Issues with region servers in Azure HDInsight
This article describes troubleshooting steps and possible resolutions for issues when interacting with Azure HDInsight clusters.
Scenario: Unassigned regions
hbase hbck command, you see an error message similar to:
multiple regions being unassigned or holes in the chain of regions
From the Apache HBase Master UI, you can see the number of regions that are unbalanced across all region servers. Then, you can run
hbase hbck command to see holes in the region chain.
Holes may be the result of offline regions.
Fix the assignments. Follow the steps below to bring the unassigned regions back to normal state:
Sign in to the HDInsight HBase cluster using SSH.
hbase zkclicommand to connect with ZooKeeper shell.
Exit zookeeper shell by using
Open the Apache Ambari UI, and then restart the Active HBase Master service.
hbase hbckcommand again (without any further options). Check the output and ensure that all regions are being assigned.
Scenario: Dead region servers
Region servers fail to start.
Multiple splitting WAL directories.
Get list of current WALs:
hadoop fs -ls -R /hbase/WALs/ > /tmp/wals.out.
wals.outfile. If there are too many splitting directories (starting with *-splitting), the region server is probably failing because of these directories.
Stop HBase from Ambari portal.
hadoop fs -ls -R /hbase/WALs/ > /tmp/wals.outto get fresh list of WALs.
Move the *-splitting directories to a temporary folder,
splitWAL, and delete the *-splitting directories.
hbase zkclicommand to connect with zookeeper shell.
Restart HBase service.
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