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NameNode HA - HBASE has to be stopped
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Apache Ambari
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Apache HBase
Created 03-09-2017 01:55 AM
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While configuring NameNode HA its recommended to stop HBASE prior, curious to know why HBASE has to stopped for NameNode High Availability.
Created 03-09-2017 06:41 PM
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HBase Distributed modes require an instance of HDFS. HBase depends on HDFS (Namenode, Datanodes) to perform operations like adding a file etc. So, if you a running cluster where HBase is also installed and you are upgrading HDFS to be HA i.e to Namenode-HA you should stop HBase service.
Also, as Artem mentioned above after upgrading the Namenode to HA, change the distributed file system URI in hbase-site.xml to the name specified in the dfs.nameservices property in hdfs-site.xml.
For example, suppose the HDFS HA property dfs.nameservices is set to mycluster in hdfs-site.xml. Specify that same value as below in hbase-site.xml's hbase.rootdir value:
<!-- Configure HBase to use the HA NameNode nameservice --> <property> <name>hbase.rootdir</name> <value>hdfs://mycluster/hbase</value> </property>
Created 03-09-2017 02:23 AM
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Note that you need at least to restart HBase after configuring NN HA to give HBase a chance to pick up on the new configuration, instead of using only one NN. I guess strictly speaking you can keep HBase running, and restart it once NN HA is over, but it's better to stop it to avoid any inconsistencies and other troubles.
Created 03-09-2017 12:43 PM
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When you enable HA, you essentially are changing name of the namenode with nameservers, you have to update hbase.rootdir property to reflect the nameservices ID and hence the stop.
<property> <name>hbase.rootdir</name> <value>hdfs://namenode.example.org:8020/hbase</value> </property>
Created 03-09-2017 06:41 PM
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HBase Distributed modes require an instance of HDFS. HBase depends on HDFS (Namenode, Datanodes) to perform operations like adding a file etc. So, if you a running cluster where HBase is also installed and you are upgrading HDFS to be HA i.e to Namenode-HA you should stop HBase service.
Also, as Artem mentioned above after upgrading the Namenode to HA, change the distributed file system URI in hbase-site.xml to the name specified in the dfs.nameservices property in hdfs-site.xml.
For example, suppose the HDFS HA property dfs.nameservices is set to mycluster in hdfs-site.xml. Specify that same value as below in hbase-site.xml's hbase.rootdir value:
<!-- Configure HBase to use the HA NameNode nameservice --> <property> <name>hbase.rootdir</name> <value>hdfs://mycluster/hbase</value> </property>
Created 03-09-2017 06:59 PM
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thank you, makes sense
Created 03-09-2017 07:06 PM
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Thanks @Viswa. Can you please upvote and accept the answer as well.
Created 03-09-2017 07:11 PM
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Sure will do, can you please also let me know what kind of preliminary checks I can do after configuring NameHA
Created 03-09-2017 07:20 PM
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These checks should suffice the health of HDFS:
Although the document is for manual upgrade, but the health checks should be good enough
Created 03-10-2017 09:30 PM
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@Viswa - Can we close this now?