Custom Java settings

Olga Semme

Contents

Install Java
Use custom Java

This article describes the installation and configuration of a custom version of Java for the ADS cluster.

Install Java

Below is an example of installing Java 21.

Download the Java version you need on all hosts:

$ wget https://download.oracle.com/java/21/archive/jdk-21.0.2_linux-x64_bin.tar.gz

Create a directory for custom Java on all hosts:
```
$ mkdir -p /tmp/jvm-example
```

Unpack the package in the created directory on all hosts:

$ sudo tar -xzf jdk-21.0.2_linux-x64_bin.tar.gz -C /tmp/jvm-example

Set permissions for the directory:

$ sudo chmod 755 /tmp/jvm-example/jdk-21.0.2

Check Java installation by running the command below to determine that the required Java version is used:

$ /tmp/jvm-example/jdk-21.0.2/bin/java --version

The output:

java 21.0.2 2024-01-16 LTS
Java(TM) SE Runtime Environment (build 21.0.2+13-LTS-58)
Java HotSpot(TM) 64-Bit Server VM (build 21.0.2+13-LTS-58, mixed mode, sharing)

Use custom Java

When using custom Java, before running the Install or Update cluster actions in ADS after loading the new bundle, perform the following steps:

On the Clusters page, select the desired cluster.
Go to the cluster confgiuration page.
Expand the group with repositories for the selected operating system (for example, Ubuntu 22 repositories), select the arenadata_java repository, and expand its settings. Set the enabled parameter to false.

Disabling the Arenadata Java repository
Check the Advanced flag and expand the Custom Java config group.

Custom Java config
Open AD runtime utils config template and edit it by adding the path to JAVA_HOME in the paths list for the required Java version (only part of the template is provided, including Java 21, installed in the example above):
```
default:
  runtimes:
    java:
      version: "{{ java_default_version }}"
      env_var: JAVA_HOME

autodetect:
  runtimes:
...
"21":
        env_var: JAVA21_HOME
        paths:
          - /tmp/jvm-example/jdk-21.0.2
...
```
The order of the directory list matters — the first directory where Java is found will be used as JAVA_HOME.
Click Apply and confirm the changes to the cluster configuration by clicking Save.

When launching the Install or Update cluster action, in the window that opens, in the list of required installation parameters, set the Install OpenJDK parameter to false.

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