After installing Portal EE 4.2.3 on RHEL 7.4 and testing API's, "NO DATA" is showing in the Analytics Dashboard view.
Error showing in the Jarvis_Verifier log:
... ERROR [pool-7-thread-2] Worker:406 - [Instance: 7ebf39a7-dc8e-42af-9c5d-1f88ea556003][Thread: pool-7-thread-2] Failed to send document back to kafka:org.I0Itec.zkclient.exception.ZkTimeoutException: Unable to connect to zookeeper server 'zookeeper1:2181' with timeout of 8000 ms
The root cause was – The Name Server was not configured on the Portal host, DNS resolution in the docker network was taking too much of time.
Simple ping between the containers was taking ~15-20 secs.
Hence the connectivity between the Jarvis microservices was timing out.
Resolution – we have added entry corresponding to the name server in the /etc/resolv.conf in the node where components are deployed.
This solved the connectivity issues – and hence all services started working as expected.