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External DNS

The integration helps configure public DNS servers with information about Kubernetes services to make them discoverable.

Prerequisites​

Providers have to be set up for this pack to get deployed and work seamlessly. For a list of supported providers and the prerequisites to be set up, visit providers section

Versions Supported​

  • 0.13.1
  • 0.12.2

Components​

Integration deploys the following components:

  • External DNS

ExternalDNS for Services on AWS Route53 Example​

Setup prerequisites for AWS Route53​

  • Create the following IAM policy in the AWS account. This is needed for externalDNS to list and create Route53 resources.
{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": ["route53:ChangeResourceRecordSets"],
      "Resource": ["arn:aws:route53:::hostedzone/*"]
    },
    {
      "Effect": "Allow",
      "Action": ["route53:ListHostedZones", "route53:ListResourceRecordSets"],
      "Resource": ["*"]
    }
  ]
}
  • Create an IAM role and associate the policy created above. Make a note of the role ARN which will be used in ExternalDNS deployment later
  • Setup hosted zone in AWS Route53 
    # Create a DNS zone through AWS CLI
    aws route53 create-hosted-zone --name "external-dns-test.my-org.com." --caller-reference "external-dns-test-$(date +%s)"

Deploy ExternalDNS on the cluster​

  • Add ExternalDNS pack to the desired profile and deploy it to the cluster. You may want to configure the following in pack values.yaml

    • Configure AWS provider details (line #86)

      • Credentials, Zone Type
      • AssumeRoleArn with the Role ARN created above

    • Configure txtOwnerId with the ID of the hosted zone created above (line #366)

      aws route53 list-hosted-zones-by-name --output json --dns-name "external-dns-test.my-org.com." | jq -r '.HostedZones[0].Id'

    • Optionally change externalDNS policy and logLevel

Deploy Ingress Controller on the cluster​

  • Deploy one of the Ingress Controller on the cluster

Deploy Applications with Ingress on the cluster​

  • Add Prometheus-Operator addon to the same profile where ExternalDNS is added

    • Change serviceType to ClusterIP (line #408)

    • Enable Ingress for the add-on packs. In this example, let us use Prometheus-Operator integration. Ingress config for Grafana will look like the following:

      #Ingress config
      ingress:
        ## If true, Grafana Ingress will be created
        ##
        enabled: true

        hosts:
          - grafana.external-dns-test.my-org.com

        ## Path for grafana ingress
        path: /

      When Prometheus-Operator gets deployed in the Cluster, Ingress resource for Grafana will also get created and will look like

      apiVersion: extensions/v1beta1
      kind: Ingress
      metadata:
        name: grafana-ingress
        namespace: monitoring
      spec:
        rules:
          - host: grafana.external-dns-test.my-org.com
            http:
              paths:
                - backend:
                    serviceName: grafana
                    servicePort: 80
                  path: /
      status:
        loadBalancer:
          ingress:
            - hostname: a9a2eadb64c8e4c2fb37a1f69afb0a30-330939473.us-west-2.elb.amazonaws.com

Verify ExternalDNS (Ingress example)​

  • If all goes well, after 2 minutes, ExternalDNS would have inserted 2 records on your hosted zone

    aws route53 list-resource-record-sets --output json --hosted-zone-id "/hostedzone/ZEWFWZ4R16P7IB" \
        --query "ResourceRecordSets[?Name == 'grafana.external-dns-test.my-org.com.']|[?Type == 'A']"

  • After which, if you access http://grafana.external-dns-test.my-org.com on your browser, you will be able to view the Grafana login page

Troubleshooting​

  • Make sure Ingress resource gets created for the Applications deployed and a LoadBalancer hostname / IP address is set on the Ingress resource
  • Check the external-dns pod for any issues with ExternalDNS not inserting records. If required, change logLevel to debug to see additional info on the logs

References​