4.3. Add YARN/MR2 and Update Configurations

  1. Start the Ambari Server. On the Server host:

    ambari-server start
  2. Start each Ambari Agent. On all Agent hosts:

    ambari-agent start
  3. After the Server and all Agents are running, log into Ambari Web. Do a hard refresh on your browser to make sure you are displaying the updated GUI. Make sure all hosts are healthy and all services are in a Stopped state.

  4. Add YARN and MapReduce2 services:

    1. If you are not already there, go to the Upgrade Folder.

    2. Execute the add-yarn-mr2 action:

      python UpgradeHelper_HDP2.py --hostname $HOSTNAME --user $USERNAME --password $PASSWORD --clustername $CLUSTERNAME add-yarn-mr2

      If desired, you can use the -n option to see the API calls as they are being made so that you can verify them.

  5. Update the respective configurations:

    1. If you are not already there, go to the Upgrade Folder.

    2. Execute the update-configs action:

      python UpgradeHelper_HDP2.py --hostname $HOSTNAME --user $USERNAME --password $PASSWORD --clustername $CLUSTERNAME update-configs
  6.  Update individual configuration settings as needed. On the Ambari Server, use /var/lib/ambari-server/resources/scripts/configs.sh to inspect and update the configuration properties.

    [Note]Note

    configs.sh creates temporary files. We recommended that you run configs.sh as root or as a user having write permission on the local folder.

    1. Get configuration details:

      configs.sh get $HOSTNAME $CLUSTERNAME $CONFIGURATION-TYPE
      
      For example:
      configs.sh get localhost myclustername global
    2. Evaluate each property value returned and modify as needed:

      configs.sh set $HOSTNAME $CLUSTERNAME $CONFIGURATION-TYPE "property name" "new value"
      
      For example:
      configs.sh set localhost myclustername global yarn_log_dir_prefix "/apps/logs/yarn"
    3. Remove properties that are not needed:

      configs.sh delete $HOSTNAME $CLUSTERNAME $CONFIGURATION-TYPE "property name"
      
      For example:
      configs.sh delete localhost myclustername global dfs.client-write-packet-size 
      Table 3.1. Key Properties to Check
      Configuration Type Property Description
      global yarn_log_dir_prefix The location for the YARN logs
      global yarn_pid_dir_prefix The location for the YARN pid files
      global yarn_user The YARN user
      yarn-site yarn.nodemanager.local-dirs The location for container logs
      yarn-site yarn.nodemanager.log-dirs The directories for localized files
      [Note]Note

      Make any necessary modifications before starting the services.

    4. Install the YARN and MapReduce2 services:

      1. If you are not already there, go to the Upgrade Folder.

      2. Execute the install-yarn-mr2 action:

        python UpgradeHelper_HDP2.py --hostname $HOSTNAME --user $USERNAME --password $PASSWORD --clustername $CLUSTERNAME install-yarn-mr2
        [Note]Note

        This is a two-step process. You can use the Ambari Web GUI to monitor the progress. Both steps must be complete before you continue to the next step.