Apache Ambari Upgrade
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Chapter 2. Getting Ready to Upgrade Ambari and HDP

When preparing to upgrade Ambari and the HDP Cluster, we strongly recommend you review this checklist of items to confirm your cluster operation is healthy. Attempting to upgrade a cluster that is operating in an unhealthy state can produce unexpected results.

[Important]Important

If planning to upgrade Ambari and upgrade to a new HDP minor version (for example: moving from HDP 2.2 to HDP 2.3), upgrade Ambari to the latest version before upgrading the cluster.

  • Ensure all services in the cluster are running.

  • Run each Service Check (found under the Service Actions menu) and confirm they execute successfully.

  • Clear all alerts, or understand why they are being generated. Remediate as necessary.

  • Confirm start and stop for all services are executing successfully.

  • Time service start and stops. The time to start and stop services is a big contributor to overall upgrade time so having this information handy is useful.

  • Download the software packages prior to the upgrade. Place them in a local repository and/or consider using a storage proxy since multi-gigabyte downloads will be required on all nodes in the cluster.

  • Ensure point-in-time backups are taken of all databases that support the cluster. This includes (among others) Ambari, Hive Metastore, Ranger and Oozie.

    [Note]Note

    If you are upgrading to Ambari 2.5.x, you must make sure that the Ranger db root password is NOT set to blank before performing any HDP upgrade. Ambari requires that the Ranger db root password has a value. If you upgrade Ambari to 2.2 and upgrade HDP without setting a value for the Ranger db root password, Ranger Admin will fail to start after the upgrade.

    To prepare Ranger for upgrades, set the password for the Ranger DB root user to a non-blank value. Then, set the Ranger db root password field in Ambari Web to match this value. Finally, restart Ranger Admin using Ambari Web.

    For Large Clusters

    In a large cluster, NameNode startup processes can take a long time. NameNode startup time depends not only on host properties, but also on data volume and network parameters. To ensure that the Ambari requests to start the NameNode do not timeout during an upgrade, you should configure the Ambari NameNode restart timeout parameter, upgrade.parameter.nn-restart.timeout in /etc/ambari-server/conf/ambari.properties on the Ambari Server host. You may need to add the restart timeout parameter and value to the Ambari server host, following a default installation. For a large cluster, you should add ten percent to the usual time (in seconds) required to restart your NameNode. Although no standard way to determine an appropriate value exists, you may use the following guidance:

    For example, record the time (seconds) required to restart the active NameNode for your current Ambari server version. If restarting takes 10 minutes, (600 seconds) and your cluster is large, then add

    upgrade.parameter.nn-restart.timeout=660

    to the /etc/ambari-server/conf/ambari.properties file on the Ambari Server host.

    After adding or resetting the Ambari Namenode restart parameter, restart your Ambari server before upgrading it to a newer version.

    ambari-server restart

    For Ambari Upgrades

    • This (Ambari 2.6.x) Upgrade Guide will help you upgrade your existing Ambari server to version 2.6.x. If you are upgrading to another Ambari version, please be sure to use the Ambari Upgrade Guide for that version.

    • Be sure to review the Known Issues and Behavioral Changes for this, Ambari-2.6.x release.

    For HDP Cluster Upgrades

    • Ensure sufficient disk space on /usr/hdp/<version> (roughly 3GB for each additional HDP release).

    • If you plan to add new services available with HDP to your cluster, the new services might include new service accounts. Any operational procedures required to support these new service accounts should be performed prior to the upgrade. The accounts will typically be required on all nodes in the cluster.

    • If your cluster includes Storm, document any running Storm topologies.

More Information

Stack Compatibility Matrix

Using a Local Repository

Ambari 2.6.2 Release Notes

Preparing to Upgrade Ambari