Jenkins not able to launch the slave due to unrecognizable JAVA_HOME

[Sai Bhargav Kottisa]

Hi,

I have the below machine config

(Master Jenkins)

OS RedHat Enterprise Linux 7.6

openjdk version "11.0.22" 2024-01-16 LTS

path: /usr/lib/jvm/java-11-openjdk-11.0.22.0.7-1.el7_9.x86_64/bin/java

 (Slave Jenkins)

RHEL VERSION=7.9 (Maipo)

openjdk version "12.0.2" 2019-07-16

path: /etc/java/jdk-12.0.2+10/bin/java

 I am facing the below problem while trying to launch an ON premise Linux slave agent 

SSHLauncher{host='md1npdvlnx416', port=22, credentialsId='taf-jenkins', jvmOptions='', javaPath='', prefixStartSlaveCmd='', suffixStartSlaveCmd='', launchTimeoutSeconds=60, maxNumRetries=10, retryWaitTime=15, sshHostKeyVerificationStrategy=hudson.plugins.sshslaves.verifiers.NonVerifyingKeyVerificationStrategy, tcpNoDelay=true, trackCredentials=true} [04/15/24 06:08:54] [SSH] Opening SSH connection to md1npdvlnx416:22. [04/15/24 06:08:54] [SSH] WARNING: SSH Host Keys are not being verified. Man-in-the-middle attacks may be possible against this connection. [04/15/24 06:08:54] [SSH] Authentication successful. [04/15/24 06:08:54] [SSH] The remote user's environment is: Checking Java version in the PATH Java is not in the PATH nor configured with the javaPath setting, Jenkins will try to guess where is Java, this guess will be removed in the future. :Launch agents via SSH [04/15/24 06:08:54] [SSH] Checking java version of /var/lib/jenkins/jenkins-agent/jdk/bin/java Couldn't figure out the Java version of /var/lib/jenkins/jenkins-agent/jdk/bin/java [04/15/24 06:08:54] [SSH] Checking java version of /etc/java/jdk-12.0.2+10/bin/java/bin/java Couldn't figure out the Java version of /etc/java/jdk-12.0.2+10/bin/java/bin/java [04/15/24 06:08:54] [SSH] Checking java version of /etc/java/jdk-12.0.2+10/bin/java/bin/java Couldn't figure out the Java version of /etc/java/jdk-12.0.2+10/bin/java/bin/java [04/15/24 06:08:54] [SSH] Checking java version of java Couldn't figure out the Java version of java [04/15/24 06:08:54] [SSH] Checking java version of /usr/bin/java Couldn't figure out the Java version of /usr/bin/java [04/15/24 06:08:54] [SSH] Checking java version of /usr/java/default/bin/java Couldn't figure out the Java version of /usr/java/default/bin/java [04/15/24 06:08:54] [SSH] Checking java version of /usr/java/latest/bin/java Couldn't figure out the Java version of /usr/java/latest/bin/java [04/15/24 06:08:54] [SSH] Checking java version of /usr/local/bin/java Couldn't figure out the Java version of /usr/local/bin/java [04/15/24 06:08:54] [SSH] Checking java version of /usr/local/java/bin/java Couldn't figure out the Java version of /usr/local/java/bin/java java.io.IOException: Java not found on hudson.slaves.SlaveComputer Install Java 8 or Java 11 on the Agent. at hudson.plugins.sshslaves.JavaVersionChecker.resolveJava(JavaVersionChecker.java:83) at hudson.plugins.sshslaves.SSHLauncher.lambda$launch$0(SSHLauncher.java:460) at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) at java.base/java.lang.Thread.run(Thread.java:829) [04/15/24 06:08:54] Launch failed - cleaning up connection [04/15/24 06:08:54] [SSH] Connection closed.

SSHLauncher{host='md1npdvlnx416', port=22, credentialsId='taf-jenkins', jvmOptions='', javaPath='', prefixStartSlaveCmd='', suffixStartSlaveCmd='', launchTimeoutSeconds=60, maxNumRetries=10, retryWaitTime=15, sshHostKeyVerificationStrategy=hudson.plugins.sshslaves.verifiers.NonVerifyingKeyVerificationStrategy, tcpNoDelay=true, trackCredentials=true} [04/15/24 06:11:13] [SSH] Opening SSH connection to md1npdvlnx416:22. [04/15/24 06:11:13] [SSH] WARNING: SSH Host Keys are not being verified. Man-in-the-middle attacks may be possible against this connection.

