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 2.1. Prepare for the Stack Upgrade

  1. Make sure that you completed the system preparation procedure; most importantly, save the namespace.

  2. Stage the upgrade script:

    1. Create an "Upgrade Folder", for example /work/upgrade_hdp_2, on a host that can communicate with Ambari Server. The Ambari Server host would be a suitable candidate.

    2. Copy the upgrade script to the Upgrade Folder. The script is available here: /var/lib/ambari-server/resources/scripts/UpgradeHelper_HDP2.py on the Ambari Server host.

    3. Make sure that Python is available on the host and that the version is 2.6 or higher:

      python --version
      [Note]Note

      For RHEL/Centos/Oracle Linux 5, you must use Python 2.6.

  3. Start Ambari Server only. On the Ambari Server host:

    ambari-server start

  4. Back up current configuration settings and the component host mappings from MapReduce:

    1. Go to the Upgrade Folder.

    2. Execute the backup-configs action:

      python UpgradeHelper_HDP2.py --hostname {HOSTNAME} --user {USERNAME} --password {PASSWORD} --clustername {CLUSTERNAME} backup-configs

      Where

      • {HOSTNAME} is the name of the Ambari Server host

      • {USERNAME} is the admin user for Ambari Server

      • {PASSWORD} is the password for the admin user

      • {CLUSTERNAME} is the name of the cluster

      This step produces a set of files named TYPE_TAG, where TYPE is the configuration type and TAG is the tag. These files contain copies of the various configuration settings for the current (pre-upgrade) cluster. You can use these files as a reference later.

    3. Execute the save-mr-mapping action:

      python UpgradeHelper_HDP2.py --hostname {HOSTNAME} --user {USERNAME} --password {PASSWORD} --clustername {CLUSTERNAME} save-mr-mapping

      This step produces a file named mr_mapping that stores the host level mapping of MapReduce components such as MapReduce JobTracker/TaskTracker/Client.

  5.  Delete all the MapReduce server components installed on the cluster.

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

    2. Execute the delete-mr action.

      python UpgradeHelper_HDP2.py --hostname {HOSTNAME} --user {USERNAME} --password {PASSWORD} --clustername {CLUSTERNAME} delete-mr

      Optionally, execute the delete script with the -n option to view, verify, and validate API calls, if necessary.

      [Note]Note

      Running the delete script with the -n option exposes API calls but does not remove installed components. Use the -n option for validation purposes only.

    3. The script asks you to confirm that you have executed the save-mr-mapping action and that you have a file named mr_mapping in the Upgrade Folder.

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