• The JDK must be 64-bit. Do not use a 32-bit JDK.
• The installed JDK must be a supported version as documented in Java Requirements.
• The same version of the JDK must be installed on each cluster host.
• The JDK must be installed at /usr/java/jdk-version.

  Important:

• The RHEL-compatible and Ubuntu operating systems supported by Cloudera Enterprise 6 all use AES-256 encryption by default for tickets. To support AES-256 bit encryption in JDK versions lower than 1.8u161, you must install the Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy File on all cluster and Hadoop user machines. Cloudera Manager can automatically install the policy files, or you can install them manually. For JCE Policy File installation instructions, see the README.txt file included in the jce_policy-x.zip file. JDK 1.8u161 and higher enable unlimited strength encryption by default, and do not require policy files.
• On SLES platforms, do not install or try to use the IBM Java version bundled with the SLES distribution. CDH does not run correctly with that version.

  Note: Cloudera, Inc. acquired Oracle JDK software under the Oracle Binary Code License Agreement. Pursuant to Item D(v)(a) of the SUPPLEMENTAL LICENSE TERMS of the Oracle Binary Code License Agreement, use of JDK software is governed by the terms of the Oracle Binary Code License Agreement. By installing the JDK software, you agree to be bound by these terms. If you do not wish to be bound by these terms, then do not install the Oracle JDK.

After completing Step 1: Configure a Repository for Cloudera Manager, you can install the Oracle JDK on the Cloudera Manager Server host using your package manager as follows:

• RHEL Compatible

  sudo yum install oracle-j2sdk1.8

• SLES

  sudo zypper install oracle-j2sdk1.8

• Ubuntu

  sudo apt-get install oracle-j2sdk1.8

You can use Cloudera Manager to install the JDK on the remaining cluster hosts in an upcoming step. Continue to Step 3: Install Cloudera Manager Server.

The Oracle JDK installer is available both as an RPM-based installer for RPM-based systems, and as a .tar.gz file. These instructions are for the .tar.gz file.

1. Download the .tar.gz file for one of the 64-bit supported versions of the Oracle JDK from Java SE 8 Downloads. (This link is correct at the time of writing, but can change.)
     Note: If you want to download the JDK directly using a utility such as wget, you must accept the Oracle license by configuring headers, which are updated frequently. Blog posts and Q&A sites can be a good source of information on how to download a particular JDK version using wget.
2. Extract the JDK to /usr/java/jdk-version. For example:

   tar xvfz /path/to/jdk-8u<update_version>-linux-x64.tar.gz -C /usr/java/

3. Repeat this procedure on all cluster hosts. After you have finished, continue to Step 3: Install Cloudera Manager Server.

Before installing Cloudera Manager and CDH, perform the steps in this section to install OpenJDK on all hosts in your cluster(s).

  Important: When you install Cloudera Enterprise, Cloudera Manager includes an option to install Oracle JDK. De-select this option before continuing with the installation. .

See Supported JDKs for information on which JDK versions are supported for Cloudera Enterprise releases.

You must install a supported version of OpenJDK. If your deployment uses a version of OpenJDK lower than 1.8.0_181, see TLS Protocol Error with OpenJDK.

  Note: If you intend to enable Auto-TLS, note the following:

You can specify a PEM file containing trusted CA certificates to be imported into the Auto-TLS truststore. If you want to use the certificates in the cacerts truststore that comes with OpenJDK, you must convert the truststore to PEM format first. However, OpenJDK ships with some intermediate certificates that cannot be imported into the Auto-TLS truststore. You must remove these certificates from the PEM file before importing the PEM file into the Auto-TLS truststore. This is not required when upgrading to OpenJDK from a cluster where Auto-TLS has already been enabled.

1. Log in to each host and run the command for the version of the JDK you want to install:

   RHEL

   OpenJDK 8

   su -c yum install java-1.8.0-openjdk-devel

   OpenJDK 11

   su -c yum install java-11-openjdk-devel

   Ubuntu

   OpenJDK 8

   sudo apt-get install openjdk-8-jdk

   OpenJDK 11

   sudo apt-get install openjdk-11-jdk

   SLES

   OpenJDK 8

   sudo zypper install java-1_8_0-openjdk-devel

   OpenJDK 11

   sudo zypper install java-11-openjdk-devel

2. Tune the JDK (OpenJDK 11 only.)

   OpenJDK 11 uses new defaults for garbage collection and other Java options specified when launching Java processes. Due to these changes you may need to tune the garbage collection by adjusting the Java options used to run cluster services, which are configured separately for each service using the service's configuration parameters. To locate the correct parameter, log in to the Cloudera Manager Admin Console, go to the cluster and service you want to configure and search for "Java Configuration Options".

   When using OpenJDK 11, Cloudera Manager and most CDH services use G1GC as the default method of garbage collection. Java 8 used "ConcurrentMarkSweep" (CMS) for garbage collection. When using G1GC, the pauses for garbage collection are shorter, so components will usually be more responsive, but they are more sensitive to JVMs with overcommitted memory usage. See Tuning JVM Garbage Collection.