Upgrading to the Latest Version of CDH4 in a Cloudera Manager Deployment
The following instructions describe how to upgrade to the latest CDH4 release from an earlier CDH4 release in a Cloudera Managed Deployment. If you are upgrading from a CDH3 release, use the instructions under Upgrading CDH3 to CDH4 in a Cloudera Managed Deployment instead.
- Before You Begin
- Upgrading Using Parcels
- Upgrading Using Packages
- Performing a Rolling Upgrade from CDH4.x to CDH4.1.3 or Later
As of Cloudera Manager 4.5, you can upgrade to CDH4.1.3 (or later) within the Cloudera Manager Admin Console, using parcels and an upgrade wizard. This vastly simplifies the upgrade process. In addition, this will enable Cloudera Manager to automate the deployment and rollback of CDH versions. Electing to upgrade using packages means that future upgrades and rollbacks will still need to be done manually.
If you have CDH4.1.x with a beta version of Cloudera Impala installed, and you plan to upgrade to CDH4.2 or later, you must also upgrade Impala from the beta version to version 1.0 or later. With a parcel installation you can download and activate both parcels before you proceed to restart the cluster.
You will need to change the remote parcel repo URL to point to the location of the released product. Instructions are included below.
Before You Begin
- Before upgrading, be sure to read about the latest Incompatible Changes and Known Issues and Workarounds in the CDH4 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 lots of alerts during the upgrade process, you can enable Maintenance Mode on your cluster before you start the upgrade. You can put the entire cluster into Maintenance Mode using the Enter Maintenance Mode command from the Actions menu on the All Services page. Be sure to Exit Maintenance Mode when you have finished the upgrade in order to re-enable Cloudera Manager alerts.
In CDH4.1.x, an HBase table could have an owner that had full administrative permissions on the table. The owner construct was removed as of CDH4.2.0, and the code now relies exclusively on entries in the acl table. Since table owners do not have an entry in this table, their permissions are removed on upgrade from CDH4.1.x to CDH4.2.0 or later. If you are upgrading from CDH4.1.x to CDH4.2 or later, and using HBase, you must add permissions for HBase owner users to the HBase acl table before you perform the upgrade.
See the Known Issue in the CDH4 Release Notes, specifically the item "Must explicitly add permissions for owner users before upgrading from 4.1.x" in the Known Issues in Apache HBase section.
Hive has undergone major version changes from CDH 4.0 to 4.1 and between CDH 4.1 and 4.2. (CDH 4.0 had Hive 0.8.0, CDH 4.1 used Hive 0.9.0, and 4.2 or later has 0.10.0). This requires the user to manually back up and upgrade their Hive metastore database when upgrading between major Hive versions. This step is included in the upgrade procedures referenced below.
In Cloudera Manager, if you are upgrading from a version of CDH prior to CDH4.2, you must follow the steps in the appropriate CDH upgrade procedure below for upgrading the metastore. This step should be done before you start the Hive service. This applies whether you are upgrading to packages or parcels.
Upgrading Using Parcels
If you are running Cloudera Manager 4.5 or later, and want to upgrade to CDH4.1.3 or later, see Upgrading to a Newer CDH 4 Version with Parcels for instructions.
Upgrading Using Packages
If you want to upgrade to a version of CDH4 earlier than 4.1.2, you will still need to follow the package upgrade instructions below (see Upgrading CDH 4 Using Packages).
Performing a Rolling Upgrade from CDH4.x to CDH4.1.3 or Later
The feature described in this section is not available in Cloudera Manager with Cloudera Standard.
If you have been using the Cloudera Enterprise Trial Edition, this feature will no longer be available after your trial license expires.
To obtain a license for Cloudera Enterprise, please contact email@example.com. When you install your Enterprise license, this feature will be enabled.
If you are using Cloudera Enterprise, are performing an upgrade between CDH4 versions, and have enabled HDFS High Availability, you may optionally follow the Rolling Upgrade procedure. Rolling Upgrade is not available with Cloudera Standard.
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