[04/15/24 06:11:13] [SSH] Authentication successful. [04/15/24 06:11:13] [SSH] The remote user's environment is: Checking Java version in the PATH Java is not in the PATH nor configured with the javaPath setting, Jenkins will try to guess where is Java, this guess will be removed in the future. :Launch agents via SSH [04/15/24 06:11:13] [SSH] Checking java version of /var/lib/jenkins/jenkins-agent/jdk/bin/java Couldn't figure out the Java version of /var/lib/jenkins/jenkins-agent/jdk/bin/java [04/15/24 06:11:13] [SSH] Checking java version of /etc/java/jdk-12.0.2+10/bin/java/bin/java Couldn't figure out the Java version of /etc/java/jdk-12.0.2+10/bin/java/bin/java [04/15/24 06:11:13] [SSH] Checking java version of /etc/java/jdk-12.0.2+10/bin/java/bin/java Couldn't figure out the Java version of /etc/java/jdk-12.0.2+10/bin/java/bin/java [04/15/24 06:11:13] [SSH] Checking java version of java Couldn't figure out the Java version of java [04/15/24 06:11:13] [SSH] Checking java version of /usr/bin/java Couldn't figure out the Java version of /usr/bin/java [04/15/24 06:11:13] [SSH] Checking java version of /usr/java/default/bin/java Couldn't figure out the Java version of /usr/java/default/bin/java [04/15/24 06:11:13] [SSH] Checking java version of /usr/java/latest/bin/java Couldn't figure out the Java version of /usr/java/latest/bin/java [04/15/24 06:11:13] [SSH] Checking java version of /usr/local/bin/java Couldn't figure out the Java version of /usr/local/bin/java [04/15/24 06:11:13] [SSH] Checking java version of /usr/local/java/bin/java Couldn't figure out the Java version of /usr/local/java/bin/java java.io.IOException: Java not found on hudson.slaves.SlaveComputer Install Java 8 or Java 11 on the Agent. at hudson.plugins.sshslaves.JavaVersionChecker.resolveJava(JavaVersionChecker.java:83) at hudson.plugins.sshslaves.SSHLauncher.lambda$launch$0(SSHLauncher.java:460) at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) at java.base/java.lang.Thread.run(Thread.java:829) [04/15/24 06:11:13] Launch failed - cleaning up connection [04/15/24 06:11:13] [SSH] Connection closed.

SSHLauncher{host='md1npdvlnx416', port=22, credentialsId='taf-jenkins', jvmOptions='', javaPath='', prefixStartSlaveCmd='', suffixStartSlaveCmd='', launchTimeoutSeconds=60, maxNumRetries=10, retryWaitTime=15, sshHostKeyVerificationStrategy=hudson.plugins.sshslaves.verifiers.NonVerifyingKeyVerificationStrategy, tcpNoDelay=true, trackCredentials=true} [04/15/24 06:08:54] [SSH] Opening SSH connection to md1npdvlnx416:22. [04/15/24 06:08:54] [SSH] WARNING: SSH Host Keys are not being verified. Man-in-the-middle attacks may be possible against this connection. [04/15/24 06:08:54] [SSH] Authentication successful. [04/15/24 06:08:54] [SSH] The remote user's environment is: Checking Java version in the PATH Java is not in the PATH nor configured with the javaPath setting, Jenkins will try to guess where is Java, this guess will be removed in the future. :Launch agents via SSH [04/15/24 06:08:54] [SSH] Checking java version of /var/lib/jenkins/jenkins-agent/jdk/bin/java Couldn't figure out the Java version of /var/lib/jenkins/jenkins-agent/jdk/bin/java [04/15/24 06:08:54] [SSH] Checking java version of /etc/java/jdk-12.0.2+10/bin/java/bin/java Couldn't figure out the Java version of /etc/java/jdk-12.0.2+10/bin/java/bin/java [04/15/24 06:08:54] [SSH] Checking java version of /etc/java/jdk-12.0.2+10/bin/java/bin/java Couldn't figure out the Java version of /etc/java/jdk-12.0.2+10/bin/java/bin/java [04/15/24 06:08:54] [SSH] Checking java version of java Couldn't figure out the Java version of java [04/15/24 06:08:54] [SSH] Checking java version of /usr/bin/java Couldn't figure out the Java version of /usr/bin/java [04/15/24 06:08:54] [SSH] Checking java version of /usr/java/default/bin/java Couldn't figure out the Java version of /usr/java/default/bin/java [04/15/24 06:08:54] [SSH] Checking java version of /usr/java/latest/bin/java Couldn't figure out the Java version of /usr/java/latest/bin/java [04/15/24 06:08:54] [SSH] Checking java version of /usr/local/bin/java Couldn't figure out the Java version of /usr/local/bin/java [04/15/24 06:08:54] [SSH] Checking java version of /usr/local/java/bin/java Couldn't figure out the Java version of /usr/local/java/bin/java java.io.IOException: Java not found on hudson.slaves.SlaveComputer Install Java 8 or Java 11 on the Agent. at hudson.plugins.sshslaves.JavaVersionChecker.resolveJava(JavaVersionChecker.java:83) at hudson.plugins.sshslaves.SSHLauncher.lambda$launch$0(SSHLauncher.java:460) at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) at java.base/java.lang.Thread.run(Thread.java:829) [04/15/24 06:08:54] Launch failed - cleaning up connection [04/15/24 06:08:54] [SSH] Connection closed.

