback"
 +
}
 +
EOF
 +
</pre>
 +
 +
===Configure containerd===
 +
 +
* Create the containerd configuration file:
 +
sudo mkdir -p /etc/containerd/
 +
<pre>
 +
cat << EOF | sudo tee /etc/containerd/config.toml
 +
[plugins]
 +
  [plugins.cri.containerd]
 +
    snapshotter = "overlayfs"
 +
    [plugins.cri.containerd.default_runtime]
 +
      runtime_type = "io.containerd.runtime.v1.linux"
 +
      runtime_engine = "/usr/local/bin/runc"
 +
      runtime_root = ""
 +
    [plugins.cri.containerd.untrusted_workload_runtime]
 +
      runtime_type = "io.containerd.runtime.v1.linux"
 +
      runtime_engine = "/usr/local/bin/runsc"
 +
      runtime_root = "/run/containerd/runsc"
 +
    [plugins.cri.containerd.gvisor]
 +
      runtime_type = "io.containerd.runtime.v1.linux"
 +
      runtime_engine = "/usr/local/bin/runsc"
 +
      runtime_root = "/run/containerd/runsc"
 +
EOF
 +
</pre>
 +
Note: Untrusted workloads will be run using the gVisor (runsc) runtime.
 +
 +
* Create the <code>containerd.service</code> [[systemd]] unit file:
 +
<pre>
 +
cat << EOF | sudo tee /etc/systemd/system/containerd.service
 +
[Unit]
 +
Description=containerd container runtime
 +
Documentation=https://containerd.io
 +
After=network.target
 +
 +
[Service]
 +
ExecStartPre=/sbin/modprobe overlay
 +
ExecStart=/bin/containerd
 +
Restart=always
 +
RestartSec=5
 +
Delegate=yes
 +
KillMode=process
 +
OOMScoreAdjust=-999
 +
LimitNOFILE=1048576
 +
LimitNPROC=infinity
 +
LimitCORE=infinity
 +
 +
[Install]
 +
WantedBy=multi-user.target
 +
EOF
 +
</pre>
 +
 +
===Configure the Kubelet===
 +
 +
<pre>
 +
{
 +
  sudo mv ${HOSTNAME}-key.pem ${HOSTNAME}.pem /var/lib/kubelet/
 +
  sudo mv ${HOSTNAME}.kubeconfig /var/lib/kubelet/kubeconfig
 +
  sudo mv ca.pem /var/lib/kubernetes/
 +
}
 +
</pre>
 +
 +
* Create the <code>kubelet-config.yaml</code> configuration file:
 +
<pre>
 +
cat << EOF | sudo tee /var/lib/kubelet/kubelet-config.yaml
 +
kind: KubeletConfiguration
 +
apiVersion: kubelet.config.k8s.io/v1beta1
 +
authentication:
 +
  anonymous:
 +
    enabled: false
 +
  webhook:
 +
    enabled: true
 +
  x509:
 +
    clientCAFile: "/var/lib/kubernetes/ca.pem"
 +
authorization:
 +
  mode: Webhook
 +
clusterDomain: "cluster.local"
 +
clusterDNS:
 +
  - "10.32.0.10"
 +
podCIDR: "${POD_CIDR}"
 +
resolvConf: "/run/systemd/resolve/resolv.conf"
 +
runtimeRequestTimeout: "15m"
 +
tlsCertFile: "/var/lib/kubelet/${HOSTNAME}.pem"
 +
tlsPrivateKeyFile: "/var/lib/kubelet/${HOSTNAME}-key.pem"
 +
EOF
 +
</pre>
 +
 +
Note: The <code>resolvConf</code> configuration is used to avoid loops when using CoreDNS for service discovery on systems running <code>systemd-resolved</code>.
 +
 +
* Create the <code>kubelet.service</code> systemd unit file:
 +
<pre>
 +
cat << EOF | sudo tee /etc/systemd/system/kubelet.service
 +
[Unit]
 +
Description=Kubernetes Kubelet
 +
Documentation=https://github.com/kubernetes/kubernetes
 +
After=containerd.service
 +
Requires=containerd.service
 +
 +
[Service]
 +
ExecStart=/usr/local/bin/kubelet \\
 +
  --config=/var/lib/kubelet/kubelet-config.yaml \\
 +
  --container-runtime=remote \\
 +
  --container-runtime-endpoint=unix:///var/run/containerd/containerd.sock \\
 +
  --image-pull-progress-deadline=2m \\
 +
  --kubeconfig=/var/lib/kubelet/kubeconfig \\
 +
  --network-plugin=cni \\
 +
  --register-node=true \\
 +
  --v=2
 +
Restart=on-failure
 +
RestartSec=5
 +
 +
[Install]
 +
WantedBy=multi-user.target
 +
EOF
 +
</pre>
 +
 +
===Configure the Kubernetes Proxy===
 +
 +
$ sudo mv kube-proxy.kubeconfig /var/lib/kube-proxy/kubeconfig
 +
 +
* Create the <code>kube-proxy-config.yaml</code> configuration file:
 +
<pre>
 +
cat << EOF | sudo tee /var/lib/kube-proxy/kube-proxy-config.yaml
 +
kind: KubeProxyConfiguration
 +
apiVersion: kubeproxy.config.k8s.io/v1alpha1
 +
clientConnection:
 +
  kubeconfig: "/var/lib/kube-proxy/kubeconfig"
 +
mode: "iptables"
 +
clusterCIDR: "10.200.0.0/16"
 +
EOF
 +
</pre>
 +
 +
* Create the <code>kube-proxy.service</code> systemd unit file:
 +
<pre>
 +
cat << EOF | sudo tee /etc/systemd/system/kube-proxy.service
 +
[Unit]
 +
Description=Kubernetes Kube Proxy
 +
Documentation=https://github.com/kubernetes/kubernetes
 +
 +
[Service]
 +
ExecStart=/usr/local/bin/kube-proxy \\
 +
  --config=/var/lib/kube-proxy/kube-proxy-config.yaml
 +
Restart=on-failure
 +
RestartSec=5
 +
 +
[Install]
 +
WantedBy=multi-user.target
 +
EOF
 +
</pre>
 +
 +
===Start the Worker Services===
 +
 +
<pre>
 +
{
 +
  sudo systemctl daemon-reload
 +
  sudo systemctl enable containerd kubelet kube-proxy
 +
  sudo systemctl start containerd kubelet kube-proxy
 +
}
 +
</pre>
 +
Note: Remember to run the above commands on each worker node: <code>worker-0</code>, <code>worker-1</code>, and <code>worker-2</code>.
 +
 +
* Check the statuses of the worker services:
 +
$ systemctl status containerd kubelet kube-proxy
 +
 +
===Verification===
 +
 +
NOTE: The compute instances created in this article will not have permission to complete this section. Run the following commands from the same machine used to create the compute instances.
 +
 +
* List the registered Kubernetes nodes:
 +
<pre>
 +
gcloud compute ssh controller-0 \
 +
  --command "kubectl --kubeconfig admin.kubeconfig get nodes -o wide"
 +
 +
NAME      STATUS  ROLES    AGE    VERSION  INTERNAL-IP  EXTERNAL-IP  OS-IMAGE            KERNEL-VERSION    CONTAINER-RUNTIME
 +
worker-0  Ready    <none>  3m3s  v1.15.2  10.240.0.20  <none>        Ubuntu 18.04.2 LTS  4.15.0-1037-gcp  containerd://1.2.7
 +
worker-1  Ready    <none>  3m3s  v1.15.2  10.240.0.21  <none>        Ubuntu 18.04.2 LTS  4.15.0-1037-gcp  containerd://1.2.7
 +
worker-2  Ready    <none>  3m3s  v1.15.2  10.240.0.22  <none>        Ubuntu 18.04.2 LTS  4.15.0-1037-gcp  containerd://1.2.7
 +
</pre>
 +
 +
==Configuring kubectl for Remote Access==
 +
 +
In this section, we will generate a kubeconfig file for the <code>kubectl</code> command line utility based on the <code>admin</code> user credentials.
 +
 +
NOTE: Run the commands in this section from the same directory used to generate the admin client certificates.
 +
 +
; The Admin Kubernetes Configuration File
 +
 +
Each kubeconfig requires a Kubernetes API Server to connect to. To support high availability the IP address assigned to the external load balancer fronting the Kubernetes API Servers will be used.
 +
 +
'''WARNING:''' The following commands will overwrite your current/default kubeconfig (whatever <code>KUBECONFIG</code> environment variable is pointing to, if it is set. If it is not set, then it will overwrite your <code>$HOME/.kube/config</code> file).
 +
 +
* Generate a kubeconfig file suitable for authenticating as the <code>admin</code> user:
 +
<pre>
 +
{
 +
  KUBERNETES_PUBLIC_ADDRESS=$(gcloud compute addresses describe kubernetes-the-hard-way \
 +
    --region $(gcloud config get-value compute/region) \
 +
    --format 'value(address)')
 +
 +
  kubectl config set-cluster kubernetes-the-hard-way \
 +
    --certificate-authority=ca.pem \
 +
    --embed-certs=true \
 +
    --server=https://${KUBERNETES_PUBLIC_ADDRESS}:6443
 +
 +
  kubectl config set-credentials admin \
 +
    --client-certificate=admin.pem \
 +
    --client-key=admin-key.pem
 +
 +
  kubectl config set-context kubernetes-the-hard-way \
 +
    --cluster=kubernetes-the-hard-way \
 +
    --user=admin
 +
 +
  kubectl config use-context kubernetes-the-hard-way
 +
}
 +
</pre>
 +
 +
; Verification
 +
 +
* Check the health of the remote Kubernetes cluster:
 +
<pre>
 +
$ kubectl get componentstatuses
 +
 +
NAME                STATUS    MESSAGE            ERROR
 +
scheduler            Healthy  ok                 
 +
controller-manager  Healthy  ok                 
 +
etcd-1              Healthy  {"health":"true"} 
 +
etcd-2              Healthy  {"health":"true"} 
 +
etcd-0              Healthy  {"health":"true"}
 +
</pre>
 +
 +
==Provisioning Pod Network Routes==
 +
 +
Pods scheduled to a node receive an IP address from the node's Pod CIDR range. At this point, pods can not communicate with other pods running on different nodes due to missing network [https://cloud.google.com/compute/docs/vpc/routes routes].
 +
 +
In this section, we will create a route for each worker node that maps the node's Pod CIDR range to the node's internal IP address.
 +
 +
Note: There are [https://kubernetes.io/docs/concepts/cluster-administration/networking/#how-to-achieve-this other ways] to implement the Kubernetes networking model.
 +
 +
===The Routing Table===
 +
 +
In this section, we will gather the information required to create routes in the <code>kubernetes-the-hard-way</code> VPC network.
 +
 +
* Print the internal IP address and Pod CIDR range for each worker instance:
 +
<pre>
 +
for instance in worker-0 worker-1 worker-2; do
 +
  gcloud compute instances describe ${instance} \
 +
    --format 'value[separator=" "](networkInterfaces[0].networkIP,metadata.items[0].value)'
 +
done
 +
 +
10.240.0.20 10.200.0.0/24
 +
10.240.0.21 10.200.1.0/24
 +
10.240.0.22 10.200.2.0/24
 +
</pre>
 +
 +
===Routes===
 +
 +
* List the default routes in the <code>kubernetes-the-hard-way</code> VPC network:
 +
<pre>
 +
$ gcloud compute routes list --filter "network: kubernetes-the-hard-way"
 +
NAME                            NETWORK                  DEST_RANGE    NEXT_HOP                  PRIORITY
 +
default-route-294de28447c4e405  kubernetes-the-hard-way  0.0.0.0/0      default-internet-gateway  1000
 +
default-route-638561d1ca3f4621  kubernetes-the-hard-way  10.240.0.0/24  kubernetes-the-hard-way  1000
 +
</pre>
 +
 +
* Create network routes for each worker instance:
 +
<pre>
 +
for i in 0 1 2; do
 +
  gcloud compute routes create kubernetes-route-10-200-${i}-0-24 \
 +
    --network kubernetes-the-hard-way \
 +
    --next-hop-address 10.240.0.2${i} \
 +
    --destination-range 10.200.${i}.0/24
 +
done
 +
</pre>
 +
 +
* List the routes in the <code>kubernetes-the-hard-way</code> VPC network:
 +
<pre>
 +
$ gcloud compute routes list --filter "network: kubernetes-the-hard-way"
 +
 +
NAME                            NETWORK                  DEST_RANGE    NEXT_HOP                  PRIORITY
 +
default-route-294de28447c4e405  kubernetes-the-hard-way  0.0.0.0/0      default-internet-gateway  1000
 +
default-route-638561d1ca3f4621  kubernetes-the-hard-way  10.240.0.0/24  kubernetes-the-hard-way  1000
 +
kubernetes-route-10-200-0-0-24  kubernetes-the-hard-way  10.200.0.0/24  10.240.0.20              1000
 +
kubernetes-route-10-200-1-0-24  kubernetes-the-hard-way  10.200.1.0/24  10.240.0.21              1000
 +
kubernetes-route-10-200-2-0-24  kubernetes-the-hard-way  10.200.2.0/24  10.240.0.22              1000
 +
</pre>
 +
 +
==Deploying the DNS Cluster Add-on==
 +
 +
In this section, we will deploy the [https://kubernetes.io/docs/concepts/services-networking/dns-pod-service/ DNS add-on] which provides DNS based service discovery, backed by [https://coredns.io/ CoreDNS], to applications running inside the Kubernetes cluster.
 +
 +
===The DNS Cluster Add-on===
 +
 +
* Deploy the <code>coredns</code> cluster add-on:
 +
<pre>
 +
$ kubectl apply -f https://storage.googleapis.com/kubernetes-the-hard-way/coredns.yaml
 +
 +
serviceaccount/coredns created
 +
clusterrole.rbac.authorization.k8s.io/system:coredns created
 +
clusterrolebinding.rbac.authorization.k8s.io/system:coredns created
 +
configmap/coredns created
 +
deployment.extensions/coredns created
 +
service/kube-dns created
 +
</pre>
 +
 +
* List the pods created by the <code>kube-dns</code> deployment:
 +
<pre>
 +
$ kubectl -n kube-system get pods -l k8s-app=kube-dns
 +
 +
NAME                      READY  STATUS    RESTARTS  AGE
 +
coredns-7945fb857d-kpd67  1/1    Running  0          40s
 +
coredns-7945fb857d-rpvwl  1/1    Running  0          40s
 +
</pre>
 +
 +
===Verification===
 +
 +
* Create a busybox deployment:
 +
<pre>
 +
$ kubectl run busybox --image=busybox:1.31.0 --command -- sleep 3600
 +
</pre>
 +
 +
* List the pod created by the <code>busybox</code> deployment:
 +
<pre>
 +
$ kubectl get pods -l run=busybox
 +
NAME                      READY  STATUS    RESTARTS  AGE
 +
busybox-57786959c7-xpfxv  1/1    Running  0          16s
 +
</pre>
 +
 +
* Retrieve the full name of the <code>busybox</code> pod:
 +
<pre>
 +
$ POD_NAME=$(kubectl get pods -l run=busybox -o jsonpath="{.items[0].metadata.name}")
 +
$ echo $POD_NAME
 +
busybox-57786959c7-xpfxv
 +
</pre>
 +
 +
* Execute a DNS lookup for the <code>kubernetes</code> service inside the <code>busybox</code> pod:
 +
<pre>
 +
$ kubectl exec -ti $POD_NAME -- nslookup kubernetes
 +
 +
Server:    10.32.0.10
 +
Address 1: 10.32.0.10 kube-dns.kube-system.svc.cluster.local
 +
 +
Name:      kubernetes
 +
Address 1: 10.32.0.1 kubernetes.default.svc.cluster.local
 +
</pre>
 +
 +
==Smoke testing==
 +
 +
In this section, we will complete a series of tasks to ensure your Kubernetes cluster is functioning correctly and passes a build verification test (BVT).
 +
 +
===Data Encryption===
 +
 +
Goal: Verify the ability to [https://kubernetes.io/docs/tasks/administer-cluster/encrypt-data/#verifying-that-data-is-encrypted encrypt secret data at rest].
 +
 +
* Create a generic secret:
 +
<pre>
 +
$ kubectl create secret generic kubernetes-the-hard-way \
 +
    --from-literal="mykey=mydata"
 +
</pre>
 +
 +
* Print a hexdump of the <code>kubernetes-the-hard-way</code> secret stored in etcd:
 +
<pre>
 +
$ gcloud compute ssh controller-0 \
 +
  --command "sudo ETCDCTL_API=3 etcdctl get \
 +
  --endpoints=https://127.0.0.1:2379 \
 +
  --cacert=/etc/etcd/ca.pem \
 +
  --cert=/etc/etcd/kubernetes.pem \
 +
  --key=/etc/etcd/kubernetes-key.pem\
 +
  /registry/secrets/default/kubernetes-the-hard-way | hexdump -C"
 +
 +
00000000  2f 72 65 67 69 73 74 72  79 2f 73 65 63 72 65 74  |/registry/secret|
 +
00000010  73 2f 64 65 66 61 75 6c  74 2f 6b 75 62 65 72 6e  |s/default/kubern|
 +
00000020  65 74 65 73 2d 74 68 65  2d 68 61 72 64 2d 77 61  |etes-the-hard-wa|
 +
00000030  79 0a 6b 38 73 3a 65 6e  63 3a 61 65 73 63 62 63  |y.k8s:enc:aescbc|
 +
00000040  3a 76 31 3a 6b 65 79 31  3a a5 d7 cd 20 d1 12 a3  |:v1:key1:... ...|
 +
00000050  47 13 fe cb ea b1 9f f2  1f 63 7d 1f c4 03 cb 3f  |G........c}....?|
 +
00000060  27 b4 3e 40 9a 32 0b 91  a5 84 bf ee 1c b5 9e ea  |'.>@.2..........|
 +
00000070  4c a3 fb e1 6d 83 18 1e  50 42 0b 2d cb 90 c8 92  |L...m...PB.-....|
 +
00000080  f5 29 81 2a 01 db 9d 22  1f 67 3b f4 fd a8 76 59  |.).*...".g;...vY|
 +
00000090  e8 1e e0 a5 91 65 c3 5d  17 0a 32 fc 5e 73 4d 35  |.....e.]..2.^sM5|
 +
000000a0  69 a1 78 d9 a9 83 6b 53  c3 5e aa c9 e0 c4 72 6a  |i.x...kS.^....rj|
 +
000000b0  26 56 8b 5e fc 34 6b f0  12 1f 5b 0a 70 aa 07 de  |&V.^.4k...[.p...|
 +
000000c0  0a de 76 4b ed be 09 61  2c 43 5e e3 35 0b 43 60  |..vK...a,C^.5.C`|
 +
000000d0  e3 d5 34 0b 9e 7b 05 67  30 3c 49 a8 33 9c f2 da  |..4..{.g0<I.3...|
 +
000000e0  4f c9 e9 b5 54 31 f8 14  75 0a                    |O...T1..u.|
 +
000000ea
 +
 +
#~OR~
 +
 +
$ gcloud compute ssh controller-0 \
 +
  --command "sudo ETCDCTL_API=3 etcdctl get \
 +
  --endpoints=https://127.0.0.1:2379 \
 +
  --cacert=/etc/etcd/ca.pem \
 +
  --cert=/etc/etcd/kubernetes.pem \
 +
  --key=/etc/etcd/kubernetes-key.pem\
 +
  /registry/secrets/default/kubernetes-the-hard-way -w fields | grep Value"
 +
 +
"Value" : "k8s:enc:aescbc:v1:key1:\xa5..."
 +
</pre>
 +
 +
The etcd key should be prefixed with <code>k8s:enc:aescbc:v1:key1</code>, which indicates the Advanced Encryption Standard (AES) - CBC (Cipher Blocker Chaining) provider was used to encrypt the data with the <code>key1</code> encryption key. See: [[:wikipedia:Block cipher mode of operation]] for details.
 +
 +
===Deployments===
 +
 +
In this section, we will verify the ability to create and manage Deployments.
 +
 +
* Create a deployment for an Nginx web server:
 +
<pre>
 +
$ kubectl run nginx --image=nginx
 +
</pre>
 +
 +
* List the pod created by the nginx deployment:
 +
<pre>
 +
$ kubectl get pods -l run=nginx
 +
 +
NAME                    READY  STATUS    RESTARTS  AGE
 +
nginx-7bb7cd8db5-7nrsw  1/1    Running  0          14s
 +
</pre>
 +
 +
===Port Forwarding===
 +
 +
In this section, we will verify the ability to access applications remotely using [https://kubernetes.io/docs/tasks/access-application-cluster/port-forward-access-application-cluster/ port forwarding].
 +
 +
* Retrieve the full name of the nginx pod:
 +
<pre>
 +
POD_NAME=$(kubectl get pods -l run=nginx -o jsonpath="{.items[0].metadata.name}")
 +
</pre>
 +
 +
* Forward port 8080 on your local machine to port 80 of the nginx pod:
 +
<pre>
 +
$ kubectl port-forward $POD_NAME 8080:80
 +
 +
Forwarding from 127.0.0.1:8080 -> 80
 +
Forwarding from [::1]:8080 -> 80
 +
</pre>
 +
 +
* In a new terminal make an HTTP request using the forwarding address:
 +
<pre>
 +
$ curl --head http://127.0.0.1:8080
 +
HTTP/1.1 200 OK
 +
Server: nginx/1.17.2
 +
Date: Fri, 09 Aug 2019 22:44:03 GMT
 +
Content-Type: text/html
 +
Content-Length: 612
 +
Last-Modified: Tue, 23 Jul 2019 11:45:37 GMT
 +
Connection: keep-alive
 +
ETag: "5d36f361-264"
 +
Accept-Ranges: bytes
 +
</pre>
 +
 +
* Switch back to the previous terminal and stop the port forwarding to the nginx pod:
 +
<pre>
 +
Forwarding from 127.0.0.1:8080 -> 80
 +
Forwarding from [::1]:8080 -> 80
 +
Handling connection for 8080
 +
^C
 +
</pre>
 +
 +
===Logs===
 +
 +
In this section, we will verify the ability to [https://kubernetes.io/docs/concepts/cluster-administration/logging/ retrieve container logs].
 +
 +
* Print the nginx pod logs:
 +
<pre>
 +
$ kubectl logs $POD_NAME
 +
127.0.0.1 - - [09/Aug/2019:22:44:03 +0000] "HEAD / HTTP/1.1" 200 0 "-" "curl/7.58.0" "-"
 +
</pre>
 +
 +
===Exec===
 +
 +
In this section, we will verify the ability to [https://kubernetes.io/docs/tasks/debug-application-cluster/get-shell-running-container/#running-individual-commands-in-a-container execute commands in a container].
 +
 +
* Print the nginx version by executing the nginx -v command in the nginx container:
 +
<pre>
 +
$ kubectl exec -ti $POD_NAME -- nginx -v
 +
nginx version: nginx/1.17.2
 +
</pre>
 +
 +
===Services===
 +
 +
In this section, we will verify the ability to expose applications using a [https://kubernetes.io/docs/concepts/services-networking/service/ Service].
 +
 +
* Expose the nginx deployment using a [https://kubernetes.io/docs/concepts/services-networking/service/#type-nodeport NodePort] service:
 +
<pre>
 +
$ kubectl expose deployment nginx --port 80 --type NodePort
 +
 +
$ kubectl get svc -l run=nginx
 +
NAME    TYPE      CLUSTER-IP    EXTERNAL-IP  PORT(S)        AGE
 +
nginx  NodePort  10.32.0.112  <none>        80:31119/TCP  23s
 +
</pre>
 +
 +
NOTE: The LoadBalancer service type can not be used because your cluster is not configured with [https://kubernetes.io/docs/getting-started-guides/scratch/#cloud-provider cloud provider integration]. Setting up cloud provider integration is out of scope for this article.
 +
 +
* Retrieve the node port assigned to the nginx service:
 +
<pre>
 +
NODE_PORT=$(kubectl get svc nginx \
 +
  --output=jsonpath='{range .spec.ports[0]}{.nodePort}')
 +
 +
$ echo $NODE_PORT
 +
31119
 +
</pre>
 +
 +
* Create a firewall rule that allows remote access to the nginx node port:
 +
<pre>
 +
$ gcloud compute firewall-rules create kubernetes-the-hard-way-allow-nginx-service \
 +
  --allow=tcp:${NODE_PORT} \
 +
  --network kubernetes-the-hard-way
 +
 +
$ gcloud compute firewall-rules list --filter="name ~ allow-nginx"
 +
NAME                                        NETWORK                  DIRECTION  PRIORITY  ALLOW      DENY  DISABLED
 +
kubernetes-the-hard-way-allow-nginx-service  kubernetes-the-hard-way  INGRESS    1000      tcp:31119        False
 +
</pre>
 +
 +
* Retrieve the external IP address of a worker instance:
 +
<pre>
 +
EXTERNAL_IP=$(gcloud compute instances describe worker-0 \
 +
  --format 'value(networkInterfaces[0].accessConfigs[0].natIP)')
 +
</pre>
 +
 +
* Make an HTTP request using the external IP address and the nginx node port:
 +
<pre>
 +
$ curl -I http://${EXTERNAL_IP}:${NODE_PORT}
 +
HTTP/1.1 200 OK
 +
Server: nginx/1.17.2
 +
Date: Fri, 09 Aug 2019 23:15:01 GMT
 +
Content-Type: text/html
 +
Content-Length: 612
 +
Last-Modified: Tue, 23 Jul 2019 11:45:37 GMT
 +
Connection: keep-alive
 +
ETag: "5d36f361-264"
 +
Accept-Ranges: bytes
 +
</pre>
 +
 +
===Untrusted Workloads===
 +
 +
This section will verify the ability to run untrusted workloads using [https://github.com/google/gvisor gVisor].
 +
 +
* Create the untrusted pod:
 +
<pre>
 +
cat << EOF | kubectl apply -f -
 +
apiVersion: v1
 +
kind: Pod
 +
metadata:
 +
  name: untrusted
 +
  annotations:
 +
    io.kubernetes.cri.untrusted-workload: "true"
 +
spec:
 +
  containers:
 +
    - name: webserver
 +
      image: gcr.io/hightowerlabs/helloworld:2.0.0
 +
EOF
 +
</pre>
 +
 +
; Verification
 +
 +
* Verify the untrusted pod is running under gVisor (runsc) by inspecting the assigned worker node:
 +
<pre>
 +
$ kubectl get pods -o wide
 +
 +
NAME                      READY  STATUS    RESTARTS  AGE  IP          NODE      NOMINATED NODE  READINESS GATES
 +
busybox-57786959c7-5wlf4  1/1    Running  1          61m  10.200.1.4  worker-1  <none>          <none>
 +
nginx-7bb7cd8db5-7nrsw    1/1    Running  0          35m  10.200.0.3  worker-0  <none>          <none>
 +
untrusted                  1/1    Running  0          67s  10.200.1.5  worker-1  <none>          <none>
 +
</pre>
 +
 +
* Get the node name where the untrusted pod is running:
 +
<pre>
 +
$ INSTANCE_NAME=$(kubectl get pod untrusted --output=jsonpath='{.spec.nodeName}')
 +
 +
$ echo $INSTANCE_NAME
 +
worker-1
 +
</pre>
 +
 +
* SSH into the worker node:
 +
<pre>
 +
$ gcloud compute ssh ${INSTANCE_NAME}
 +
</pre>
 +
 +
* List the containers running under gVisor:
 +
<pre>
 +
$ sudo runsc --root /run/containerd/runsc/k8s.io list
 +
 +
I0809 23:19:45.762228  18463 x:0] ***************************
 +
I0809 23:19:45.762415  18463 x:0] Args: [runsc --root /run/containerd/runsc/k8s.io list]
 +
I0809 23:19:45.762481  18463 x:0] Git Revision: 50c283b9f56bb7200938d9e207355f05f79f0d17
 +
I0809 23:19:45.762535  18463 x:0] PID: 18463
 +
I0809 23:19:45.762602  18463 x:0] UID: 0, GID: 0
 +
I0809 23:19:45.762652  18463 x:0] Configuration:
 +
I0809 23:19:45.762695  18463 x:0] RootDir: /run/containerd/runsc/k8s.io
 +
I0809 23:19:45.762791  18463 x:0] Platform: ptrace
 +
I0809 23:19:45.762899  18463 x:0] FileAccess: exclusive, overlay: false
 +
I0809 23:19:45.762996  18463 x:0] Network: sandbox, logging: false
 +
I0809 23:19:45.763093  18463 x:0] Strace: false, max size: 1024, syscalls: []
 +
I0809 23:19:45.763188  18463 x:0] ***************************
 +
ID                                                                PID        STATUS      BUNDLE                                                                                                                  CREATED                OWNER
 +
db3d2549c91111eb68467e9aba28723743e34965f0cf6a9683206b2c93bba1bd  17834      running    /run/containerd/io.containerd.runtime.v1.linux/k8s.io/db3d2549c91111eb68467e9aba28723743e34965f0cf6a9683206b2c93bba1bd  0001-01-01T00:00:00Z 
 +
f8dcc505e3e0850da6e33d5fd9e35308951afe8a5ab840a31e19ef93f16dbe7f  17901      running    /run/containerd/io.containerd.runtime.v1.linux/k8s.io/f8dcc505e3e0850da6e33d5fd9e35308951afe8a5ab840a31e19ef93f16dbe7f  0001-01-01T00:00:00Z 
 +
I0809 23:19:45.766604  18463 x:0] Exiting with status: 0
 +
</pre>
 +
 +
* Get the ID of the untrusted pod:
 +
<pre>
 +
$ POD_ID=$(sudo crictl -r unix:///var/run/containerd/containerd.sock \
 +
    pods --name untrusted -q)
 +
 +
$ echo $POD_ID
 +
db3d2549c91111eb68467e9aba28723743e34965f0cf6a9683206b2c93bba1bd
 +
</pre>
 +
 +
* Get the ID of the webserver container running in the untrusted pod:
 +
<pre>
 +
$ CONTAINER_ID=$(sudo crictl -r unix:///var/run/containerd/containerd.sock \
 +
    ps -p ${POD_ID} -q)
 +
 +
$ echo $CONTAINER_ID
 +
f8dcc505e3e0850da6e33d5fd9e35308951afe8a5ab840a31e19ef93f16dbe7f
 +
</pre>
 +
 +
* Use the gVisor runsc command to display the processes running inside the webserver container:
 +
<pre>
 +
$ sudo runsc --root /run/containerd/runsc/k8s.io ps ${CONTAINER_ID}
 +
 +
I0809 23:22:26.200992  18720 x:0] ***************************
 +
I0809 23:22:26.201201  18720 x:0] Args: [runsc --root /run/containerd/runsc/k8s.io ps f8dcc505e3e0850da6e33d5fd9e35308951afe8a5ab840a31e19ef93f16dbe7f]
 +
I0809 23:22:26.201275  18720 x:0] Git Revision: 50c283b9f56bb7200938d9e207355f05f79f0d17
 +
I0809 23:22:26.201331  18720 x:0] PID: 18720
 +
I0809 23:22:26.201388  18720 x:0] UID: 0, GID: 0
 +
I0809 23:22:26.201449  18720 x:0] Configuration:
 +
I0809 23:22:26.201494  18720 x:0] RootDir: /run/containerd/runsc/k8s.io
 +
I0809 23:22:26.201590  18720 x:0] Platform: ptrace
 +
I0809 23:22:26.201792  18720 x:0] FileAccess: exclusive, overlay: false
 +
I0809 23:22:26.201900  18720 x:0] Network: sandbox, logging: false
 +
I0809 23:22:26.201999  18720 x:0] Strace: false, max size: 1024, syscalls: []
 +
I0809 23:22:26.202095  18720 x:0] ***************************
 +
UID      PID      PPID      C        STIME    TIME      CMD
 +
0        1        0        0        23:16    0s        app
 +
I0809 23:22:26.203699  18720 x:0] Exiting with status: 0
 +
</pre>
 +
 +
==Cleanup==
 +
 +
In this section, we will delete everything we created in GCP in this article.
 +
 +
===Compute Instances===
 +
 +
* Delete the controller and worker compute instances:
 +
<pre>
 +
gcloud -q compute instances delete \
 +
  controller-0 controller-1 controller-2 \
 +
  worker-0 worker-1 worker-2
 +
</pre>
 +
 +
===Networking===
 +
 +
* Delete the external load balancer network resources:
 +
<pre>
 +
{
 +
  gcloud -q compute forwarding-rules delete kubernetes-forwarding-rule \
 +
    --region $(gcloud config get-value compute/region)
 +
 +
  gcloud -q compute target-pools delete kubernetes-target-pool
 +
 +
  gcloud -q compute http-health-checks delete kubernetes
 +
 +
  gcloud -q compute addresses delete kubernetes-the-hard-way
 +
}
 +
</pre>
 +
 +
* Delete the kubernetes-the-hard-way firewall rules:
 +
<pre>
 +
gcloud -q compute firewall-rules delete \
 +
  kubernetes-the-hard-way-allow-nginx-service \
 +
  kubernetes-the-hard-way-allow-internal \
 +
  kubernetes-the-hard-way-allow-external \
 +
  kubernetes-the-hard-way-allow-health-check
 +
</pre>
 +
 +
* Delete the kubernetes-the-hard-way network VPC:
 +
<pre>
 +
{
 +
  gcloud -q compute routes delete \
 +
    kubernetes-route-10-200-0-0-24 \
 +
    kubernetes-route-10-200-1-0-24 \
 +
    kubernetes-route-10-200-2-0-24
 +
 +
  gcloud -q compute networks subnets delete kubernetes
 +
 +
  gcloud -q compute networks delete kubernetes-the-hard-way
 +
}
 
