Kubernetes/AWS

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This article will cover topics related to Kubernetes running on AWS, whether running on EKS or stand-alone EC2 instances, etc.

Enable ELB Access Logs via Kubernetes Service

Setup details
  • Kubernetes v1.17.3
  • kubectl v1.17.3
  • 1 x EC2 instance (Ubuntu 16.04) => k8s master+worker node
Initial steps
  • First, setup some environment variables:
$ MY_ELB_LOGS_BUCKET=my-elb-logs
$ ELB_ACCOUNT_ID=797873946194  # <- us-west-2

You can find the appropriate ${ELB_ACCOUNT_ID} here.

  • Create an S3 bucket in which to host your ELB logs:
$ aws s3 mb s3://${MY_ELB_LOGS_BUCKET}
  • Make sure this S3 bucket as the following bucket policy (set under the permissions):
$ cat <<EOF >policy.json
{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Principal": {
                "AWS": "arn:aws:iam::${ELB_ACCOUNT_ID}:root"
            },
            "Action": "s3:PutObject",
            "Resource": "arn:aws:s3:::${MY_ELB_LOGS_BUCKET}/*"
        }
    ]
}
EOF

$ aws s3api put-bucket-policy --bucket ${MY_ELB_LOGS_BUCKET} --policy file://policy.json
Kubernetes setup
  • Create test Nginx Deployment:
$ cat <<EOF | kubectl create -f -
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.17.9
        ports:
        - containerPort: 80
EOF
  • Create a Service to put in front of above Deployment:
$ cat <<EOF | kubectl create -f -
apiVersion: v1
kind: Service
metadata:
  name: frontdoor-service
  annotations:
    service.beta.kubernetes.io/aws-load-balancer-access-log-enabled: "true"
    # The interval for publishing the access logs (can be 5 or 60 minutes).
    service.beta.kubernetes.io/aws-load-balancer-access-log-emit-interval: "5"
    service.beta.kubernetes.io/aws-load-balancer-access-log-s3-bucket-name: "${MY_ELB_LOGS_BUCKET}"
    service.beta.kubernetes.io/aws-load-balancer-access-log-s3-bucket-prefix: "logs/frontdoor"
  labels:
    app: frontdoor
spec:
  type: LoadBalancer
  ports:
  - name: frontdoorport
    port: 30010
    targetPort: 30010
  selector:
    app: nginx
EOF
  • Get information on Service created:
$ kubectl get svc frontdoor-service
NAME                TYPE           CLUSTER-IP     EXTERNAL-IP                                                              PORT(S)           AGE
frontdoor-service   LoadBalancer   10.43.184.39   a371dfd887b56468fa65e126e0d03500-527425434.us-west-2.elb.amazonaws.com   30010:30526/TCP   62m

$ kubectl describe svc frontdoor-service
Name:                     frontdoor-service
Namespace:                default
Labels:                   app=frontdoor
Annotations:              service.beta.kubernetes.io/aws-load-balancer-access-log-emit-interval: 5
                          service.beta.kubernetes.io/aws-load-balancer-access-log-enabled: true
                          service.beta.kubernetes.io/aws-load-balancer-access-log-s3-bucket-name: my-elb-logs
                          service.beta.kubernetes.io/aws-load-balancer-access-log-s3-bucket-prefix: logs/frontdoor
...
AWS details
  • Describe AWS Load Balancer (ELB) Kubernetes automatically created for us:
$ aws elb describe-load-balancer-attributes \
  --profile default \
  --region us-west-2 \
  --load-balancer-name a371dfd887b56468fa65e126e0d03500
{
    "LoadBalancerAttributes": {
        "ConnectionDraining": {
            "Enabled": false,
            "Timeout": 300
        },
        "CrossZoneLoadBalancing": {
            "Enabled": false
        },
        "ConnectionSettings": {
            "IdleTimeout": 60
        },
        "AccessLog": {
            "S3BucketPrefix": "logs/frontdoor",
            "EmitInterval": 5,
            "Enabled": true,
            "S3BucketName": "my-elb-logs"
        }
    }
}
  • Interact with that ELB DNS name so we can generate some traffic for our access logs:
$ ab -c100 -n20000 http://a371dfd887b56468fa65e126e0d03500-527425434.us-west-2.elb.amazonaws.com:30010/

