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).

But unfortunately the app doesn't connect to the database.

What I have:

1. EKS cluster with its own VPC (CIDR: 192.168.0.0/16)
2. RDS (Postgres) with its own VPC (CIDR: 172.30.0.0/16)
3. Peering connection initiated from the RDS VPC to the EKS VPC
4. 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.
5. 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.
6. The RDS security group is updated, new inbound rule is added: all traffic from 192.168.0.0/16 is allowed

After all these steps I execute kubectl command:

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

Then I connect to one of the 3 nodes and execute a command:

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

What I missed in EKS setup in order to have access from pods to RDS?

UPDATE:

I tried to fix the problem by Service:

apiVersion: v1
kind: Service
metadata:
  name: postgres-service
spec:
  type: ExternalName
  externalName: rds-vpc.unique_id.us-east-1.rds.amazonaws.com

So I created this service in EKS, and then tried to refer to postgres-service as DB URL instead of direct RDS host address.

This fix does not work :(