https://community.cloudera.com/t5/Support-Questions/Hbase-Master-Failover/m-p/118769#M81552 <P>Thanks Josh for explaining! A follow question would be what does Master "fail" mean? Sometimes we notice our app talking HBase does not respond. And, then we notice that the Hbase master it was talking to had a resource alert on Ambari UI. And, we do not know if the failover was even initiated(only when one master crashes? What about if it is just slow?). When does failover get initiated? Can you point to some article which talks about it? I can't seem to find one easily online. </P><P>We also tried to do this:</P><P>1. talk to the active master ; Application write<A href="https://community.cloudera.com/legacyfs/online/attachments/12830-hbase-hbase-master-regionserver02stormca-internall.zip">hbase-hbase-master-regionserver02stormca-internall.zip</A>s to the active master some data. Confirmed that the data was there in the active master by scanning the table on hbase shell. </P><P>2. Then failed over (to simulate failover) artificially. Then we did the same as above. List shows the table. But, scan on the table fails. (no response). </P><P>Attached the log with relevant errors. </P> Thu, 23 Feb 2017 04:26:39 GMT manoj_ramakrish 2017-02-23T04:26:39Z