$ for i in $(seq 1 100); do curl -sI http://a371dfd887b56468fa65e126e0d03500-527425434.us-west-2.elb.amazonaws.com:30010/ | grep ^HTTP; done
  • Check that the S3 bucket has ELB access logs:
$ aws s3 ls \
  --profile default \
  --recursive \
  s3://${MY_ELB_LOGS_BUCKET}/logs/frontdoor/
2020-03-04 16:05:12         86 logs/frontdoor/AWSLogs/<redacted>/ELBAccessLogTestFile
2020-03-04 16:25:16        156 logs/frontdoor/AWSLogs/<redacted>/elasticloadbalancing/us-west-2/2020/03/05/<redacted>_elasticloadbalancing_us-west-2_a371dfd887b56468fa65e126e0d03500_20200305T0025Z_54.39.161.151_4jmuxnr9.log
2020-03-04 16:25:31      15434 logs/frontdoor/AWSLogs/<redacted>/elasticloadbalancing/us-west-2/2020/03/05/<redacted>_elasticloadbalancing_us-west-2_a371dfd887b56468fa65e126e0d03500_20200305T0025Z_52.216.39.65_2tv1rd8u.log
  • View the contents of one of those access logs:
$ aws --profile default s3 cp \
  s3://${MY_ELB_LOGS_BUCKET}/logs/frontdoor/AWSLogs/<redacted>/elasticloadbalancing/us-west-2/2020/03/05/<redacted>_elasticloadbalancing_us-west-2_a173dfd887b56468fa65e126e0d03500_20200305T0025Z_52.216.39.65_2tv1rd8u.log - | head -3
2020-03-05T00:22:25.152094Z a371dfd887b56468fa65e126e0d03500 70.104.137.198:35200 10.10.0.167:30526 0.000432 0.000006 0.000015 - - 141 238 "- - - " "-" - -
2020-03-05T00:22:25.243193Z a371dfd887b56468fa65e126e0d03500 70.104.137.198:22800 10.10.0.167:30526 0.000518 0.000007 0.000016 - - 141 238 "- - - " "-" - -
2020-03-05T00:22:25.282568Z a371dfd887b56468fa65e126e0d03500 70.104.137.198:22801 10.10.0.167:30526 0.000422 0.000005 0.000014 - - 141 238 "- - - " "-" - -

Related links

Enable TLS Termination via Kubernetes Service

  • Variables:
$ AWS_PROFILE=default
$ AWS_REGION=us-west-2
$ AWS_ACM_ARN=arn:aws:acm:us-west-2:000000000000:certificate/aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee
$ K8S_CLUSTER_ID=c-abc1d

Note: If your k8s cluster was created by Rancher, the ${K8S_CLUSTER_ID} will look something like "c-abc1d" and you can find this in the Rancher UI.

  • First, tag all AWS VPC Subnets used by your Kubernetes cluster with the following tags:
KubernetesCluster: ${K8S_CLUSTER_ID}
kubernetes.io/role/elb: 1
kubernetes.io/cluster/${K8S_CLUSTER_ID}: owned # <- only needed if cluster was created by Rancher
  • Describe the subnet to validate correct tagging:
$ aws --profile ${AWS_PROFILE} \
      --region ${AWS_REGION} \
      ec2 describe-subnets \
      --subnet-ids subnet-00000000000000000
{
    "Subnets": [
        {
            "Tags": [
                {
                    "Value": "1", 
                    "Key": "kubernetes.io/role/elb"
                },
                {
                    "Value": "c-abc1d", 
                    "Key": "KubernetesCluster"
                },
                {
                    "Value": "owned", 
                    "Key": "kubernetes.io/cluster/c-abc1d"
                }
            ], 
...
        }
    ]
}
  • Create Kubernetes Service and associated Deployment (using sample Nginx container):
$ cat <<EOF | kubectl create -f -
apiVersion: v1
kind: Service
metadata:
  name: nginx-tls-term
  annotations:
    service.beta.kubernetes.io/aws-load-balancer-ssl-cert: "${AWS_ACM_ARN}"
    service.beta.kubernetes.io/aws-load-balancer-ssl-ports: "https"
    service.beta.kubernetes.io/aws-load-balancer-backend-protocol: "http"
    external-dns.alpha.kubernetes.io/hostname: "nginx.example.com"
spec:
  type: LoadBalancer
  ports:
  - name: https
    port: 443
    targetPort: 80
  selector:
    app: nginx
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-tls-term
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx
        ports:
        - containerPort: 80
EOF
  • Describe Kubernetes Service (i.e., the one created above):
$ kubectl get services
NAME            TYPE          CLUSTER-IP     EXTERNAL-IP                                                              PORT(S)        AGE
nginx-tls-term  LoadBalancer  10.43.236.159  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa-0000000000.us-west-2.elb.amazonaws.com  443:30253/TCP  16h

