NoServerForRegionException while running Hadoop Ma

Question

I am executing a simple Hadoop MapReduce program with HBase as an input and output. I am getting the error:

java.lang.RuntimeException: org.apache.hadoop.hbase.client.NoServerForRegionException: Unable to find region for OutPut,,99999999999999 after 10 tries.

Answer 1

Query bin/hbase hbck and find in which machine Region server is running. Make sure that all your Region server is up and running. Use start regionserver for starting Region server

Answer 2

This exception appeared to us when there was difference in hbase version.

Our code was built with and running with 0.94.X version of hbase jars. Whereas the hbase server was running on 0.90.3.

When we changed our pom file with right version (0.90.3) of hbase jars it started working fine.

Answer 3

Deleting (or move to /tmp) the WAL logs helped in our case:

hdfs dfs -mv /apps/hbase/data/MasterProcWALs/state-*.log /tmp

Answer 4

Even if Regionserver at the machine is started it may fail because of time sync.

Make sure you have NTP installed on all Regionserver nodes and HbaseMaster node.

As Hbase works on a key-value pair where it uses the Timestamp as the Index, So it allows a time skew less than 3 seconds.