Flink 1.7.2: Task Manager not able to connect to Job Manager

[Kumar Bolar, Harshith]

Hi all,

I'm trying to upgrade our Flink cluster from 1.4.2 to 1.7.2

When I bring up the cluster, the task managers refuse to connect to the job 
managers with the following error.

        2019-03-14 10:34:41,551 WARN  akka.remote.ReliableDeliverySupervisor
        - Association with remote system [akka.tcp://flink@cluster:22671] has 
failed, address is now gated for [50] ms. Reason: [Association failed with 
[akka.tcp://flink@cluster:22671]] Caused by: [cluster: Name or service not 
known]

Now, this works correctly if I add the following line into the /etc/hosts file.

        x.x.x.x job-manager-address.com cluster

Why is Flink 1.7.2 connecting to JM using cluster in the address? Flink 1.4.2 
used to have the job manager's address instead of the word cluster.

Thanks,
Harshith