title: Kubernetes: Have no access from EKS pod to RDS Postgres
body: <p>I'm trying to setup kubernetes on AWS. For this I created an EKS cluster with 3 nodes (t2.small) according to official AWS tutorial. Then I want to run a pod with some app which communicates with Postgres (RDS in different VPC). </p>
  
  <p>But unfortunately the app doesn't connect to the database.</p>
  
  <p>What I have:</p>
  
  <ol>
  <li>EKS cluster with its own VPC (CIDR: 192.168.0.0/16)</li>
  <li>RDS (Postgres) with its own VPC (CIDR: 172.30.0.0/16)</li>
  <li>Peering connection initiated from the RDS VPC to the EKS VPC</li>
  <li>Route table for 3 public subnets of EKS cluster is updated: route with destination 172.30.0.0/16 and target — peer connection from the step #3 is added.</li>
  <li>Route table for the RDS is updated: route with destination 192.168.0.0/16 and target — peer connection from the step #3 is added.</li>
  <li>The RDS security group is updated, new inbound rule is added: all traffic from 192.168.0.0/16 is allowed</li>
  </ol>
  
  <p>After all these steps I execute kubectl command:</p>
  
  <pre><code>kubectl exec -it my-pod-app-6vkgm nslookup rds-vpc.unique_id.us-east-1.rds.amazonaws.com
  nslookup: can't resolve '(null)': Name does not resolve
  
  Name:      rds-vpc.unique_id.us-east-1.rds.amazonaws.com
  Address 1: 52.0.109.113 ec2-52-0-109-113.compute-1.amazonaws.com
  </code></pre>
  
  <p>Then I connect to one of the 3 nodes and execute a command:</p>
  
  <pre><code>getent hosts rds-vpc.unique_id.us-east-1.rds.amazonaws.com
  52.0.109.113    ec2-52-0-109-113.compute-1.amazonaws.com rds-vpc.unique_id.us-east-1.rds.amazonaws.com
  </code></pre>
  
  <p>What I missed in EKS setup in order to have access from pods to RDS?</p>
  
  <p><strong>UPDATE:</strong></p>
  
  <p>I tried to fix the problem by <code>Service</code>:</p>
  
  <pre><code>apiVersion: v1
  kind: Service
  metadata:
    name: postgres-service
  spec:
    type: ExternalName
    externalName: rds-vpc.unique_id.us-east-1.rds.amazonaws.com
  </code></pre>
  
  <p>So I created this service in EKS, and then tried to refer to <code>postgres-service</code> as DB URL instead of direct RDS host address.</p>
  
  <p>This fix does not work :(</p>