UnknownHostException using internal DNS name

I’ve got a Couchbase 6.6 cluster in AWS with multiple data nodes. Each server node in Couchbase is configured with an internal DNS name of i-xxxxxx.dev.company.aws, where i-xxxxxx is the EC2 instance ID.

I’ve configured MSK Connect to use the 4.1.7 of the Couchbase Kafka Connector.

MSK Connect is configured to run in a security group that allows access to the cluster, and access to the internet.

MSK Connect is unable to connect via DNS and has the following errors in the logs:

Connect attempt to i-xxxxxx.dev.company.aws:11210 failed. 
java.net.UnknownHostException: i-xxxxxx.dev.company.aws:11210 failed.
  at java.base/java.net.InetAddress$CachedAddresses.get(InetAddress.java:797)

My connect configuration specifics IP addresses in the value for couchbase.seed.nodes, which indicates it’s able to connect via the IP addresses to get the server information from the cluster, but is unable to connect via the names.

I’m able to both telnet & nslookup the names using an EC2 machine in the same security group.

The i-xxxxxx.dev.company.aws records are configured as A records in Route53 to the internal IP address

Hi @shannon ,

I don’t know anything about configuring DNS in AWS, but I can recommend the SDK Doctor tool for diagnosing Couchbase connection issues. Perhaps it will point you in the right direction?


I wonder if this could be related? AWS managed service unable to resolve DNS via Route53 - Stack Overflow