6.1. Setting Maintenance Mode for Services, Components, and Hosts

For example, examine using Maintenance Mode in a 3-node, Ambari-managed cluster installed using default options. This cluster has one data node, on host c6403. This example describes how to explicitly turn on Maintenance Mode for the HDFS service, alternative procedures for explicitly turning on Maintenance Mode for a host, and the implicit effects of turning on Maintenance Mode for a service, a component and a host.

How to Turn On Maintenance Mode for a Service

  1. Using Services, select HDFS.

  2. Select Service Actions, then choose Turn On Maintenance Mode.

  3. Choose OK to confirm.

    Notice, on Services Summary that Maintenance Mode turns on for the NameNode and SNameNode components.

How to Turn On Maintenance Mode for a Host

  1. Using Hosts, select c6401.ambari.apache.org.

  2. Select Host Actions, then choose Turn On Maintenance Mode.

  3. Choose OK to confirm.

    Notice on Components, that Maintenance Mode turns on for all components.

How to Turn On Maintenance Mode for a Host (alternative using filtering for hosts)

  1. Using Hosts, select c6403.ambari.apache.org.

  2. In Actions -> Selected Hosts -> Hosts choose Turn On Maintenance Mode.

  3. Choose OK to confirm.

    Notice that Maintenance Mode turns on for host c6403.ambari.apache.org.

Your list of Hosts now shows Maintenance Mode On for hosts c6401 and c6403.

  • Hover your cursor over each Maintenance Mode icon appearing in the Hosts list.

    • Notice that hosts c6401 and c6403 have Maintenance Mode On.

    • Notice that on host c6401; Ganglia Monitor, HbaseMaster, HDFS client, NameNode, and Zookeeper Server have Maintenance Mode turned On.

    • Notice on host c6402, that HDFS client and Secondary NameNode have Maintenance Mode On.

    • Notice on host c6403, that 15 components have Maintenance Mode On.

  • The following behavior also results:

    • Alerts are suppressed for the DataNode.

    • DataNode is skipped from HDFS Start/Stop/Restart All, Rolling Restart.

    • DataNode is skipped from all Bulk Operations except Turn Maintenance Mode ON/OFF.

    • DataNode is skipped from Start All and / Stop All components.

    • DataNode is skipped from a host-level restart/restart all/stop all/start.


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