Difference between revisions of "Rancher"

Revision as of 19:45, 28 March 2018 (view source) Christoph (Talk | contribs) (→‎Install and configure Network Time Protocol (NTP)) ← Older edit		Revision as of 19:46, 28 March 2018 (view source) Christoph (Talk | contribs) (→‎Install and configure external database) Newer edit →
Line 302:		Line 302:
	* Install MariaDB Server:		* Install MariaDB Server:
	$ sudo yum install -y mariadb-server		$ sudo yum install -y mariadb-server
−	$ sudo systemctl start mariadb	+	$ sudo systemctl start mariadb && sudo systemctl enable mariadb
−	$ sudo systemctl enable mariadb	+
	* Configure MariaDB Server:		* Configure MariaDB Server:

---

Revision as of 19:46, 28 March 2018

Rancher is a container management platform. Rancher natively supports and manages all of your Cattle, Kubernetes, Mesos, and Swarm clusters.

Container management

• App Catalog
• Orchestration: Compose, Kubernetes, Marathon, etc.
• Scheduling: Swarm, Kubernetes, Mesos, etc.
• Monitoring: cAdvisor, Sysdig, Datadog, etc.
• Access Control: LDAP, AD, GitHub, etc.
• Registry: DockerHub, Quay.io, etc.
• Engine: Docker, Rkt, etc.
• Security: Notary, Vault, etc.
• Network: VXLAN, IPSEC, HAProxy, etc.
• Storage: Ceph, Gluster, Swift, etc.
• Distributed DB: Etcd, Consul, MongoDB, etc.

Setup Rancher HA with AWS

For my Rancher HA with AWS setup, I will use the following:

Virtual Private Cloud (VPC)

• Virtual Private Cloud (VPC): rancher-vpc (w/3 subnets)
• VPC CIDR: 172.22.0.0/16
• Rancher management subnet: 172.22.1.0/24 (us-west-2a)

Rancher management server nodes (EC2 instances)

• Rancher management server nodes (EC2 instances running CentOS 7):
  • mgmt-host-1 (172.22.1.210)
  • mgmt-host-2 (172.22.1.211)
  • mgmt-host-3 (172.22.1.212)

Each of the Rancher management server nodes (referred to as "server nodes" from now on) will have Docker 1.10.3 installed and running.

Each of the server nodes will have the following security group inbound rules:

External database (RDS)

The external database (DB) will be running on an AWS Relational Database Service (RDS) and we shall call this RDS: "rancher-ext-db" and it will be listening on port 3306 on 172.22.1.26 and be in VPC "rancher-vpc". The RDS will be running MariaDB 10.0.24.

External load balancer (ELB)

The external load balancer (LB) will be running on an AWS Elastic Load Balancer (ELB) and we shall call this ELB: "rancher-ext-lb". It will be in VPC "rancher-vpc" and it will have the following listeners configured:

• Create ELB policies:

$ AWS_PROFILE=dev
$ LB_NAME=rancher-ext-lb
$ POLICY_NAME=rancher-ext-lb-ProxyProtocol-policy
$ aws --profile ${AWS_PROFILE} elb create-load-balancer-policy \
      --load-balancer-name ${LB_NAME} \
      --policy-name ${POLICY_NAME} \
      --policy-type-name ProxyProtocolPolicyType \
      --policy-attributes AttributeName=ProxyProtocol,AttributeValue=true
$ aws --profile ${AWS_PROFILE} elb set-load-balancer-policies-for-backend-server \
      --load-balancer-name ${LB_NAME} \
      --instance-port 81 \
      --policy-names ${POLICY_NAME}
$ aws --profile ${AWS_PROFILE} elb set-load-balancer-policies-for-backend-server \
      --load-balancer-name ${LB_NAME} \
      --instance-port 444 \
      --policy-names ${POLICY_NAME}

Rancher HA management stack

A fully functioning Rancher HA setup will have the following Docker containers running:

Setup Rancher HA on bare-metal

This section will show you how to setup Rancher in High Availability (HA) mode on bare-metal servers. We will also setup a Kubernetes cluster managed by Rancher.

