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 and an upgrade wizard or using packages. Using parcels vastly simplifies the upgrade process and enables Cloudera Manager to automate the deployment and rollback of CDH versions. Electing to upgrade using packages means that future upgrades and rollbacks will need to be done manually.
- If you upgraded to Cloudera Manager 5 from Cloudera Manager 4.7 or earlier, and then upgrade to CDH 5, Impala will be upgraded to Impala 1.2.3.
- If you continue to run CDH 4 and you had Impala 1.1 or lower, you will be required to upgrade to Impala 1.2.x.
Before You Begin
- Before upgrading, be sure to read about the latest Incompatible Changes and Known Issues and Workarounds in the Cloudera Manager Release Notes.
- 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.
Upgrading Using Parcels
You can upgrade from a version of CDH 4 installed with either parcels or packages to CDH 5 using parcels. Upgrading using parcels is the recommended way to perform a CDH upgrade — the upgrade wizard handles most of the details of the parcel and configuration upgrades. For instructions, see Upgrading from CDH 4 to CDH 5 Parcels.
Upgrading Using Packages
You can upgrade from a version of CDH 4 installed with packages to CDH 5 using packages. For instructions, see Upgrading from CDH 4 Packages to CDH 5 Packages.