</pre>
 
</pre>
  

Latest revision as of 23:27, 9 August 2019

This article will show how to setup Kubernetes The Hard Way, as originally developed by Kelsey Hightower. I will add my own additions, changes, alterations, etc. to the process (and this will be continually expanded upon).

I will show you how to set up Kubernetes from scratch using Google Cloud Platform (GCP) VMs running Ubuntu 18.04.

I will use the latest version of Kubernetes (as of August 2019): 

$ curl -sSL https://dl.k8s.io/release/stable.txt
v1.15.2

Install the client tools

Note: See here for how to install on other OSes.

In this section, we will install the command line utilities required to complete this tutorial:

Install CFSSL

The cfssl and cfssljson command line utilities will be used to provision a PKI Infrastructure and generate TLS certificates. 

$ wget -q --show-progress --https-only --timestamping \
    https://pkg.cfssl.org/R1.2/cfssl_linux-amd64 \
    https://pkg.cfssl.org/R1.2/cfssljson_linux-amd64

$ chmod +x cfssl_linux-amd64 cfssljson_linux-amd64
$ sudo mv cfssl_linux-amd64 /usr/local/bin/cfssl
$ sudo mv cfssljson_linux-amd64 /usr/local/bin/cfssljson
  • Verify cfssl version 1.2.0 or higher is installed:
$ cfssl version
Version: 1.2.0
Revision: dev
Runtime: go1.6

Note: The cfssljson command line utility does not provide a way to print its version.

Install kubectl

The kubectl command line utility is used to interact with the Kubernetes API Server.

  • Download and install kubectl from the official release binaries:
$ K8S_VERSION=$(curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)
$ curl -LO https://storage.googleapis.com/kubernetes-release/release/${K8S_VERSION}/bin/linux/amd64/kubectl
$ chmod +x kubectl
$ sudo mv kubectl /usr/local/bin/
  • Verify kubectl version 1.12.0 or higher is installed:
$ kubectl version --client
Client Version: version.Info{Major:"1", Minor:"15", GitVersion:"v1.15.0", GitCommit:"e8462b5b5dc2584fdcd18e6bcfe9f1e4d970a529", GitTreeState:"clean", BuildDate:"2019-06-19T16:40:16Z", GoVersion:"go1.12.5", Compiler:"gc", Platform:"linux/amd64"}

Provisioning compute resources

Networking

Virtual Private Cloud Network (VPC)

In this section, a dedicated Virtual Private Cloud (VPC) network will be setup to host the Kubernetes cluster.

  • Create the kubernetes-the-hard-way custom VPC network:
$ gcloud compute networks create kubernetes-the-hard-way --subnet-mode custom
Created [https://www.googleapis.com/compute/v1/projects/<project-name>/global/networks/kubernetes-the-hard-way].

$ gcloud compute networks list --filter="name~'.*hard.*'"
NAME                     SUBNET_MODE  BGP_ROUTING_MODE  IPV4_RANGE  GATEWAY_IPV4
kubernetes-the-hard-way  CUSTOM       REGIONAL

A subnet must be provisioned with an IP address range large enough to assign a private IP address to each node in the Kubernetes cluster.

  • Create the kubernetes subnet in the kubernetes-the-hard-way VPC network:
$ gcloud compute networks subnets create kubernetes \
  --network kubernetes-the-hard-way \
  --range 10.240.0.0/24
Created [https://www.googleapis.com/compute/v1/projects/<project-name>/regions/us-west1/subnetworks/kubernetes].

$ gcloud compute networks subnets list --filter="network ~ kubernetes-the-hard-way"
NAME        REGION    NETWORK                  RANGE
kubernetes  us-west1  kubernetes-the-hard-way  10.240.0.0/24

Note: The 10.240.0.0/24 IP address range can host up to 254 compute instances.

Firewall rules
  • Create a firewall rule that allows internal communication across all protocols:
$ gcloud compute firewall-rules create kubernetes-the-hard-way-allow-internal \
  --allow tcp,udp,icmp \
  --network kubernetes-the-hard-way \
  --source-ranges 10.240.0.0/24,10.200.0.0/16
  • Create a firewall rule that allows external SSH, ICMP, and HTTPS:
$ gcloud compute firewall-rules create kubernetes-the-hard-way-allow-external \
  --allow tcp:22,tcp:6443,icmp \
  --network kubernetes-the-hard-way \
  --source-ranges 0.0.0.0/0

Note: An external load balancer will be used to expose the Kubernetes API Servers to remote clients.

  • List the firewall rules in the kubernetes-the-hard-way VPC network:
$ gcloud compute firewall-rules list --filter="network:kubernetes-the-hard-way"
NAME                                    NETWORK                  DIRECTION  PRIORITY  ALLOW                 DENY  DISABLED
kubernetes-the-hard-way-allow-external  kubernetes-the-hard-way  INGRESS    1000      tcp:22,tcp:6443,icmp        False
kubernetes-the-hard-way-allow-internal  kubernetes-the-hard-way  INGRESS    1000      tcp,udp,icmp                False
Kubernetes public IP address
  • Allocate a static IP address that will be attached to the external load balancer fronting the Kubernetes API Servers:
$ gcloud compute addresses create kubernetes-the-hard-way \
  --region $(gcloud config get-value compute/region)
  • Verify that the kubernetes-the-hard-way static IP address was created in your default compute region:
$ gcloud compute addresses list --filter="name=('kubernetes-the-hard-way')"
NAME                     ADDRESS/RANGE  TYPE      PURPOSE  NETWORK  REGION    SUBNET  STATUS
kubernetes-the-hard-way  XX.XX.XX.XX    EXTERNAL                    us-west1          RESERVED

Compute instances

The compute instances will be provisioned using Ubuntu Server 18.04, which has good support for the containerd container runtime. Each compute instance will be provisioned with a fixed private IP address to simplify the Kubernetes bootstrapping process.

