Custom Java settings

Sergei Tikhomirov

Contents

Create a script to set JAVA_HOME
Create a symlink to unify the path to JDK
Change the JAVA_HOME path in Impala
Configure alternatives (AltLinux)

NOTE

In order for the ADH version 3.2.4.1.b3 components to work correctly with a custom JDK, complete the steps below.

Create a script to set JAVA_HOME

Create a new script in the etc/profile.d catalog, e.g. etc/profile.d/set_java_home.sh. You can use a text editor to do so.
```
$ sudo vi /etc/profile.d/set_java_home.sh
```
Add the following lines to the file:
```
#!/bin/bash
export JAVA_HOME=<jdk_path>
export PATH=$PATH:$JAVA_HOME/bin
```
where <jdk_path> is the path to your custom JDK.

Make the script executable.

$ sudo chmod +x /etc/profile.d/set_java_home.sh

To apply the changes, restart the system or run the source command for your script in all active sessions.
```
$ source /etc/profile.d/set_java_home.sh
```
After you’ve applied the changes, it’s recommended to check Java installation by running the commands below to determine that the correct Java version is used:
```
$ java -version
$ javac -version
```

Create a symlink to unify the path to JDK

Open the console on each server where the ADH components are installed (or where you plan to install them).

Run the following command to create a symbolic link from a custom JDK path to the standard path that is expected by bigtop:

$ if [ -e /usr/java/jdk1.8 ] || [ -L /usr/java/jdk1.8 ]; then
    echo "File or symlink already exists at /usr/java/jdk1.8"
else
    sudo ln -s <jdk_path> /usr/java/jdk1.8
    echo "Symlink created successfully"
fi

Change the JAVA_HOME path in Impala

Make sure that the bigtop-utils package is installed on the Impala host.
In ADCM, open the Impala service configuration of your cluster and open the impala-env.sh text parameter.
Change the export JAVA_HOME=/usr/lib/jvm/jre string to source /usr/lib/bigtop-utils/bigtop-detect-javahome. It allows bigtop-detect-javahome from the bigtop-utils package to automatically detect an installed Java path.

Configure alternatives (AltLinux)

If you use the alternatives in AltLinux, complete the steps below:

Create a configuration file in /etc/alternatives/packages.d. For example:
```
$ sudo vim /etc/alternatives/packages.d/zulu-8
```

Add the following lines to the file:

/usr/bin/java   /usr/lib/jvm/zulu-8/jre/bin/java        1800340
/usr/bin/jjs    /usr/lib/jvm/zulu-8/jre/bin/jjs          /usr/lib/jvm/zulu-8/jre/bin/java
/usr/bin/keytool        /usr/lib/jvm/zulu-8/jre/bin/keytool      /usr/lib/jvm/zulu-8/jre/bin/java
/usr/bin/policytool     /usr/lib/jvm/zulu-8/jre/bin/policytool   /usr/lib/jvm/zulu-8/jre/bin/java
/usr/bin/servertool     /usr/lib/jvm/zulu-8/jre/bin/servertool   /usr/lib/jvm/zulu-8/jre/bin/java
/usr/bin/pack200        /usr/lib/jvm/zulu-8/jre/bin/pack200      /usr/lib/jvm/zulu-8/jre/bin/java
/usr/bin/unpack200      /usr/lib/jvm/zulu-8/jre/bin/unpack200    /usr/lib/jvm/zulu-8/jre/bin/java
/usr/bin/orbd   /usr/lib/jvm/zulu-8/jre/bin/orbd         /usr/lib/jvm/zulu-8/jre/bin/java
/usr/bin/rmid   /usr/lib/jvm/zulu-8/jre/bin/rmid         /usr/lib/jvm/zulu-8/jre/bin/java
/usr/bin/rmiregistry    /usr/lib/jvm/zulu-8/jre/bin/rmiregistry  /usr/lib/jvm/zulu-8/jre/bin/java
/usr/bin/tnameserv      /usr/lib/jvm/zulu-8/jre/bin/tnameserv    /usr/lib/jvm/zulu-8/jre/bin/java
/usr/lib/jvm/jre        /usr/lib/jvm/zulu-8/jre                  /usr/lib/jvm/zulu-8/jre/bin/java
alternatives-update

Update the alternatives system.
```
$ sudo alternatives-update
```
Check the settings. If everything was done correctly, it will allow the system to correctly manage the connections and versions of various Java executables.

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