Upgrading to CDH 5.1
Use the instructions in this section to upgrade an earlier version of CDH 5 to CDH 5.1.
If you use parcels, have a Cloudera Enterprise license, and have enabled HDFS high availability, you can perform a rolling upgrade that lets you avoid cluster downtime.
To upgrade from CDH 4 to CDH 5, use the instructions under Upgrading CDH 4 to CDH 5.
Before You Begin
- Read the CDH 5 Release Notes.
- Read the Cloudera Manager 5 Release Notes.
- Ensure Java 1.7 is installed across the cluster. For installation instructions and recommendations, see Upgrading to Oracle JDK 1.7 in a Cloudera Manager Deployment, and make sure you have read Known Issues and Workarounds in Cloudera Manager 5 before you proceed with the upgrade.
- Ensure that the Cloudera Manager minor version is equal to or greater than the CDH minor version. For example:
Target CDH Version Minimum Cloudera Manager Version 5.0.5 5.0.x 5.1.4 5.1.x 5.4.1 5.4.x
- 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.
- Whenever upgrading Impala, whether in CDH or a standalone parcel or package, check your SQL against the newest reserved words listed in incompatible changes. If upgrading across multiple versions or in case of any problems, check against the full list of Impala keywords.
- Run the Host Inspector and fix every issue.
- If using security, run the Security Inspector.
- Run hdfs fsck / and hdfs dfsadmin -report and fix every issue.
- Run hbase hbck.
- Review the upgrade procedure and reserve a maintenance window with enough time allotted to perform all steps. 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 lots of alerts during the upgrade process, you can enable maintenance mode on your cluster before you start the upgrade. This will stop email alerts and SNMP traps from being sent, but will not stop checks and configuration validations from being made. Be sure to exit maintenance mode when you have finished the upgrade in order to re-enable Cloudera Manager alerts.