Before You Begin

• Before upgrading, be sure to read about the latest Incompatible Changes and Known Issues and Workarounds in the CDH 4 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 The Security Inspector.
• 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 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 to re-enable Cloudera Manager alerts.

Download, Distribute, and Activate Parcels

1. In the Cloudera Manager Admin Console, click the Parcels indicator in the top navigation bar ( or ) to go to the Parcels page.
2. In the parcels page, click Download for the version(s) you want to download. If the parcel you want is not shown here — for example, you want to upgrade to version of CDH that is not the most current version — you can make additional parcel repos available through the parcel settings page. If your Cloudera Manager server does not have Internet access, you can obtain the required parcel file(s) and put them into the local repository. See Creating and Using a Remote Parcel Repository for Cloudera Manager for more details.
3. When the download has completed, click Distribute for the version you downloaded.
4. When the parcel has been distributed and unpacked, the button will change to say Activate.
5. Click Activate. You are asked if you want to restart the cluster. Do not restart the cluster at this time.
6. Click Close.

Upgrade the Hive Metastore Database

Required if you are upgrading from an earlier version of CDH 4 to CDH 4.2 or higher.

1. Go to the Hive service.
2. Select Actions > Stop and click Stop to confirm.
3. Select Actions > Upgrade Hive Metastore Database Schema and click Upgrade Hive Metastore Database Schema to confirm.
4. If you have multiple instances of Hive, perform the upgrade on each metastore database.

Upgrade the Oozie ShareLib

1. Go to the Oozie service.
2. Select Actions > Start and click Start to confirm.
3. Select Actions > Install Oozie ShareLib and click Install Oozie ShareLib to confirm.

Upgrade Sqoop

1. Go to the Sqoop service.
2. Select Actions > Stop and click Stop to confirm.
3. Select Actions > Upgrade Sqoop and click Upgrade Sqoop to confirm.

Restart the Services

1. On the Home > Status tab, click to the right of the cluster name and select Restart.
2. Click the Restart button in the confirmation pop-up that appears. The Command Details window shows the progress of starting services.

Deploy Client Configuration Files

1. On the Home > Status tab, click to the right of the cluster name and select Deploy Client Configuration.
2. Click the Deploy Client Configuration button in the confirmation pop-up that appears.

Remove the Previous CDH Version Packages and Refresh Symlinks

If your previous installation of CDH was done using packages, remove those packages on all hosts on which you installed the parcels and refresh the symlinks so that clients will run the new software versions. Skip this step if your previous installation was using parcels.

1. If Hue is configured to use SQLite as its database:
   1. Stop the Hue service.
   2. Back up the desktop.db to a temporary location before deleting the old Hue Common package. The location of the database can be found in the Hue service Configuration tab under Service > Database > Hue's Database Directory.
     Important: Removing the Hue Common package will remove your Hue database; if you do not back it up you may lose all your Hue user account information.
2. Uninstall the CDH packages on each host:
   • Not including Impala and Search

     Operating System	Command
     RHEL	$ sudo yum remove hadoop hue-common bigtop-jsvc bigtop-tomcat
     SLES	$ sudo zypper remove hadoop hue-common bigtop-jsvc bigtop-tomcat
     Ubuntu or Debian	$ sudo apt-get purge hadoop hue-common bigtop-jsvc bigtop-tomcat

   • Including Impala and Search

     Operating System	Command
     RHEL	$ sudo yum remove hadoop hue-common impala-shell solr-server 'bigtop-*'
     SLES	$ sudo zypper remove hadoop hue-common impala-shell solr-server 'bigtop-*'
     Ubuntu or Debian	$ sudo apt-get purge hadoop hue-common impala-shell solr-server 'bigtop-*'

3. Restart all the Cloudera Manager Agents to force an update of the symlinks to point to the newly installed components on each host:

   $ sudo service cloudera-scm-agent restart

Restore Backed up Hue Database

1. Go to the Hue service.
2. Select Actions > Stop and click Stop to confirm.
3. Copy the backup from the temporary location to the newly created Hue database directory: /opt/cloudera/parcels/CDH-4.x.0-x.cdh4.x.0.p0.xx/share/hue/desktop.
4. Restart the Hue service.