Upgrading to CDH 5
The instructions in this topic describe how to upgrade from a CDH 4 release to a CDH 5 release in a Cloudera Manager deployment. You can upgrade to CDH 5 within the Cloudera Manager Admin Console using parcels or packages and an upgrade wizard. Using parcels vastly simplifies the upgrade process and enables Cloudera Manager to automate the deployment and rollback of CDH minor versions. Electing to upgrade using packages means that all future upgrades and rollbacks will need to be done manually.
- You cannot perform a rolling upgrade from CDH 4 to CDH 5. There are incompatibilities between the major versions, so a rolling restart is not possible. Rolling upgrade is also not supported from CDH 5 Beta 2 to CDH 5.
- Impala - When you upgrade to CDH 5, Impala will be upgraded to 1.3.0.
- If you have just upgraded to Cloudera Manager 5, you must hard restart the Cloudera Manager Agents as described in the Hard Restart Cloudera Manager Agents task in Upgrading Cloudera Manager 4 to Cloudera Manager 5 in Cloudera Manager Administration Guide.
Before You Begin
- Read the Cloudera Manager 5 Release Notes.
- Make sure there are no Oozie workflows in RUNNING or SUSPENDED status; otherwise the Oozie database upgrade will fail and you will have to reinstall CDH 4 to complete or kill those running workflows.
- Run the Host Inspector and fix every issue.
- If using security, run the Security Inspector.
- Run hdfs fsck / and 'hdfs dfsamin -report and fix any issues.
- If using HBase, run hbase hbck to make sure there are no inconsistencies.
- Plan downtime. If you are upgrading a cluster that is part of a production system, be sure to plan ahead. As with any operational work, be sure to reserve a maintenance window with enough extra time allotted in case of complications. The Hadoop upgrade process is well understood, but it is best to be cautious. For production clusters, Cloudera recommends allocating up to a full day maintenance window to perform the upgrade, depending on the number of hosts, the amount of experience you have with Hadoop and Linux, and the particular hardware you are using.
- To avoid generating many alerts during the upgrade process, you can enable maintenance mode on your cluster before you start the upgrade. Be sure to exit maintenance mode when you have finished the upgrade, in order to re-enable Cloudera Manager alerts.