Since a given version of Rancher requires specific versions of Docker and Kubernetes, we will use the following:

• Hardware: 4 x bare-metal servers (rack-mounted):
  • rancher01.dev # Rancher HA Master #1 + Worker Node #1
  • rancher02.dev # Rancher HA Master #2 + Worker Node #2
  • rancher03.dev # Rancher HA Master #3 + Worker Node #3
  • rancher04.dev # Worker Node #4
• OS and software:
  • CentOS 7.4
  • Rancher 1.6
  • Docker 17.03.x-ce
  • Kubernetes 1.8

Install and configure Docker

Note: Perform all of the actions in this section on all 4 bare-metal servers.

• Install Docker 17.03 (CE):

$ sudo yum update -y
$ curl https://releases.rancher.com/install-docker/17.03.sh | sudo sh
$ sudo systemctl enable docker
$ sudo usermod -aG docker $(whoami)  # logout and then log back in

• Check that Docker has been successfully installed:

$ docker --version
Docker version 17.03.2-ce, build f5ec1e2
$ docker run hello-world
...
This message shows that your installation appears to be working correctly.
... 

• Cleanup unused containers:

$ docker rm $(docker ps -a -q)

• Prevent Docker from being upgraded (i.e., lock it to always use Docker 17.03):

$ sudo yum -y install yum-versionlock
$ sudo yum versionlock add docker-ce docker-ce-selinux
$ yum versionlock list
Loaded plugins: fastestmirror, versionlock
0:docker-ce-17.03.2.ce-1.el7.centos.*
0:docker-ce-selinux-17.03.2.ce-1.el7.centos.*

Note: If you ever need to remove this version lock, you can run `sudo yum versionlock delete docker-ce-*`.

Install and configure Network Time Protocol (NTP)

see Network Time Protocol for details.

Note: Perform all of the actions in this section on all 4 bare-metal servers.

• Install NTP:

$ sudo yum install -y ntp
$ sudo systemctl start ntpd && sudo systemctl enable ntpd

• Configure NTP (note: add the closest NTP pool of servers to your bare-metal server's location) by editing /etc/ntp.conf and add/update the following lines:

$ sudo vi /etc/ntp.conf
restrict default nomodify notrap nopeer noquery kod limited
#...
server 0.north-america.pool.ntp.org iburst
server 1.north-america.pool.ntp.org iburst
server 2.north-america.pool.ntp.org iburst
server 3.north-america.pool.ntp.org iburst

• Restart NTP and check status:

$ sudo systemctl restart ntpd
$ ntpq -p   # list NTP pools stats
$ ntpdc -l  # list NTP clients

Install and configure external database

Note: Perform all of the actions in this section on rancher04.dev (i.e., Worker Node #4) only. I will use MariaDB 5.5.x.

• Install MariaDB Server:

$ sudo yum install -y mariadb-server
$ sudo systemctl start mariadb && sudo systemctl enable mariadb

• Configure MariaDB Server:

$ sudo mysql_secure_installation  # Follow the recommendations

• Edit /etc/my.cnf and add the following under the [mysqld] section:

max_allowed_packet=16M

• Restart MariaDB Server:

$ sudo systemctl restart mariadb

• Log into MariaDB Server and create database and user for Rancher:

$ mysql -u root -p
mysql> CREATE DATABASE IF NOT EXISTS <DB_NAME> COLLATE = 'utf8_general_ci' CHARACTER SET = 'utf8';
mysql> GRANT ALL ON <DB_NAME>.* TO '<DB_USER>'@'%' IDENTIFIED BY '<DB_PASSWD>';
mysql> GRANT ALL ON <DB_NAME>.* TO '<DB_USER>'@'localhost' IDENTIFIED BY '<DB_PASSWD>';

Replace <DB_NAME>, <DB_USER>, and <DB_PASSWD> with values of your choice.

Install and configure Rancher HA Master nodes

Note: Perform all of the actions in this section on all 3 x Rancher HA Master servers (do not perform any of these actions on rancher04.dev).

• Make sure all of your Rancher HA Master servers have the following ports opened between themselves:

9345
8080

• Make sure all of your Rancher HA Master servers can reach port 3306 on the server where MariaDB Server is running (i.e., rancher04.dev).