$ kubectl describe service nginx-tls-term
Name:                     nginx-tls-term
Namespace:                default
Labels:                   <none>
Annotations:              external-dns.alpha.kubernetes.io/hostname: nginx.example.com
                          field.cattle.io/publicEndpoints:
                            [{"addresses":["aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa-0000000000.us-west-2.elb.amazonaws.com"],"port":443,"protocol":"TCP","serviceName":"defau...
                          kubectl.kubernetes.io/last-applied-configuration:
                            {"apiVersion":"v1","kind":"Service","metadata":{"annotations":{"external-dns.alpha.kubernetes.io/hostname":"nginx.example.com","service....
                          service.beta.kubernetes.io/aws-load-balancer-backend-protocol: http
                          service.beta.kubernetes.io/aws-load-balancer-ssl-cert: arn:aws:acm:us-west-2:000000000000:certificate/aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee
                          service.beta.kubernetes.io/aws-load-balancer-ssl-ports: https
...
  • Get headers from nginx.example.com:
$ curl -Iv https://nginx.example.com
...
Server certificate:
*  subject: CN=*.example.com
*  start date: Mar 19 00:00:00 2020 GMT
*  expire date: Apr 19 12:00:00 2021 GMT
*  subjectAltName: host "nginx.example.com" matched cert's "*.example.com"
*  issuer: C=US; O=Amazon; OU=Server CA 1B; CN=Amazon
*  SSL certificate verify ok.
HTTP/1.1 200 OK
Accept-Ranges: bytes
Content-Length: 612
Content-Type: text/html
Date: Fri, 20 Mar 2020 17:07:57 GMT
ETag: "5e5e6a8f-264"
Last-Modified: Tue, 03 Mar 2020 14:32:47 GMT
Server: nginx/1.17.9
Connection: keep-alive
  • If using AWS Route53 for your domain name (FQDN => nginx.example.com):
$ aws --profile ${AWS_PROFILE} \
      --region ${AWS_REGION} \
      route53 test-dns-answer \
      --hosted-zone-id ZAAAAAAAAAAAA \
      --record-name nginx.example.com \
      --record-type A
{
    "Protocol": "UDP", 
    "RecordType": "A", 
    "RecordName": "nginx.example.com", 
    "Nameserver": "ns-167.awsdns-20.com", 
    "RecordData": [
        "35.164.250.42",
        "52.41.247.10"
    ], 
    "ResponseCode": "NOERROR"
}
  • If you used AWS's ACM service to create your TLS certification (wildcard in my case):
$ aws --profile ${AWS_PROFILE} \
      acm describe-certificate \
      --certificate-arn ${AWS_ACM_ARN}
{
    "Certificate": {
...
        "DomainValidationOptions": [
            {
                "ValidationStatus": "SUCCESS", 
                "ResourceRecord": {
                    "Type": "CNAME",
                    "Name": "_00000000000000000000000000000000.example.com.",
                    "Value": "_00000000000000000000000000000000.aaaaaaaaaa.acm-validations.aws."
                }, 
                "ValidationDomain": "*.example.com", 
                "ValidationMethod": "DNS", 
                "DomainName": "*.example.com"
            }
        ], 
        "Subject": "CN=*.example.com"
    }
}

External links

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