Kubernetes Controllers
  • Create three compute instances, which will host the Kubernetes control plane:
for i in 0 1 2; do
  gcloud compute instances create controller-${i} \
    --async \
    --boot-disk-size 200GB \
    --can-ip-forward \
    --image-family ubuntu-1804-lts \
    --image-project ubuntu-os-cloud \
    --machine-type n1-standard-1 \
    --private-network-ip 10.240.0.1${i} \
    --scopes compute-rw,storage-ro,service-management,service-control,logging-write,monitoring \
    --subnet kubernetes \
    --tags kubernetes-the-hard-way,controller
done
Kubernetes Workers

Each worker instance requires a pod subnet allocation from the Kubernetes cluster CIDR range. The pod subnet allocation will be used to configure container networking further down. The pod-cidr instance metadata will be used to expose pod subnet allocations to compute instances at runtime.

Note: The Kubernetes cluster CIDR range is defined by the Controller Manager's --cluster-cidr flag. The cluster CIDR range will be set to 10.200.0.0/16, which supports 254 subnets.

  • Create three compute instances, which will host the Kubernetes worker nodes:
for i in 0 1 2; do
  gcloud compute instances create worker-${i} \
    --async \
    --boot-disk-size 200GB \
    --can-ip-forward \
    --image-family ubuntu-1804-lts \
    --image-project ubuntu-os-cloud \
    --machine-type n1-standard-1 \
    --metadata pod-cidr=10.200.${i}.0/24 \
    --private-network-ip 10.240.0.2${i} \
    --scopes compute-rw,storage-ro,service-management,service-control,logging-write,monitoring \
    --subnet kubernetes \
    --tags kubernetes-the-hard-way,worker
done
Verification
  • List the compute instances in your default compute zone:
$ gcloud compute instances list --filter="tags:kubernetes-the-hard-way"
NAME          ZONE        MACHINE_TYPE   PREEMPTIBLE  INTERNAL_IP  EXTERNAL_IP  STATUS
controller-0  us-west1-a  n1-standard-1               10.240.0.10  XX.XX.XX.XX  RUNNING
controller-1  us-west1-a  n1-standard-1               10.240.0.11  XX.XX.XX.XX  RUNNING
controller-2  us-west1-a  n1-standard-1               10.240.0.12  XX.XX.XX.XX  RUNNING
worker-0      us-west1-a  n1-standard-1               10.240.0.20  XX.XX.XX.XX  RUNNING
worker-1      us-west1-a  n1-standard-1               10.240.0.21  XX.XX.XX.XX  RUNNING
worker-2      us-west1-a  n1-standard-1               10.240.0.22  XX.XX.XX.XX  RUNNING
  • SSH into the instances:
$ gcloud compute ssh controller-0

Provisioning a CA and Generating TLS Certificates

In this section, we will provision a PKI Infrastructure using CloudFlare's PKI toolkit, cfssl (which we installed above), then use it to bootstrap a Certificate Authority, and generate TLS certificates for the following components: etcd, kube-apiserver, kube-controller-manager, kube-scheduler, kubelet, and kube-proxy.

Certificate Authority

Provision a Certificate Authority that can be used to generate additional TLS certificates.

  • Generate the CA configuration file, certificate, and private key:
{

cat > ca-config.json <<EOF
{
  "signing": {
    "default": {
      "expiry": "8760h"
    },
    "profiles": {
      "kubernetes": {
        "usages": ["signing", "key encipherment", "server auth", "client auth"],
        "expiry": "8760h"
      }
    }
  }
}
EOF

cat > ca-csr.json <<EOF
{
  "CN": "Kubernetes",
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "US",
      "L": "Seattle",
      "O": "Kubernetes",
      "OU": "CA",
      "ST": "Washington"
    }
  ]
}
EOF

cfssl gencert -initca ca-csr.json | cfssljson -bare ca

}
  • Results:
ca-key.pem
ca.pem

Client and Server Certificates

In this section, we will generate client and server certificates for each Kubernetes component and a client certificate for the Kubernetes admin user.

The Admin Client Certificate
  • Generate the admin client certificate and private key:
{

cat > admin-csr.json <<EOF
{
  "CN": "admin",
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "US",
      "L": "Seattle",
      "O": "system:masters",
      "OU": "Kubernetes The Hard Way",
      "ST": "Washington"
    }
  ]
}
EOF

cfssl gencert \
  -ca=ca.pem \
  -ca-key=ca-key.pem \
  -config=ca-config.json \
  -profile=kubernetes \
  admin-csr.json | cfssljson -bare admin

}
  • Results:
admin-key.pem
admin.pem
The Kubelet Client Certificates

Kubernetes uses a special-purpose authorization mode called "Node Authorizer", which specifically authorizes API requests made by Kubelets. In order to be authorized by the Node Authorizer, Kubelets must use a credential that identifies them as being in the system:nodes group, with a username of system:node:<nodeName>. In this section, we will create a certificate for each Kubernetes worker node that meets the Node Authorizer requirements.

  • Generate a certificate and private key for each Kubernetes worker node:
for instance in worker-0 worker-1 worker-2; do
cat > ${instance}-csr.json <<EOF
{
  "CN": "system:node:${instance}",
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "US",
      "L": "Seattle",
      "O": "system:nodes",
      "OU": "Kubernetes The Hard Way",
      "ST": "Washington"
    }
  ]
}
EOF

EXTERNAL_IP=$(gcloud compute instances describe ${instance} \
  --format 'value(networkInterfaces[0].accessConfigs[0].natIP)')

INTERNAL_IP=$(gcloud compute instances describe ${instance} \
  --format 'value(networkInterfaces[0].networkIP)')

cfssl gencert \
  -ca=ca.pem \
  -ca-key=ca-key.pem \
  -config=ca-config.json \
  -hostname=${instance},${EXTERNAL_IP},${INTERNAL_IP} \
  -profile=kubernetes \
  ${instance}-csr.json | cfssljson -bare ${instance}
done
  • Results:
worker-0-key.pem
worker-0.pem
worker-1-key.pem
worker-1.pem
worker-2-key.pem
worker-2.pem
The Controller Manager Client Certificate
  • Generate the kube-controller-manager client certificate and private key:
{

cat > kube-controller-manager-csr.json <<EOF
{
  "CN": "system:kube-controller-manager",
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "US",
      "L": "Seattle",
      "O": "system:kube-controller-manager",
      "OU": "Kubernetes The Hard Way",
      "ST": "Washington"
    }
  ]
}
EOF

cfssl gencert \
  -ca=ca.pem \
  -ca-key=ca-key.pem \
  -config=ca-config.json \
  -profile=kubernetes \
  kube-controller-manager-csr.json | cfssljson -bare kube-controller-manager

}
  • Results:
kube-controller-manager-key.pem
kube-controller-manager.pem
The Kube Proxy Client Certificate
  • Generate the kube-proxy client certificate and private key:
{

cat > kube-proxy-csr.json <<EOF
{
  "CN": "system:kube-proxy",
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "US",
      "L": "Seattle",
      "O": "system:node-proxier",
      "OU": "Kubernetes The Hard Way",
      "ST": "Washington"
    }
  ]
}
EOF

cfssl gencert \
  -ca=ca.pem \
  -ca-key=ca-key.pem \
  -config=ca-config.json \
  -profile=kubernetes \
  kube-proxy-csr.json | cfssljson -bare kube-proxy

}
  • Results:
kube-proxy-key.pem
kube-proxy.pem
The Scheduler Client Certificate
  • Generate the kube-scheduler client certificate and private key:
{

cat > kube-scheduler-csr.json <<EOF
{
  "CN": "system:kube-scheduler",
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "US",
      "L": "Seattle",
      "O": "system:kube-scheduler",
      "OU": "Kubernetes The Hard Way",
      "ST": "Washington"
    }
  ]
}
EOF

cfssl gencert \
  -ca=ca.pem \
  -ca-key=ca-key.pem \
  -config=ca-config.json \
  -profile=kubernetes \
  kube-scheduler-csr.json | cfssljson -bare kube-scheduler

}
  • Results:
kube-scheduler-key.pem
kube-scheduler.pem
The Kubernetes API Server Certificate

The kubernetes-the-hard-way static IP address will be included in the list of subject alternative names for the Kubernetes API Server certificate. This will ensure the certificate can be validated by remote clients.

  • Generate the Kubernetes API Server certificate and private key:
{

KUBERNETES_PUBLIC_ADDRESS=$(gcloud compute addresses describe kubernetes-the-hard-way \
  --region $(gcloud config get-value compute/region) \
  --format 'value(address)')

cat > kubernetes-csr.json <<EOF
{
  "CN": "kubernetes",
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "US",
      "L": "Seattle",
      "O": "Kubernetes",
      "OU": "Kubernetes The Hard Way",
      "ST": "Washington"
    }
  ]
}
EOF

cfssl gencert \
  -ca=ca.pem \
  -ca-key=ca-key.pem \
  -config=ca-config.json \
  -hostname=10.32.0.1,10.240.0.10,10.240.0.11,10.240.0.12,${KUBERNETES_PUBLIC_ADDRESS},127.0.0.1,kubernetes.default \
  -profile=kubernetes \
  kubernetes-csr.json | cfssljson -bare kubernetes

}
  • Results:
kubernetes-key.pem
kubernetes.pem
The Service Account Key Pair

The Kubernetes Controller Manager leverages a key pair to generate and sign service account tokens as described in the managing service accounts documentation.

  • Generate the service-account certificate and private key:
{

cat > service-account-csr.json <<EOF
{
  "CN": "service-accounts",
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "US",
      "L": "Seattle",
      "O": "Kubernetes",
      "OU": "Kubernetes The Hard Way",
      "ST": "Washington"
    }
  ]
}
EOF

cfssl gencert \
  -ca=ca.pem \
  -ca-key=ca-key.pem \
  -config=ca-config.json \
  -profile=kubernetes \
  service-account-csr.json | cfssljson -bare service-account

}
  • Results:
service-account-key.pem
service-account.pem
Distribute the Client and Server Certificates
  • Copy the appropriate certificates and private keys to each worker instance:
for instance in worker-0 worker-1 worker-2; do
  gcloud compute scp ca.pem ${instance}-key.pem ${instance}.pem ${instance}:~/
done
  • Copy the appropriate certificates and private keys to each controller instance:
for instance in controller-0 controller-1 controller-2; do
  gcloud compute scp ca.pem ca-key.pem kubernetes-key.pem kubernetes.pem \
    service-account-key.pem service-account.pem ${instance}:~/
done

Note: The kube-proxy, kube-controller-manager, kube-scheduler, and kubelet client certificates will be used to generate client authentication configuration files in the next section.

Generating Kubernetes Configuration Files for Authentication

In this section, we will generate Kubernetes configuration files, also known as kubeconfigs, which enable Kubernetes clients to locate and authenticate to the Kubernetes API Servers.

Client Authentication Configs

In this section, we will generate kubeconfig files for the controller manager, kubelet, kube-proxy, and scheduler clients and the admin user.

Kubernetes Public IP Address

Each kubeconfig requires a Kubernetes API Server to connect to. To support high availability the IP address assigned to the external load balancer fronting the Kubernetes API Servers will be used.

  • Retrieve the kubernetes-the-hard-way static IP address:
KUBERNETES_PUBLIC_ADDRESS=$(gcloud compute addresses describe kubernetes-the-hard-way \
  --region $(gcloud config get-value compute/region) \
  --format 'value(address)')
The kubelet Kubernetes Configuration File

When generating kubeconfig files for Kubelets the client certificate matching the Kubelet's node name must be used. This will ensure Kubelets are properly authorized by the Kubernetes Node Authorizer.