• Start Rancher on all three Rancher HA Master servers:

$ HOST_IP=10.x.x.x      # <- replace with the host IP address of where these commands will be run from
$ DB_HOST=10.x.x.x      # <- replace with the private IP address of the host where MariaDB is running
$ DB_PORT=3306
$ DB_NAME=<DB_NAME>     # <- replace with actual value
$ DB_USER=<DB_USER>     # <- replace with actual value
$ DB_PASSWD=<DB_PASSWD> # <- replace with actual value

$ docker run -d --restart=unless-stopped -p 8080:8080 -p 9345:9345 rancher/server \
 --db-host ${DB_HOST} --db-port ${DB_PORT} --db-user ${DB_USER} --db-pass ${DB_PASSWD} --db-name ${DB_NAME} \
 --advertise-address ${HOST_IP}

• Check the logs for the container started by the above command:

$ docker logs -f <container_id>

Once you see the following message:

msg="Listening on :8090"

Rancher should be setup (in HA mode). You should now be able to bring up the Rancher UI by using the public IP of any one of your Rancher HA Master nodes in your browser with port 8080 (e.g., http://1.2.3.4:8080</code>).

Setup Nginx reverse proxy to act as a Load Balancer

Since we have 3 x Master Rancher nodes for our High Availability (HA) setup, we want to have some kind of load balancer (LB) to act as a single point of entry to the Rancher UI. We have various options available: 1) Use a hardware LB, use some external software LB, use an external Cloud-based LB (e.g., AWS ELB), or we could setup a simple Nginx reverse proxy residing on one of our bare-metal servers. Since we are already using the non-Master node (i.e., rancher04.dev) as our "external database", we can also use it for our Nginx reverse proxy. Note that this is not something you want to do in production. However, since we are just setting up a Proof-of-Concept (POC) and we are limited to only using these 4 bare-metal servers for our entire setup, using the very light-weight Nginx reverse proxy as our "external load balancer" will do the job just fine.

Note: All of the actions performed in this section will be done on rancher04.dev only.

• Install Nginx:

$ sudo yum install -y epel-release
$ sudo yum install -y nginx

• Make sure /etc/nginx/nginx.conf has the following line under the html{} block of configuration settings:

include /etc/nginx/conf.d/*.conf;

• Create the reverse proxy with:

$ cat << EOF >/etc/nginx/conf.d/rancher.conf
upstream rancher_ui {
    # Replace with actual _private_ IPs of your Rancher Master nodes
    server x.x.x.x:8080;
    server y.y.y.y:8080;
    server z.z.z.z:8080;
}

server {
    listen 80 default_server;
    listen [::]:80;

    server_name _;
    #index index.html index.htm;

    access_log /var/log/nginx/rancher.log;
    error_log /var/log/nginx/rancher.err;

    location / {
        proxy_pass http://rancher_ui;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header X-Forwarded-Port $server_port;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_redirect default;
        proxy_cache off;
    }
}
EOF

• Start and enable Nginx:

$ sudo systemctl start nginx && sudo systemctl enable nginx

If you get an error while trying to start Nginx that looks something like the following:

failed (13: Permission denied) while connecting to upstream

you probably have SELinux set to "enforcing" mode. You can fix this by one of the following methods:

$ sudo setenforce 0  # This changes SELinux to "permissive" mode, but not a good idea for production
#~OR~
$ sudo setsebool -P httpd_can_network_connect 1

Now, put the public IP address of rancher04.dev into your browser and you should see the Rancher UI.

Install and configure Rancher Worker nodes

Note: Perform all of the actions in this section on all 4 x bare-metal servers.

We will now add our Worker Nodes. Since the Master nodes will also be acting as Worker nodes and the 4th node (rancher04.dev) is just a Worker node, we need to do the following on all 4 servers.

Follow the instructions for adding a host in the Rancher UI. After working through the steps in the Rancher UI, it should provide you with a Docker command you should run on a given host, which looks something like the following:

$ HOST_IP=x.x.x.x
$ sudo docker run -e CATTLE_AGENT_IP="${HOST_IP}" \
    --rm --privileged -v /var/run/docker.sock:/var/run/docker.sock \
    -v /var/lib/rancher:/var/lib/rancher rancher/agent:v1.2.10 \
    http://z.z.z.z/v1/scripts/xxxx:yyyy:zzzz

External links

• Official website