You can roll back an upgrade from HDP 2.6.5.x to CDP Private Cloud Base 7.1.6. The rollback restores your HDP cluster to the state it was in before the upgrade, including Kerberos and TLS/SSL configurations.
Before you start rolling back the CDP Private Cloud Base 7 to HDP 2, review the following information.
- Any data created after the upgrade is lost. In a typical upgrade, you first upgrade Ambari from version 2.6.5 to version 7.1.6, and then you use the upgraded version of Ambari 7.1.6 to upgrade HDP 2 to CDP Private Cloud Base 7. (See Upgrading a Cluster) If you want to roll back this upgrade, follow these steps to roll back your cluster to its state prior to the upgrade.
- Follow all of the steps in the order presented in this topic. Cloudera recommends that you read through the backup and rollback steps before starting the backup process. You may want to create a detailed plan to help you anticipate potential problems.
- You can roll back to HDP 2 after upgrading to CDP Private Cloud Base 7 only if the HDFS upgrade has not been finalized. The rollback restores your HDP cluster to the state it was in before the upgrade, including Kerberos and TLS/SSL configurations.
- These rollback steps depend on complete backups taken before upgrading Ambari and HDP. See Back Up Ambari and Backing up HDP cluster. For steps where you need to restore the contents of a directory, clear the contents of the directory before copying the backed-up files to the directory. If you fail to do this, artifacts from the original upgrade can cause problems if you attempt the upgrade again after the rollback.
- HDFS – If you have finalized the HDFS upgrade, you cannot roll back your cluster.
- Configuration changes, including the addition of new services or roles after the upgrade are not retained after rolling back Ambari. Cloudera recommends that you not make configuration changes or add new services and roles until you have finalized the HDFS upgrade and no longer require the option to roll back your upgrade.
- HBase – If your cluster is configured to use HBase replication, data written to HBase after the upgrade might not be replicated to peers when you start your rollback. This topic does not describe how to determine which, if any, peers have the replicated data and how to roll back that data. For more information about HBase replication, see HBase Replication.
- Kafka – Once the Kafka log format and protocol version configurations (the
log.message.format.versionproperties) are set to the new version (or left blank, which means to use the latest version), Kafka rollback is not possible.
For more information on supported components, see unsupported components.