  • Generate a kubeconfig file for each worker node:
for instance in worker-0 worker-1 worker-2; do
  kubectl config set-cluster kubernetes-the-hard-way \
    --certificate-authority=ca.pem \
    --embed-certs=true \
    --server=https://${KUBERNETES_PUBLIC_ADDRESS}:6443 \
    --kubeconfig=${instance}.kubeconfig

  kubectl config set-credentials system:node:${instance} \
    --client-certificate=${instance}.pem \
    --client-key=${instance}-key.pem \
    --embed-certs=true \
    --kubeconfig=${instance}.kubeconfig

  kubectl config set-context default \
    --cluster=kubernetes-the-hard-way \
    --user=system:node:${instance} \
    --kubeconfig=${instance}.kubeconfig

  kubectl config use-context default --kubeconfig=${instance}.kubeconfig
done
  • Results:
worker-0.kubeconfig
worker-1.kubeconfig
worker-2.kubeconfig
The kube-proxy Kubernetes Configuration File
  • Generate a kubeconfig file for the kube-proxy service:
{
  kubectl config set-cluster kubernetes-the-hard-way \
    --certificate-authority=ca.pem \
    --embed-certs=true \
    --server=https://${KUBERNETES_PUBLIC_ADDRESS}:6443 \
    --kubeconfig=kube-proxy.kubeconfig

  kubectl config set-credentials system:kube-proxy \
    --client-certificate=kube-proxy.pem \
    --client-key=kube-proxy-key.pem \
    --embed-certs=true \
    --kubeconfig=kube-proxy.kubeconfig

  kubectl config set-context default \
    --cluster=kubernetes-the-hard-way \
    --user=system:kube-proxy \
    --kubeconfig=kube-proxy.kubeconfig

  kubectl config use-context default --kubeconfig=kube-proxy.kubeconfig
}
  • Results:
kube-proxy.kubeconfig
The kube-controller-manager Kubernetes Configuration File
  • Generate a kubeconfig file for the kube-controller-manager service:
{
  kubectl config set-cluster kubernetes-the-hard-way \
    --certificate-authority=ca.pem \
    --embed-certs=true \
    --server=https://127.0.0.1:6443 \
    --kubeconfig=kube-controller-manager.kubeconfig

  kubectl config set-credentials system:kube-controller-manager \
    --client-certificate=kube-controller-manager.pem \
    --client-key=kube-controller-manager-key.pem \
    --embed-certs=true \
    --kubeconfig=kube-controller-manager.kubeconfig

  kubectl config set-context default \
    --cluster=kubernetes-the-hard-way \
    --user=system:kube-controller-manager \
    --kubeconfig=kube-controller-manager.kubeconfig

  kubectl config use-context default --kubeconfig=kube-controller-manager.kubeconfig
}
  • Results:
kube-controller-manager.kubeconfig
The kube-scheduler Kubernetes Configuration File
  • Generate a kubeconfig file for the kube-scheduler service:
{
  kubectl config set-cluster kubernetes-the-hard-way \
    --certificate-authority=ca.pem \
    --embed-certs=true \
    --server=https://127.0.0.1:6443 \
    --kubeconfig=kube-scheduler.kubeconfig

  kubectl config set-credentials system:kube-scheduler \
    --client-certificate=kube-scheduler.pem \
    --client-key=kube-scheduler-key.pem \
    --embed-certs=true \
    --kubeconfig=kube-scheduler.kubeconfig

  kubectl config set-context default \
    --cluster=kubernetes-the-hard-way \
    --user=system:kube-scheduler \
    --kubeconfig=kube-scheduler.kubeconfig

  kubectl config use-context default --kubeconfig=kube-scheduler.kubeconfig
}
  • Results:
kube-scheduler.kubeconfig
The admin Kubernetes Configuration File
  • Generate a kubeconfig file for the admin user:
{
  kubectl config set-cluster kubernetes-the-hard-way \
    --certificate-authority=ca.pem \
    --embed-certs=true \
    --server=https://127.0.0.1:6443 \
    --kubeconfig=admin.kubeconfig

  kubectl config set-credentials admin \
    --client-certificate=admin.pem \
    --client-key=admin-key.pem \
    --embed-certs=true \
    --kubeconfig=admin.kubeconfig

  kubectl config set-context default \
    --cluster=kubernetes-the-hard-way \
    --user=admin \
    --kubeconfig=admin.kubeconfig

  kubectl config use-context default --kubeconfig=admin.kubeconfig
}
  • Results:
admin.kubeconfig

Distribute the Kubernetes Configuration Files

  • Copy the appropriate kubelet and kube-proxy kubeconfig files to each worker instance:
for instance in worker-0 worker-1 worker-2; do
  gcloud compute scp ${instance}.kubeconfig kube-proxy.kubeconfig ${instance}:~/
done
  • Copy the appropriate kube-controller-manager and kube-scheduler kubeconfig files to each controller instance:
for instance in controller-0 controller-1 controller-2; do
  gcloud compute scp admin.kubeconfig kube-controller-manager.kubeconfig kube-scheduler.kubeconfig ${instance}:~/
done

Generating the Data Encryption Config and Key

Kubernetes stores a variety of data including cluster state, application configurations, and secrets. Kubernetes supports the ability to encrypt cluster data at rest.

In this section, we will generate an encryption key and an encryption config suitable for encrypting Kubernetes Secrets.

  • Create the encryption-config.yaml encryption config file:
cat > encryption-config.yaml <<EOF
kind: EncryptionConfig
apiVersion: v1
resources:
  - resources:
      - secrets
    providers:
      - aescbc:
          keys:
            - name: key1
              secret: $(head -c 32 /dev/urandom | base64 -i -)
      - identity: {}
EOF
  • Copy the encryption-config.yaml encryption config file to each controller instance:
for instance in controller-0 controller-1 controller-2; do
  gcloud compute scp encryption-config.yaml ${instance}:~/
done

Bootstrapping the etcd Cluster

Kubernetes components are stateless and store cluster state in etcd. In this section, we will bootstrap a three-node etcd cluster and configure it for high availability and secure remote access.

Prerequisites

The commands in this section must be run on each controller instance: controller-0, controller-1, and controller-2.

Using tmux, split your shell into 3 x panes (ctrl + b ") and then log into each controller instance: 

$ gcloud compute ssh controller-0
ctrl + b o
$ gcloud compute ssh controller-1
ctrl + b o
$ gcloud compute ssh controller-2

Now, set tmux to run all subsequent commands (unless otherwise stated) in parallel on all 3 x controller instances (in all 3 x tmux panes): 

ctrl + b :
set synchronize-panes on # off
#~OR~
setw synchronize-panes # toggles on/off
Download and Install the etcd Binaries

Download the official etcd release binaries from the coreos/etcd GitHub project: 

ETCD_VER=v3.3.13
# choose either URL
GOOGLE_URL=https://storage.googleapis.com/etcd
GITHUB_URL=https://github.com/etcd-io/etcd/releases/download
DOWNLOAD_URL=${GOOGLE_URL}

wget -q --show-progress --https-only --timestamping \
  "${DOWNLOAD_URL}/${ETCD_VER}/etcd-${ETCD_VER}-linux-amd64.tar.gz"
  • Extract and install the etcd server and the etcdctl command line utility:
{
  tar -xvf etcd-${ETCD_VER}-linux-amd64.tar.gz
  sudo mv etcd-${ETCD_VER}-linux-amd64/etcd* /usr/local/bin/
  rm -rf etcd-${ETCD_VER}-linux-amd64*
}
Configure the etcd Server
{
  sudo mkdir -p /etc/etcd /var/lib/etcd
  sudo cp ca.pem kubernetes-key.pem kubernetes.pem /etc/etcd/
}

The instance internal IP address will be used to serve client requests and communicate with etcd cluster peers.

  • Retrieve the internal IP address for the current compute instance:
INTERNAL_IP=$(curl -s -H "Metadata-Flavor: Google" \
  http://metadata.google.internal/computeMetadata/v1/instance/network-interfaces/0/ip)

Each etcd member must have a unique name within an etcd cluster. Set the etcd name to match the hostname of the current compute instance: 

$ ETCD_NAME=$(hostname -s)
  • Create the etcd.service systemd unit file:
cat <<EOF | sudo tee /etc/systemd/system/etcd.service
[Unit]
Description=etcd
Documentation=https://github.com/coreos

[Service]
ExecStart=/usr/local/bin/etcd \\
  --name ${ETCD_NAME} \\
  --cert-file=/etc/etcd/kubernetes.pem \\
  --key-file=/etc/etcd/kubernetes-key.pem \\
  --peer-cert-file=/etc/etcd/kubernetes.pem \\
  --peer-key-file=/etc/etcd/kubernetes-key.pem \\
  --trusted-ca-file=/etc/etcd/ca.pem \\
  --peer-trusted-ca-file=/etc/etcd/ca.pem \\
  --peer-client-cert-auth \\
  --client-cert-auth \\
  --initial-advertise-peer-urls https://${INTERNAL_IP}:2380 \\
  --listen-peer-urls https://${INTERNAL_IP}:2380 \\
  --listen-client-urls https://${INTERNAL_IP}:2379,https://127.0.0.1:2379 \\
  --advertise-client-urls https://${INTERNAL_IP}:2379 \\
  --initial-cluster-token etcd-cluster-0 \\
  --initial-cluster controller-0=https://10.240.0.10:2380,controller-1=https://10.240.0.11:2380,controller-2=https://10.240.0.12:2380 \\
  --initial-cluster-state new \\
  --data-dir=/var/lib/etcd
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target
EOF
Start the etcd Server
{
  sudo systemctl daemon-reload
  sudo systemctl enable etcd
  sudo systemctl start etcd
}

Remember to run the above commands on each controller node: controller-0, controller-1, and controller-2.

Verification
  • List the etcd cluster members:
$ sudo ETCDCTL_API=3 etcdctl member list \
  --endpoints=https://127.0.0.1:2379 \
  --cacert=/etc/etcd/ca.pem \
  --cert=/etc/etcd/kubernetes.pem \
  --key=/etc/etcd/kubernetes-key.pem

3a57933972cb5131, started, controller-2, https://10.240.0.12:2380, https://10.240.0.12:2379
f98dc20bce6225a0, started, controller-0, https://10.240.0.10:2380, https://10.240.0.10:2379
ffed16798470cab5, started, controller-1, https://10.240.0.11:2380, https://10.240.0.11:2379

Bootstrapping the Kubernetes Control Plane

In this section, we will bootstrap the Kubernetes control plane across three compute instances and configure it for high availability. We will also create an external load balancer that exposes the Kubernetes API Servers to remote clients. The following components will be installed on each node: Kubernetes API Server, Scheduler, and Controller Manager.

Prerequisites

The commands in this section must be run on each controller instance: controller-0, controller-1, and controller-2.

Using tmux, split your shell into 3 x panes (ctrl + b ") and then log into each controller instance: 

$ gcloud compute ssh controller-0
ctrl + b o
$ gcloud compute ssh controller-1
ctrl + b o
$ gcloud compute ssh controller-2

Now, set tmux to run all subsequent commands (unless otherwise stated) in parallel on all 3 x controller instances (in all 3 x tmux panes): 

ctrl + b :
set synchronize-panes on # off
#~OR~
setw synchronize-panes # toggles on/off

Provision the Kubernetes Control Plane

  • Create the Kubernetes configuration directory:
$ sudo mkdir -p /etc/kubernetes/config
Download and Install the Kubernetes Controller Binaries
  • Download the official Kubernetes release binaries:
$ K8S_VERSION=$(curl -sSL https://dl.k8s.io/release/stable.txt)
$ K8S_URL=https://storage.googleapis.com/kubernetes-release/release/${K8S_VERSION}/bin/linux/amd64
$ wget -q --show-progress --https-only --timestamping \
  "${K8S_URL}/kube-apiserver" \
  "${K8S_URL}/kube-controller-manager" \
  "${K8S_URL}/kube-scheduler" \
  "${K8S_URL}/kubectl"
  • Install the Kubernetes binaries:
{
  chmod +x kube-apiserver kube-controller-manager kube-scheduler kubectl
  sudo mv kube-apiserver kube-controller-manager kube-scheduler kubectl /usr/local/bin/
}

Configure the Kubernetes API Server

{
  sudo mkdir -p /var/lib/kubernetes/

  sudo mv ca.pem ca-key.pem kubernetes-key.pem kubernetes.pem \
    service-account-key.pem service-account.pem \
    encryption-config.yaml /var/lib/kubernetes/

  sudo chmod 0600 /var/lib/kubernetes/encryption-config.yaml
}

The instance internal IP address will be used to advertise the API Server to members of the cluster.

  • Retrieve the internal IP address for the current compute instance:
INTERNAL_IP=$(curl -s -H "Metadata-Flavor: Google" \
  http://metadata.google.internal/computeMetadata/v1/instance/network-interfaces/0/ip)
  • Create the kube-apiserver.service systemd unit file:
cat <<EOF | sudo tee /etc/systemd/system/kube-apiserver.service
[Unit]
Description=Kubernetes API Server
Documentation=https://github.com/kubernetes/kubernetes

[Service]
ExecStart=/usr/local/bin/kube-apiserver \\
  --advertise-address=${INTERNAL_IP} \\
  --allow-privileged=true \\
  --apiserver-count=3 \\
  --audit-log-maxage=30 \\
  --audit-log-maxbackup=3 \\
  --audit-log-maxsize=100 \\
  --audit-log-path=/var/log/audit.log \\
  --authorization-mode=Node,RBAC \\
  --bind-address=0.0.0.0 \\
  --client-ca-file=/var/lib/kubernetes/ca.pem \\
  --enable-admission-plugins=NamespaceLifecycle,NodeRestriction,LimitRanger,ServiceAccount,DefaultStorageClass,ResourceQuota \\
  --etcd-cafile=/var/lib/kubernetes/ca.pem \\
  --etcd-certfile=/var/lib/kubernetes/kubernetes.pem \\
  --etcd-keyfile=/var/lib/kubernetes/kubernetes-key.pem \\
  --etcd-servers=https://10.240.0.10:2379,https://10.240.0.11:2379,https://10.240.0.12:2379 \\
  --event-ttl=1h \\
  --encryption-provider-config=/var/lib/kubernetes/encryption-config.yaml \\
  --kubelet-certificate-authority=/var/lib/kubernetes/ca.pem \\
  --kubelet-client-certificate=/var/lib/kubernetes/kubernetes.pem \\
  --kubelet-client-key=/var/lib/kubernetes/kubernetes-key.pem \\
  --kubelet-https=true \\
  --runtime-config=api/all \\
  --service-account-key-file=/var/lib/kubernetes/service-account.pem \\
  --service-cluster-ip-range=10.32.0.0/24 \\
  --service-node-port-range=30000-32767 \\
  --tls-cert-file=/var/lib/kubernetes/kubernetes.pem \\
  --tls-private-key-file=/var/lib/kubernetes/kubernetes-key.pem \\
  --v=2
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target
EOF