SSHLauncher{host='md1npdvlnx416', port=22, credentialsId='taf-jenkins', jvmOptions='', javaPath='', prefixStartSlaveCmd='', suffixStartSlaveCmd='', launchTimeoutSeconds=60, maxNumRetries=10, retryWaitTime=15, sshHostKeyVerificationStrategy=hudson.plugins.sshslaves.verifiers.NonVerifyingKeyVerificationStrategy, tcpNoDelay=true, trackCredentials=true} [04/15/24 06:11:13] [SSH] Opening SSH connection to md1npdvlnx416:22. [04/15/24 06:11:13] [SSH] WARNING: SSH Host Keys are not being verified. Man-in-the-middle attacks may be possible against this connection.

[04/15/24 06:11:13] [SSH] Authentication successful. [04/15/24 06:11:13] [SSH] The remote user's environment is: Checking Java version in the PATH Java is not in the PATH nor configured with the javaPath setting, Jenkins will try to guess where is Java, this guess will be removed in the future. :Launch agents via SSH [04/15/24 06:11:13] [SSH] Checking java version of /var/lib/jenkins/jenkins-agent/jdk/bin/java Couldn't figure out the Java version of /var/lib/jenkins/jenkins-agent/jdk/bin/java [04/15/24 06:11:13] [SSH] Checking java version of /etc/java/jdk-12.0.2+10/bin/java/bin/java Couldn't figure out the Java version of /etc/java/jdk-12.0.2+10/bin/java/bin/java [04/15/24 06:11:13] [SSH] Checking java version of /etc/java/jdk-12.0.2+10/bin/java/bin/java Couldn't figure out the Java version of /etc/java/jdk-12.0.2+10/bin/java/bin/java [04/15/24 06:11:13] [SSH] Checking java version of java Couldn't figure out the Java version of java [04/15/24 06:11:13] [SSH] Checking java version of /usr/bin/java Couldn't figure out the Java version of /usr/bin/java [04/15/24 06:11:13] [SSH] Checking java version of /usr/java/default/bin/java Couldn't figure out the Java version of /usr/java/default/bin/java [04/15/24 06:11:13] [SSH] Checking java version of /usr/java/latest/bin/java Couldn't figure out the Java version of /usr/java/latest/bin/java [04/15/24 06:11:13] [SSH] Checking java version of /usr/local/bin/java Couldn't figure out the Java version of /usr/local/bin/java [04/15/24 06:11:13] [SSH] Checking java version of /usr/local/java/bin/java Couldn't figure out the Java version of /usr/local/java/bin/java java.io.IOException: Java not found on hudson.slaves.SlaveComputer Install Java 8 or Java 11 on the Agent. at hudson.plugins.sshslaves.JavaVersionChecker.resolveJava(JavaVersionChecker.java:83) at hudson.plugins.sshslaves.SSHLauncher.lambda$launch$0(SSHLauncher.java:460) at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) at java.base/java.lang.Thread.run(Thread.java:829) [04/15/24 06:11:13] Launch failed - cleaning up connection [04/15/24 06:11:13] [SSH] Connection closed. even though i have java installed and i have configured in TOOLS section as shown below

but still jenkins not recognizing JAVA path

so could anyone please help as it is urgent

[Mark Waite]

