Upgrading to CDH Maintenance Releases
Use the instructions in this section to upgrade to a CDH maintenance release, that is from CDH a.b.x to CDH a.b.y. For example, CDH 4.7.0 to CDH 4.7.1 or CDH 5.1.0 to 5.1.4.
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.
Before You Begin
- Read the CDH 5 Release Notes.
- Read the Cloudera Manager 5 Release Notes.
- 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
- 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.
- 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.
- 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.