Configure the Kubernetes Controller Manager

  • Move the kube-controller-manager kubeconfig into place:
sudo mv kube-controller-manager.kubeconfig /var/lib/kubernetes/
  • Create the kube-controller-manager.service systemd unit file:
cat <<EOF | sudo tee /etc/systemd/system/kube-controller-manager.service
[Unit]
Description=Kubernetes Controller Manager
Documentation=https://github.com/kubernetes/kubernetes

[Service]
ExecStart=/usr/local/bin/kube-controller-manager \\
  --address=0.0.0.0 \\
  --cluster-cidr=10.200.0.0/16 \\
  --cluster-name=kubernetes \\
  --cluster-signing-cert-file=/var/lib/kubernetes/ca.pem \\
  --cluster-signing-key-file=/var/lib/kubernetes/ca-key.pem \\
  --kubeconfig=/var/lib/kubernetes/kube-controller-manager.kubeconfig \\
  --leader-elect=true \\
  --root-ca-file=/var/lib/kubernetes/ca.pem \\
  --service-account-private-key-file=/var/lib/kubernetes/service-account-key.pem \\
  --service-cluster-ip-range=10.32.0.0/24 \\
  --use-service-account-credentials=true \\
  --v=2
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target
EOF

Configure the Kubernetes Scheduler

  • Move the kube-scheduler kubeconfig into place:
$ sudo mv kube-scheduler.kubeconfig /var/lib/kubernetes/
  • Create the kube-scheduler.yaml configuration file:
cat <<EOF | sudo tee /etc/kubernetes/config/kube-scheduler.yaml
apiVersion: kubescheduler.config.k8s.io/v1alpha1
kind: KubeSchedulerConfiguration
clientConnection:
  kubeconfig: "/var/lib/kubernetes/kube-scheduler.kubeconfig"
leaderElection:
  leaderElect: true
EOF
  • Create the kube-scheduler.service systemd unit file:
cat <<EOF | sudo tee /etc/systemd/system/kube-scheduler.service
[Unit]
Description=Kubernetes Scheduler
Documentation=https://github.com/kubernetes/kubernetes

[Service]
ExecStart=/usr/local/bin/kube-scheduler \\
  --config=/etc/kubernetes/config/kube-scheduler.yaml \\
  --v=2
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target
EOF

Start the Controller Services

{
  sudo systemctl daemon-reload
  sudo systemctl enable kube-apiserver kube-controller-manager kube-scheduler
  sudo systemctl start kube-apiserver kube-controller-manager kube-scheduler
}

Allow up to 10 seconds for the Kubernetes API Server to fully initialize.

Enable HTTP Health Checks

A Google Network Load Balancer will be used to distribute traffic across the three API servers and allow each API server to terminate TLS connections and validate client certificates. The network load balancer only supports HTTP health checks which means the HTTPS endpoint exposed by the API server cannot be used. As a workaround, an Nginx webserver can be used to proxy HTTP health checks. In this section, Nginx will be installed and configured to accept HTTP health checks on port 80 and proxy the connections to the API server on https://127.0.0.1:6443/healthz.

The /healthz API server endpoint does not require authentication by default.

  • Install a basic webserver to handle HTTP health checks:
$ sudo apt-get install -y nginx

$ cat > kubernetes.default.svc.cluster.local <<EOF
server {
  listen 80;
  server_name kubernetes.default.svc.cluster.local;

  location /healthz {
     proxy_pass https://127.0.0.1:6443/healthz;
     proxy_ssl_trusted_certificate /var/lib/kubernetes/ca.pem;
  }
}
EOF

{
  sudo mv kubernetes.default.svc.cluster.local \
    /etc/nginx/sites-available/kubernetes.default.svc.cluster.local

  sudo ln -s /etc/nginx/sites-available/kubernetes.default.svc.cluster.local \
    /etc/nginx/sites-enabled/
}

$ sudo systemctl restart nginx && sudo systemctl enable nginx

Verification

$ kubectl get componentstatuses --kubeconfig admin.kubeconfig
NAME                 STATUS    MESSAGE              ERROR
controller-manager   Healthy   ok
scheduler            Healthy   ok
etcd-2               Healthy   {"health": "true"}
etcd-0               Healthy   {"health": "true"}
etcd-1               Healthy   {"health": "true"}
  • Test the nginx HTTP health check proxy:
$ curl -H "Host: kubernetes.default.svc.cluster.local" -i http://127.0.0.1/healthz
HTTP/1.1 200 OK
Server: nginx/1.14.0 (Ubuntu)
Date: Sun, 30 Sep 2018 17:44:24 GMT
Content-Type: text/plain; charset=utf-8
Content-Length: 2
Connection: keep-alive

ok

Note: Remember to run the above commands on each controller node: controller-0, controller-1, and controller-2.

RBAC for Kubelet Authorization

In this section, we will configure Role-Based Access Control (RBAC) permissions to allow the Kubernetes API Server to access the Kubelet API on each worker node. Access to the Kubelet API is required for retrieving metrics, logs, and executing commands in pods.

Note: We are also setting the Kubelet --authorization-mode flag to Webhook. Webhook mode uses the SubjectAccessReview API to determine authorization.

  • SSH into just the controller-0 instance:
$ gcloud compute ssh controller-0
  • Create the system:kube-apiserver-to-kubelet ClusterRole with permissions to access the Kubelet API and perform most common tasks associated with managing pods:
cat <<EOF | kubectl apply --kubeconfig admin.kubeconfig -f -
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRole
metadata:
  annotations:
    rbac.authorization.kubernetes.io/autoupdate: "true"
  labels:
    kubernetes.io/bootstrapping: rbac-defaults
  name: system:kube-apiserver-to-kubelet
rules:
  - apiGroups:
      - ""
    resources:
      - nodes/proxy
      - nodes/stats
      - nodes/log
      - nodes/spec
      - nodes/metrics
    verbs:
      - "*"
EOF

The Kubernetes API Server authenticates to the Kubelet as the kubernetes user using the client certificate as defined by the --kubelet-client-certificate flag.

  • Bind the system:kube-apiserver-to-kubelet ClusterRole to the kubernetes user:
cat <<EOF | kubectl apply --kubeconfig admin.kubeconfig -f -
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
  name: system:kube-apiserver
  namespace: ""
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: system:kube-apiserver-to-kubelet
subjects:
  - apiGroup: rbac.authorization.k8s.io
    kind: User
    name: kubernetes
EOF

The Kubernetes Frontend Load Balancer

In this section, we will provision an external load balancer to front the Kubernetes API Servers. The kubernetes-the-hard-way static IP address (created above) will be attached to the resulting load balancer.

Note: The compute instances created in this article will not have permission to complete this section. Run the following commands from the same machine used to create the compute instances.

Rules for Network Load Balancing

When we create our external load balancer, we need to create an ingress firewall rule for Network Load Balancing, which requires a legacy health check. The source IP ranges for legacy health checks for Network Load Balancing are: 

35.191.0.0/16
209.85.152.0/22
209.85.204.0/22
Provision a Network Load Balancer
  • Create the external load balancer network resources:
{
  KUBERNETES_PUBLIC_ADDRESS=$(gcloud compute addresses describe kubernetes-the-hard-way \
    --region $(gcloud config get-value compute/region) \
    --format 'value(address)')

  gcloud compute http-health-checks create kubernetes \
    --description "Kubernetes Health Check" \
    --host "kubernetes.default.svc.cluster.local" \
    --request-path "/healthz"

  gcloud compute firewall-rules create kubernetes-the-hard-way-allow-health-check \
    --network kubernetes-the-hard-way \
    --source-ranges 209.85.152.0/22,209.85.204.0/22,35.191.0.0/16 \
    --allow tcp

  gcloud compute target-pools create kubernetes-target-pool \
    --http-health-check kubernetes

  gcloud compute target-pools add-instances kubernetes-target-pool \
   --instances controller-0,controller-1,controller-2

  gcloud compute forwarding-rules create kubernetes-forwarding-rule \
    --address ${KUBERNETES_PUBLIC_ADDRESS} \
    --ports 6443 \
    --region $(gcloud config get-value compute/region) \
    --target-pool kubernetes-target-pool
}
  • Get some basic information on our external load balancer:
$ gcloud compute target-pools list --filter="name:kubernetes-target-pool"
NAME                    REGION    SESSION_AFFINITY  BACKUP  HEALTH_CHECKS
kubernetes-target-pool  us-west1  NONE                      kubernetes

Note: In the GCP API, there is no direct "load balancer" entity; just a collection of components that constitute the load balancer.

Verification

  • Retrieve the kubernetes-the-hard-way static IP address:
KUBERNETES_PUBLIC_ADDRESS=$(gcloud compute addresses describe kubernetes-the-hard-way \
  --region $(gcloud config get-value compute/region) \
  --format 'value(address)')
  • Make an HTTP request for the Kubernetes version info:
$ curl --cacert ca.pem https://${KUBERNETES_PUBLIC_ADDRESS}:6443/version

{
  "major": "1",
  "minor": "15",
  "gitVersion": "v1.15.2",
  "gitCommit": "f6278300bebbb750328ac16ee6dd3aa7d3549568",
  "gitTreeState": "clean",
  "buildDate": "2019-08-05T09:15:22Z",
  "goVersion": "go1.12.5",
  "compiler": "gc",
  "platform": "linux/amd64"
}

Bootstrapping the Kubernetes Worker Nodes

In this section, we will bootstrap three Kubernetes worker nodes. The following components will be installed on each node:

Prerequisites

The commands in this section must be run on each worker instance/node: worker-0, worker-1, and worker-2.

Using tmux, split your shell into 3 x panes (ctrl + b ") and then log into each worker instance: 

$ gcloud compute ssh worker-0
ctrl + b o
$ gcloud compute ssh worker-1
ctrl + b o
$ gcloud compute ssh worker-2

Now, set tmux to run all subsequent commands (unless otherwise stated) in parallel on all 3 x controller instances (in all 3 x tmux panes): 

ctrl + b :
set synchronize-panes on # off
#~OR~
setw synchronize-panes # toggles on/off

Provisioning a Kubernetes Worker Node

  • Install the OS dependencies:
{
  sudo apt-get update
  sudo apt-get -y install socat conntrack ipset
}

Note: The socat binary enables support for the kubectl port-forward command.

Download and Install Worker Binaries
  • Create the installation directories:
$ sudo mkdir -p \
    /etc/cni/net.d \
    /opt/cni/bin \
    /var/lib/kubelet \
    /var/lib/kube-proxy \
    /var/lib/kubernetes \
    /var/run/kubernetes

$ K8S_VERSION=v1.15.2
$ mkdir tar && cd $_
$ wget -q --show-progress --https-only --timestamping \
    "https://github.com/kubernetes-sigs/cri-tools/releases/download/v1.15.0/crictl-v1.15.0-linux-amd64.tar.gz" \
    "https://storage.googleapis.com/kubernetes-the-hard-way/runsc-50c283b9f56bb7200938d9e207355f05f79f0d17" \
    "https://github.com/opencontainers/runc/releases/download/v1.0.0-rc8/runc.amd64" \
    "https://github.com/containernetworking/plugins/releases/download/v0.8.1/cni-plugins-linux-amd64-v0.8.1.tgz" \
    "https://github.com/containerd/containerd/releases/download/v1.2.7/containerd-1.2.7.linux-amd64.tar.gz" \
    "https://storage.googleapis.com/kubernetes-release/release/${K8S_VERSION}/bin/linux/amd64/kubectl" \
    "https://storage.googleapis.com/kubernetes-release/release/${K8S_VERSION}/bin/linux/amd64/kube-proxy" \
    "https://storage.googleapis.com/kubernetes-release/release/${K8S_VERSION}/bin/linux/amd64/kubelet"
  • Install the worker binaries:
cni-plugins-linux-amd64-v0.8.1.tgz
containerd-1.2.7.linux-amd64.tar.gz
crictl-v1.15.0-linux-amd64.tar.gz
kube-proxy
kubectl
kubelet
runc.amd64
runsc-50c283b9f56bb7200938d9e207355f05f79f0d17
{
  sudo mv runsc-50c283b9f56bb7200938d9e207355f05f79f0d17 runsc
  sudo mv runc.amd64 runc
  chmod +x kubectl kube-proxy kubelet runc runsc
  sudo mv kubectl kube-proxy kubelet runc runsc /usr/local/bin/
  sudo tar -xvf crictl-v1.15.0-linux-amd64.tar.gz -C /usr/local/bin/
  sudo tar -xvf cni-plugins-linux-amd64-v0.8.1.tgz -C /opt/cni/bin/
  sudo tar -xvf containerd-1.2.7.linux-amd64.tar.gz -C /
  cd $HOME
}

Configure CNI Networking

  • Retrieve the Pod CIDR range for the current compute instance:
POD_CIDR=$(curl -s -H "Metadata-Flavor: Google" \
  http://metadata.google.internal/computeMetadata/v1/instance/attributes/pod-cidr)
  • Create the bridge network configuration file:
cat <<EOF | sudo tee /etc/cni/net.d/10-bridge.conf
{
    "cniVersion": "0.3.1",
    "name": "bridge",
    "type": "bridge",
    "bridge": "cnio0",
    "isGateway": true,
    "ipMasq": true,
    "ipam": {
        "type": "host-local",
        "ranges": [
          [{"subnet": "${POD_CIDR}"}]
        ],
        "routes": [{"dst": "0.0.0.0/0"}]
    }
}
EOF
  • Create the loopback network configuration file:
cat <<EOF | sudo tee /etc/cni/net.d/99-loopback.conf
{
    "cniVersion": "0.3.1",
    "type": "loopback"
}
EOF

Configure containerd

  • Create the containerd configuration file:
sudo mkdir -p /etc/containerd/

cat << EOF | sudo tee /etc/containerd/config.toml
[plugins]
  [plugins.cri.containerd]
    snapshotter = "overlayfs"
    [plugins.cri.containerd.default_runtime]
      runtime_type = "io.containerd.runtime.v1.linux"
      runtime_engine = "/usr/local/bin/runc"
      runtime_root = ""
    [plugins.cri.containerd.untrusted_workload_runtime]
      runtime_type = "io.containerd.runtime.v1.linux"
      runtime_engine = "/usr/local/bin/runsc"
      runtime_root = "/run/containerd/runsc"
    [plugins.cri.containerd.gvisor]
      runtime_type = "io.containerd.runtime.v1.linux"
      runtime_engine = "/usr/local/bin/runsc"
      runtime_root = "/run/containerd/runsc"
EOF

Note: Untrusted workloads will be run using the gVisor (runsc) runtime.