On Monday, April 15, 2024 at 7:09:03 AM UTC-7 Sai wrote:

Hi,

I have the below machine config

(Master Jenkins)

OS RedHat Enterprise Linux 7.6

openjdk version "11.0.22" 2024-01-16 LTS

path: /usr/lib/jvm/java-11-openjdk-11.0.22.0.7-1.el7_9.x86_64/bin/java

The Jenkins project stopped supporting RHEL 7 in Nov 2023.  RHEL 7.9 is the most recent release of RHEL 7.  You're running RHEL 7.6, an outdated version of an unsupported operating system.  It might work, but the Jenkins project no longer tests or verifies that operating system 

 

 (Slave Jenkins)

RHEL VERSION=7.9 (Maipo)

openjdk version "12.0.2" 2019-07-16

path: /etc/java/jdk-12.0.2+10/bin/java

Jenkins has never supported Java 12.  I don't recall anyone ever doing any Jenkins testing or Jenkins development with Java 12.  Java 12 is also not supported by the OpenJDK project.

Jenkins currently supports Java 11, Java 17, and Java 21.  

The installation location that you are listing for Java 12 is unexpected.  Applications (like Java) are not intended to be installed in the "/etc" directory.  If you install Java 11 on the agent operating system using either Eclipse Temurin packages or operating system packages, it will not place Java in "/etc".

Your options include:

• Install Java 11 on the agent and plan for future operating system upgrades to replace RHEL 7 with something that is supported
• Continue attempts with Java 12 on the agent after assuring that Java 12 is actually installed.  You'll be running an unsupported, untested Jenkins configuration with an unsupported Java version
• Install Java 17 on the controller and on the agent  and plan for future operating system upgrades to replace RHEL 7 with something that is supported
• Install Java  21 on the controller and on the agent  and plan for future operating system upgrades to replace RHEL 7 with something that is supported

[Ivan Fernandez Calvo]

>Jenkins not able to launch the slave due to unrecognizable JAVA_HOME

Stop using Slave and use Agent as a name for the Build Agents attached to the Jenkins Controller (no longer master)

>so could anyone please help as it is urgent

This is a User group, so NOTHING here is urgent. If someone can help, I will do it, but it is not mandatory, and NOBODY can request urgency here.

And now we can continue with your question. 

As Mark said Java 12 was never supported and is not a LTS. 

It is recommended that the Jenkins Controller and the Build Agent process be run in the same Java version to avoid compatibility issues.

As the message said, the plugin tried to find the `java` binary in the PATH, which was impossible, so it tried to use some hardcoded paths. The correct way is to configure your build agent to have a Java binary in the PATH. How to do it depends on your distribution and the shell you use for the user who connects through SSH. There is plenty of documentation about how to set up the environment of a system/user in Linux/Unix.

Tools location is not used to locate the Java version to run the build agent process, it is used on jobs, so no matter the configuration you put there is not used.

[Sai Bhargav Kottisa]

Hi,

I have upgraded java on both the controller and agent machines to OpenJdk 17 and tried to launch again via ssh but still i am getting the same error

Controller machine(/usr/lib/jvm/Openjdk_17.0.6.0/bin/java

                                     drwxr-xr-x 10 root root 131 Jan 13  2023 Openjdk_17.0.6.0 )

Agent machine (/etc/java/Openjdk_17.0.6.0/bin/java

                                     drwxr-xr-x 10 root    root      131 Jan 14  2023 Openjdk_17.0.6.0)

