1. I installed kubeadm cluster with firewall enabled in centos 7.
2. I had pod which runs flyway migrations. Mentioned domain name of DB. But pod terminated by throwing UnknownHostException. Unable to connect to external server from pod. When ip address of DB is mentioned works fine.
3. Works fine when domain name or ip address mentioned if firewall is disabled.

How to solve UnknownHostException when domain name is mentioned if firewall is enabled.