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NameNode HA - HBASE has to be stopped

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NameNode HA - HBASE has to be stopped

Expert Contributor

While configuring NameNode HA its recommended to stop HBASE prior, curious to know why HBASE has to stopped for NameNode High Availability.

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Accepted Solutions

Re: NameNode HA - HBASE has to be stopped

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>
8 REPLIES 8

Re: NameNode HA - HBASE has to be stopped

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.

Re: NameNode HA - HBASE has to be stopped

Mentor
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>

Re: NameNode HA - HBASE has to be stopped

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>

Re: NameNode HA - HBASE has to be stopped

Expert Contributor

thank you, makes sense

Re: NameNode HA - HBASE has to be stopped

Thanks @Viswa. Can you please upvote and accept the answer as well.

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Re: NameNode HA - HBASE has to be stopped

Expert Contributor

Sure will do, can you please also let me know what kind of preliminary checks I can do after configuring NameHA

Re: NameNode HA - HBASE has to be stopped

These checks should suffice the health of HDFS:

https://docs.hortonworks.com/HDPDocuments/HDP2/HDP-2.5.3/bk_command-line-upgrade/content/verify-hdfs...

Although the document is for manual upgrade, but the health checks should be good enough

Re: NameNode HA - HBASE has to be stopped

@Viswa - Can we close this now?

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