  • Create the containerd.service systemd unit file:
cat << EOF | sudo tee /etc/systemd/system/containerd.service
[Unit]
Description=containerd container runtime
Documentation=https://containerd.io
After=network.target

[Service]
ExecStartPre=/sbin/modprobe overlay
ExecStart=/bin/containerd
Restart=always
RestartSec=5
Delegate=yes
KillMode=process
OOMScoreAdjust=-999
LimitNOFILE=1048576
LimitNPROC=infinity
LimitCORE=infinity

[Install]
WantedBy=multi-user.target
EOF

Configure the Kubelet

{
  sudo mv ${HOSTNAME}-key.pem ${HOSTNAME}.pem /var/lib/kubelet/
  sudo mv ${HOSTNAME}.kubeconfig /var/lib/kubelet/kubeconfig
  sudo mv ca.pem /var/lib/kubernetes/
}
  • Create the kubelet-config.yaml configuration file:
cat << EOF | sudo tee /var/lib/kubelet/kubelet-config.yaml
kind: KubeletConfiguration
apiVersion: kubelet.config.k8s.io/v1beta1
authentication:
  anonymous:
    enabled: false
  webhook:
    enabled: true
  x509:
    clientCAFile: "/var/lib/kubernetes/ca.pem"
authorization:
  mode: Webhook
clusterDomain: "cluster.local"
clusterDNS:
  - "10.32.0.10"
podCIDR: "${POD_CIDR}"
resolvConf: "/run/systemd/resolve/resolv.conf"
runtimeRequestTimeout: "15m"
tlsCertFile: "/var/lib/kubelet/${HOSTNAME}.pem"
tlsPrivateKeyFile: "/var/lib/kubelet/${HOSTNAME}-key.pem"
EOF

Note: The resolvConf configuration is used to avoid loops when using CoreDNS for service discovery on systems running systemd-resolved.

  • Create the kubelet.service systemd unit file:
cat << EOF | sudo tee /etc/systemd/system/kubelet.service
[Unit]
Description=Kubernetes Kubelet
Documentation=https://github.com/kubernetes/kubernetes
After=containerd.service
Requires=containerd.service

[Service]
ExecStart=/usr/local/bin/kubelet \\
  --config=/var/lib/kubelet/kubelet-config.yaml \\
  --container-runtime=remote \\
  --container-runtime-endpoint=unix:///var/run/containerd/containerd.sock \\
  --image-pull-progress-deadline=2m \\
  --kubeconfig=/var/lib/kubelet/kubeconfig \\
  --network-plugin=cni \\
  --register-node=true \\
  --v=2
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target
EOF

Configure the Kubernetes Proxy

$ sudo mv kube-proxy.kubeconfig /var/lib/kube-proxy/kubeconfig
  • Create the kube-proxy-config.yaml configuration file:
cat << EOF | sudo tee /var/lib/kube-proxy/kube-proxy-config.yaml
kind: KubeProxyConfiguration
apiVersion: kubeproxy.config.k8s.io/v1alpha1
clientConnection:
  kubeconfig: "/var/lib/kube-proxy/kubeconfig"
mode: "iptables"
clusterCIDR: "10.200.0.0/16"
EOF
  • Create the kube-proxy.service systemd unit file:
cat << EOF | sudo tee /etc/systemd/system/kube-proxy.service
[Unit]
Description=Kubernetes Kube Proxy
Documentation=https://github.com/kubernetes/kubernetes

[Service]
ExecStart=/usr/local/bin/kube-proxy \\
  --config=/var/lib/kube-proxy/kube-proxy-config.yaml
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target
EOF

Start the Worker Services

{
  sudo systemctl daemon-reload
  sudo systemctl enable containerd kubelet kube-proxy
  sudo systemctl start containerd kubelet kube-proxy
}

Note: Remember to run the above commands on each worker node: worker-0, worker-1, and worker-2.

  • Check the statuses of the worker services:
$ systemctl status containerd kubelet kube-proxy

Verification

NOTE: The compute instances created in this article will not have permission to complete this section. Run the following commands from the same machine used to create the compute instances.

  • List the registered Kubernetes nodes:
gcloud compute ssh controller-0 \
  --command "kubectl --kubeconfig admin.kubeconfig get nodes -o wide"

NAME       STATUS   ROLES    AGE    VERSION   INTERNAL-IP   EXTERNAL-IP   OS-IMAGE             KERNEL-VERSION    CONTAINER-RUNTIME
worker-0   Ready    <none>   3m3s   v1.15.2   10.240.0.20   <none>        Ubuntu 18.04.2 LTS   4.15.0-1037-gcp   containerd://1.2.7
worker-1   Ready    <none>   3m3s   v1.15.2   10.240.0.21   <none>        Ubuntu 18.04.2 LTS   4.15.0-1037-gcp   containerd://1.2.7
worker-2   Ready    <none>   3m3s   v1.15.2   10.240.0.22   <none>        Ubuntu 18.04.2 LTS   4.15.0-1037-gcp   containerd://1.2.7

Configuring kubectl for Remote Access

In this section, we will generate a kubeconfig file for the kubectl command line utility based on the admin user credentials.

NOTE: Run the commands in this section from the same directory used to generate the admin client certificates.

The Admin Kubernetes Configuration File

Each kubeconfig requires a Kubernetes API Server to connect to. To support high availability the IP address assigned to the external load balancer fronting the Kubernetes API Servers will be used.

WARNING: The following commands will overwrite your current/default kubeconfig (whatever KUBECONFIG environment variable is pointing to, if it is set. If it is not set, then it will overwrite your $HOME/.kube/config file).

  • Generate a kubeconfig file suitable for authenticating as the admin user:
{
  KUBERNETES_PUBLIC_ADDRESS=$(gcloud compute addresses describe kubernetes-the-hard-way \
    --region $(gcloud config get-value compute/region) \
    --format 'value(address)')

  kubectl config set-cluster kubernetes-the-hard-way \
    --certificate-authority=ca.pem \
    --embed-certs=true \
    --server=https://${KUBERNETES_PUBLIC_ADDRESS}:6443

  kubectl config set-credentials admin \
    --client-certificate=admin.pem \
    --client-key=admin-key.pem

  kubectl config set-context kubernetes-the-hard-way \
    --cluster=kubernetes-the-hard-way \
    --user=admin

  kubectl config use-context kubernetes-the-hard-way
}
Verification
  • Check the health of the remote Kubernetes cluster:
$ kubectl get componentstatuses

NAME                 STATUS    MESSAGE             ERROR
scheduler            Healthy   ok                  
controller-manager   Healthy   ok                  
etcd-1               Healthy   {"health":"true"}   
etcd-2               Healthy   {"health":"true"}   
etcd-0               Healthy   {"health":"true"}

Provisioning Pod Network Routes

Pods scheduled to a node receive an IP address from the node's Pod CIDR range. At this point, pods can not communicate with other pods running on different nodes due to missing network routes.

In this section, we will create a route for each worker node that maps the node's Pod CIDR range to the node's internal IP address.

Note: There are other ways to implement the Kubernetes networking model.

The Routing Table

In this section, we will gather the information required to create routes in the kubernetes-the-hard-way VPC network.

  • Print the internal IP address and Pod CIDR range for each worker instance:
for instance in worker-0 worker-1 worker-2; do
  gcloud compute instances describe ${instance} \
    --format 'value[separator=" "](networkInterfaces[0].networkIP,metadata.items[0].value)'
done

10.240.0.20 10.200.0.0/24
10.240.0.21 10.200.1.0/24
10.240.0.22 10.200.2.0/24

Routes

  • List the default routes in the kubernetes-the-hard-way VPC network:
$ gcloud compute routes list --filter "network: kubernetes-the-hard-way"
NAME                            NETWORK                  DEST_RANGE     NEXT_HOP                  PRIORITY
default-route-294de28447c4e405  kubernetes-the-hard-way  0.0.0.0/0      default-internet-gateway  1000
default-route-638561d1ca3f4621  kubernetes-the-hard-way  10.240.0.0/24  kubernetes-the-hard-way   1000
  • Create network routes for each worker instance:
for i in 0 1 2; do
  gcloud compute routes create kubernetes-route-10-200-${i}-0-24 \
    --network kubernetes-the-hard-way \
    --next-hop-address 10.240.0.2${i} \
    --destination-range 10.200.${i}.0/24
done
  • List the routes in the kubernetes-the-hard-way VPC network:
$ gcloud compute routes list --filter "network: kubernetes-the-hard-way"

NAME                            NETWORK                  DEST_RANGE     NEXT_HOP                  PRIORITY
default-route-294de28447c4e405  kubernetes-the-hard-way  0.0.0.0/0      default-internet-gateway  1000
default-route-638561d1ca3f4621  kubernetes-the-hard-way  10.240.0.0/24  kubernetes-the-hard-way   1000
kubernetes-route-10-200-0-0-24  kubernetes-the-hard-way  10.200.0.0/24  10.240.0.20               1000
kubernetes-route-10-200-1-0-24  kubernetes-the-hard-way  10.200.1.0/24  10.240.0.21               1000
kubernetes-route-10-200-2-0-24  kubernetes-the-hard-way  10.200.2.0/24  10.240.0.22               1000

Deploying the DNS Cluster Add-on

In this section, we will deploy the DNS add-on which provides DNS based service discovery, backed by CoreDNS, to applications running inside the Kubernetes cluster.

The DNS Cluster Add-on

  • Deploy the coredns cluster add-on:
$ kubectl apply -f https://storage.googleapis.com/kubernetes-the-hard-way/coredns.yaml

serviceaccount/coredns created
clusterrole.rbac.authorization.k8s.io/system:coredns created
clusterrolebinding.rbac.authorization.k8s.io/system:coredns created
configmap/coredns created
deployment.extensions/coredns created
service/kube-dns created
  • List the pods created by the kube-dns deployment:
$ kubectl -n kube-system get pods -l k8s-app=kube-dns

NAME                       READY   STATUS    RESTARTS   AGE
coredns-7945fb857d-kpd67   1/1     Running   0          40s
coredns-7945fb857d-rpvwl   1/1     Running   0          40s

Verification

  • Create a busybox deployment:
$ kubectl run busybox --image=busybox:1.31.0 --command -- sleep 3600
  • List the pod created by the busybox deployment:
$ kubectl get pods -l run=busybox
NAME                       READY   STATUS    RESTARTS   AGE
busybox-57786959c7-xpfxv   1/1     Running   0          16s
  • Retrieve the full name of the busybox pod:
$ POD_NAME=$(kubectl get pods -l run=busybox -o jsonpath="{.items[0].metadata.name}")
$ echo $POD_NAME
busybox-57786959c7-xpfxv
  • Execute a DNS lookup for the kubernetes service inside the busybox pod:
$ kubectl exec -ti $POD_NAME -- nslookup kubernetes

Server:    10.32.0.10
Address 1: 10.32.0.10 kube-dns.kube-system.svc.cluster.local

Name:      kubernetes
Address 1: 10.32.0.1 kubernetes.default.svc.cluster.local

Smoke testing

In this section, we will complete a series of tasks to ensure your Kubernetes cluster is functioning correctly and passes a build verification test (BVT).

Data Encryption

Goal: Verify the ability to encrypt secret data at rest.

