question Re: What is "namenode_backup_dir" in Advanced hadoop-env on Ambari? in Support Questions

What is "namenode_backup_dir" in Advanced hadoop-env on Ambari?

toide — Mon, 03 Sep 2018 13:46:16 GMT

What is "namenode_backup_dir" in Advanced hadoop-env on Ambari?

When is this property used?

Re: What is "namenode_backup_dir" in Advanced hadoop-env on Ambari?

jsensharma — Mon, 03 Sep 2018 13:52:48 GMT

Based on the "src/main/resources/stacks/HDP/3.0/services/HDFS/configuration/hadoop-env.xml"

  <property>
    <name>namenode_backup_dir</name>
    <display-name>NameNode Backup directory</display-name>
    <description>Local directory for storing backup copy of NameNode images during upgrade</description>
    <value>/tmp/upgrades</value>
    <on-ambari-upgrade add="false"/>
  </property>

Re: What is "namenode_backup_dir" in Advanced hadoop-env on Ambari?

jsensharma — Mon, 03 Sep 2018 14:06:24 GMT

@Takefumi Oide

In order to get more details about why this property was added and why is it needed inside the "namenode_upgrade.py" script, you can refer to the following JIRA:

During HDP upgrade, Ambari does not allow redirecting the /tmp/upgrade directory elsewhere: https://issues.apache.org/jira/browse/AMBARI-18642

Code Changes: https://github.com/apache/ambari/commit/4b980f36a7de3f19e9bf8d5b8ae4f593931ec1f0

# grep 'namenode_backup_dir' /var/lib/ambari-server/resources/common-services/HDFS/2.1.0.2.0/package/scripts/namenode_upgrade.py
  backup_destination_root_dir = "{0}/{1}".format(params.namenode_backup_dir, params.stack_version_unformatted)<br>

Re: What is "namenode_backup_dir" in Advanced hadoop-env on Ambari?

toide — Mon, 03 Sep 2018 14:16:14 GMT

Thank you very much!