  • Create a generic secret:
$ kubectl create secret generic kubernetes-the-hard-way \
    --from-literal="mykey=mydata"
  • Print a hexdump of the kubernetes-the-hard-way secret stored in etcd:
$ gcloud compute ssh controller-0 \
  --command "sudo ETCDCTL_API=3 etcdctl get \
  --endpoints=https://127.0.0.1:2379 \
  --cacert=/etc/etcd/ca.pem \
  --cert=/etc/etcd/kubernetes.pem \
  --key=/etc/etcd/kubernetes-key.pem\
  /registry/secrets/default/kubernetes-the-hard-way | hexdump -C"

00000000  2f 72 65 67 69 73 74 72  79 2f 73 65 63 72 65 74  |/registry/secret|
00000010  73 2f 64 65 66 61 75 6c  74 2f 6b 75 62 65 72 6e  |s/default/kubern|
00000020  65 74 65 73 2d 74 68 65  2d 68 61 72 64 2d 77 61  |etes-the-hard-wa|
00000030  79 0a 6b 38 73 3a 65 6e  63 3a 61 65 73 63 62 63  |y.k8s:enc:aescbc|
00000040  3a 76 31 3a 6b 65 79 31  3a a5 d7 cd 20 d1 12 a3  |:v1:key1:... ...|
00000050  47 13 fe cb ea b1 9f f2  1f 63 7d 1f c4 03 cb 3f  |G........c}....?|
00000060  27 b4 3e 40 9a 32 0b 91  a5 84 bf ee 1c b5 9e ea  |'.>@.2..........|
00000070  4c a3 fb e1 6d 83 18 1e  50 42 0b 2d cb 90 c8 92  |L...m...PB.-....|
00000080  f5 29 81 2a 01 db 9d 22  1f 67 3b f4 fd a8 76 59  |.).*...".g;...vY|
00000090  e8 1e e0 a5 91 65 c3 5d  17 0a 32 fc 5e 73 4d 35  |.....e.]..2.^sM5|
000000a0  69 a1 78 d9 a9 83 6b 53  c3 5e aa c9 e0 c4 72 6a  |i.x...kS.^....rj|
000000b0  26 56 8b 5e fc 34 6b f0  12 1f 5b 0a 70 aa 07 de  |&V.^.4k...[.p...|
000000c0  0a de 76 4b ed be 09 61  2c 43 5e e3 35 0b 43 60  |..vK...a,C^.5.C`|
000000d0  e3 d5 34 0b 9e 7b 05 67  30 3c 49 a8 33 9c f2 da  |..4..{.g0<I.3...|
000000e0  4f c9 e9 b5 54 31 f8 14  75 0a                    |O...T1..u.|
000000ea

#~OR~

$ gcloud compute ssh controller-0 \
  --command "sudo ETCDCTL_API=3 etcdctl get \
  --endpoints=https://127.0.0.1:2379 \
  --cacert=/etc/etcd/ca.pem \
  --cert=/etc/etcd/kubernetes.pem \
  --key=/etc/etcd/kubernetes-key.pem\
  /registry/secrets/default/kubernetes-the-hard-way -w fields | grep Value"

"Value" : "k8s:enc:aescbc:v1:key1:\xa5..."

The etcd key should be prefixed with k8s:enc:aescbc:v1:key1, which indicates the Advanced Encryption Standard (AES) - CBC (Cipher Blocker Chaining) provider was used to encrypt the data with the key1 encryption key. See: wikipedia:Block cipher mode of operation for details.

Deployments

In this section, we will verify the ability to create and manage Deployments.

  • Create a deployment for an Nginx web server:
$ kubectl run nginx --image=nginx
  • List the pod created by the nginx deployment:
$ kubectl get pods -l run=nginx

NAME                     READY   STATUS    RESTARTS   AGE
nginx-7bb7cd8db5-7nrsw   1/1     Running   0          14s

Port Forwarding

In this section, we will verify the ability to access applications remotely using port forwarding.

  • Retrieve the full name of the nginx pod:
POD_NAME=$(kubectl get pods -l run=nginx -o jsonpath="{.items[0].metadata.name}")
  • Forward port 8080 on your local machine to port 80 of the nginx pod:
$ kubectl port-forward $POD_NAME 8080:80

Forwarding from 127.0.0.1:8080 -> 80
Forwarding from [::1]:8080 -> 80
  • In a new terminal make an HTTP request using the forwarding address:
$ curl --head http://127.0.0.1:8080
HTTP/1.1 200 OK
Server: nginx/1.17.2
Date: Fri, 09 Aug 2019 22:44:03 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 23 Jul 2019 11:45:37 GMT
Connection: keep-alive
ETag: "5d36f361-264"
Accept-Ranges: bytes
  • Switch back to the previous terminal and stop the port forwarding to the nginx pod:
Forwarding from 127.0.0.1:8080 -> 80
Forwarding from [::1]:8080 -> 80
Handling connection for 8080
^C

Logs

In this section, we will verify the ability to retrieve container logs.

  • Print the nginx pod logs:
$ kubectl logs $POD_NAME
127.0.0.1 - - [09/Aug/2019:22:44:03 +0000] "HEAD / HTTP/1.1" 200 0 "-" "curl/7.58.0" "-"

Exec

In this section, we will verify the ability to execute commands in a container.

  • Print the nginx version by executing the nginx -v command in the nginx container:
$ kubectl exec -ti $POD_NAME -- nginx -v
nginx version: nginx/1.17.2

Services

In this section, we will verify the ability to expose applications using a Service.

  • Expose the nginx deployment using a NodePort service:
$ kubectl expose deployment nginx --port 80 --type NodePort

$ kubectl get svc -l run=nginx
NAME    TYPE       CLUSTER-IP    EXTERNAL-IP   PORT(S)        AGE
nginx   NodePort   10.32.0.112   <none>        80:31119/TCP   23s

NOTE: The LoadBalancer service type can not be used because your cluster is not configured with cloud provider integration. Setting up cloud provider integration is out of scope for this article.

  • Retrieve the node port assigned to the nginx service:
NODE_PORT=$(kubectl get svc nginx \
  --output=jsonpath='{range .spec.ports[0]}{.nodePort}')

$ echo $NODE_PORT 
31119
  • Create a firewall rule that allows remote access to the nginx node port:
$ gcloud compute firewall-rules create kubernetes-the-hard-way-allow-nginx-service \
  --allow=tcp:${NODE_PORT} \
  --network kubernetes-the-hard-way

$ gcloud compute firewall-rules list --filter="name ~ allow-nginx"
NAME                                         NETWORK                  DIRECTION  PRIORITY  ALLOW      DENY  DISABLED
kubernetes-the-hard-way-allow-nginx-service  kubernetes-the-hard-way  INGRESS    1000      tcp:31119        False
  • Retrieve the external IP address of a worker instance:
EXTERNAL_IP=$(gcloud compute instances describe worker-0 \
  --format 'value(networkInterfaces[0].accessConfigs[0].natIP)')
  • Make an HTTP request using the external IP address and the nginx node port:
$ curl -I http://${EXTERNAL_IP}:${NODE_PORT}
HTTP/1.1 200 OK
Server: nginx/1.17.2
Date: Fri, 09 Aug 2019 23:15:01 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 23 Jul 2019 11:45:37 GMT
Connection: keep-alive
ETag: "5d36f361-264"
Accept-Ranges: bytes

Untrusted Workloads

This section will verify the ability to run untrusted workloads using gVisor.

  • Create the untrusted pod:
cat << EOF | kubectl apply -f -
apiVersion: v1
kind: Pod
metadata:
  name: untrusted
  annotations:
    io.kubernetes.cri.untrusted-workload: "true"
spec:
  containers:
    - name: webserver
      image: gcr.io/hightowerlabs/helloworld:2.0.0
EOF
Verification
  • Verify the untrusted pod is running under gVisor (runsc) by inspecting the assigned worker node:
$ kubectl get pods -o wide

NAME                       READY   STATUS    RESTARTS   AGE   IP           NODE       NOMINATED NODE   READINESS GATES
busybox-57786959c7-5wlf4   1/1     Running   1          61m   10.200.1.4   worker-1   <none>           <none>
nginx-7bb7cd8db5-7nrsw     1/1     Running   0          35m   10.200.0.3   worker-0   <none>           <none>
untrusted                  1/1     Running   0          67s   10.200.1.5   worker-1   <none>           <none>
  • Get the node name where the untrusted pod is running:
$ INSTANCE_NAME=$(kubectl get pod untrusted --output=jsonpath='{.spec.nodeName}')

$ echo $INSTANCE_NAME 
worker-1
  • SSH into the worker node:
$ gcloud compute ssh ${INSTANCE_NAME}
  • List the containers running under gVisor:
$ sudo runsc --root /run/containerd/runsc/k8s.io list

I0809 23:19:45.762228   18463 x:0] ***************************
I0809 23:19:45.762415   18463 x:0] Args: [runsc --root /run/containerd/runsc/k8s.io list]
I0809 23:19:45.762481   18463 x:0] Git Revision: 50c283b9f56bb7200938d9e207355f05f79f0d17
I0809 23:19:45.762535   18463 x:0] PID: 18463
I0809 23:19:45.762602   18463 x:0] UID: 0, GID: 0
I0809 23:19:45.762652   18463 x:0] Configuration:
I0809 23:19:45.762695   18463 x:0] 		RootDir: /run/containerd/runsc/k8s.io
I0809 23:19:45.762791   18463 x:0] 		Platform: ptrace
I0809 23:19:45.762899   18463 x:0] 		FileAccess: exclusive, overlay: false
I0809 23:19:45.762996   18463 x:0] 		Network: sandbox, logging: false
I0809 23:19:45.763093   18463 x:0] 		Strace: false, max size: 1024, syscalls: []
I0809 23:19:45.763188   18463 x:0] ***************************
ID                                                                 PID         STATUS      BUNDLE                                                                                                                   CREATED                OWNER
db3d2549c91111eb68467e9aba28723743e34965f0cf6a9683206b2c93bba1bd   17834       running     /run/containerd/io.containerd.runtime.v1.linux/k8s.io/db3d2549c91111eb68467e9aba28723743e34965f0cf6a9683206b2c93bba1bd   0001-01-01T00:00:00Z   
f8dcc505e3e0850da6e33d5fd9e35308951afe8a5ab840a31e19ef93f16dbe7f   17901       running     /run/containerd/io.containerd.runtime.v1.linux/k8s.io/f8dcc505e3e0850da6e33d5fd9e35308951afe8a5ab840a31e19ef93f16dbe7f   0001-01-01T00:00:00Z   
I0809 23:19:45.766604   18463 x:0] Exiting with status: 0
  • Get the ID of the untrusted pod:
$ POD_ID=$(sudo crictl -r unix:///var/run/containerd/containerd.sock \
    pods --name untrusted -q)

$ echo $POD_ID 
db3d2549c91111eb68467e9aba28723743e34965f0cf6a9683206b2c93bba1bd
  • Get the ID of the webserver container running in the untrusted pod:
$ CONTAINER_ID=$(sudo crictl -r unix:///var/run/containerd/containerd.sock \
    ps -p ${POD_ID} -q)

$ echo $CONTAINER_ID 
f8dcc505e3e0850da6e33d5fd9e35308951afe8a5ab840a31e19ef93f16dbe7f
  • Use the gVisor runsc command to display the processes running inside the webserver container:
$ sudo runsc --root /run/containerd/runsc/k8s.io ps ${CONTAINER_ID}

I0809 23:22:26.200992   18720 x:0] ***************************
I0809 23:22:26.201201   18720 x:0] Args: [runsc --root /run/containerd/runsc/k8s.io ps f8dcc505e3e0850da6e33d5fd9e35308951afe8a5ab840a31e19ef93f16dbe7f]
I0809 23:22:26.201275   18720 x:0] Git Revision: 50c283b9f56bb7200938d9e207355f05f79f0d17
I0809 23:22:26.201331   18720 x:0] PID: 18720
I0809 23:22:26.201388   18720 x:0] UID: 0, GID: 0
I0809 23:22:26.201449   18720 x:0] Configuration:
I0809 23:22:26.201494   18720 x:0] 		RootDir: /run/containerd/runsc/k8s.io
I0809 23:22:26.201590   18720 x:0] 		Platform: ptrace
I0809 23:22:26.201792   18720 x:0] 		FileAccess: exclusive, overlay: false
I0809 23:22:26.201900   18720 x:0] 		Network: sandbox, logging: false
I0809 23:22:26.201999   18720 x:0] 		Strace: false, max size: 1024, syscalls: []
I0809 23:22:26.202095   18720 x:0] ***************************
UID       PID       PPID      C         STIME     TIME      CMD
0         1         0         0         23:16     0s        app
I0809 23:22:26.203699   18720 x:0] Exiting with status: 0

Cleanup

In this section, we will delete everything we created in GCP in this article.

Compute Instances

  • Delete the controller and worker compute instances:
gcloud -q compute instances delete \
  controller-0 controller-1 controller-2 \
  worker-0 worker-1 worker-2

Networking

  • Delete the external load balancer network resources:
{
  gcloud -q compute forwarding-rules delete kubernetes-forwarding-rule \
    --region $(gcloud config get-value compute/region)

  gcloud -q compute target-pools delete kubernetes-target-pool

  gcloud -q compute http-health-checks delete kubernetes

  gcloud -q compute addresses delete kubernetes-the-hard-way
}
  • Delete the kubernetes-the-hard-way firewall rules:
gcloud -q compute firewall-rules delete \
  kubernetes-the-hard-way-allow-nginx-service \
  kubernetes-the-hard-way-allow-internal \
  kubernetes-the-hard-way-allow-external \
  kubernetes-the-hard-way-allow-health-check
  • Delete the kubernetes-the-hard-way network VPC:
{
  gcloud -q compute routes delete \
    kubernetes-route-10-200-0-0-24 \
    kubernetes-route-10-200-1-0-24 \
    kubernetes-route-10-200-2-0-24

  gcloud -q compute networks subnets delete kubernetes

  gcloud -q compute networks delete kubernetes-the-hard-way
}

See also

External links

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