SSHLauncher{host='md1npdvlnx416.dev.corp.local', port=22, credentialsId='taf-jenkins', jvmOptions='', javaPath='', prefixStartSlaveCmd='', suffixStartSlaveCmd='', launchTimeoutSeconds=60, maxNumRetries=10, retryWaitTime=15, sshHostKeyVerificationStrategy=hudson.plugins.sshslaves.verifiers.NonVerifyingKeyVerificationStrategy, tcpNoDelay=true, trackCredentials=true} [04/18/24 12:27:46] [SSH] Opening SSH connection to md1npdvlnx416.dev.corp.local:22. [04/18/24 12:27:46] [SSH] WARNING: SSH Host Keys are not being verified. Man-in-the-middle attacks may be possible against this connection. [04/18/24 12:27:46] [SSH] Authentication successful. [04/18/24 12:27:46] [SSH] The remote user's environment is: Checking Java version in the PATH Java is not in the PATH nor configured with the javaPath setting, Jenkins will try to guess where is Java, this guess will be removed in the future. :Launch agents via SSH [04/18/24 12:27:46] [SSH] Checking java version of /var/lib/jenkins/jdk/bin/java Couldn't figure out the Java version of /var/lib/jenkins/jdk/bin/java [04/18/24 12:27:46] [SSH] Checking java version of java Couldn't figure out the Java version of java [04/18/24 12:27:46] [SSH] Checking java version of /usr/bin/java Couldn't figure out the Java version of /usr/bin/java [04/18/24 12:27:46] [SSH] Checking java version of /usr/java/default/bin/java Couldn't figure out the Java version of /usr/java/default/bin/java [04/18/24 12:27:46] [SSH] Checking java version of /usr/java/latest/bin/java Couldn't figure out the Java version of /usr/java/latest/bin/java [04/18/24 12:27:46] [SSH] Checking java version of /usr/local/bin/java Couldn't figure out the Java version of /usr/local/bin/java [04/18/24 12:27:46] [SSH] Checking java version of /usr/local/java/bin/java Couldn't figure out the Java version of /usr/local/java/bin/java java.io.IOException: Java not found on hudson.slaves.SlaveComputer@3242743c. Install Java 8 or Java 11 on the Agent. at hudson.plugins.sshslaves.JavaVersionChecker.resolveJava(JavaVersionChecker.java:83) at hudson.plugins.sshslaves.SSHLauncher.lambda$launch$0(SSHLauncher.java:460) at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) at java.base/java.lang.Thread.run(Thread.java:829) [04/18/24 12:27:46] Launch failed - cleaning up connection [04/18/24 12:27:46] [SSH] Connection closed.

And also i have tried Launch agent by connecting to controller option

but i am getting below error

java -jar agent.jar -url http://mo1csgw2321:8080/ -secret <secret> -name "TAF-child" -workDir "/var/lib/jenkins"
Apr 18, 2024 4:11:50 PM org.jenkinsci.remoting.engine.WorkDirManager initializeWorkDir
INFO: Using /var/lib/jenkins/remoting as a remoting work directory
Apr 18, 2024 4:11:51 PM org.jenkinsci.remoting.engine.WorkDirManager setupLogging
INFO: Both error and output logs will be printed to /var/lib/jenkins/remoting
Apr 18, 2024 4:11:51 PM hudson.remoting.Launcher createEngine
INFO: Setting up agent: TAF-child
Apr 18, 2024 4:11:51 PM hudson.remoting.Engine startEngine
INFO: Using Remoting version: 3206.vb_15dcf73f6a_9
Apr 18, 2024 4:11:51 PM org.jenkinsci.remoting.engine.WorkDirManager initializeWorkDir
INFO: Using /var/lib/jenkins/remoting as a remoting work directory
Apr 18, 2024 4:11:51 PM hudson.remoting.Launcher$CuiListener status
INFO: Locating server among [http:// mo1csgw2321:8080/]
Apr 18, 2024 4:11:51 PM hudson.remoting.Launcher$CuiListener status
INFO: Could not locate server among [ http:// mo1csgw2321:8080/  ]; waiting 10 seconds before retry
java.io.IOException: http:// mo1csgw2321:8080/tcpSlaveAgentListener/ is invalid: 404 Not Found
        at org.jenkinsci.remoting.engine.JnlpAgentEndpointResolver.resolve(JnlpAgentEndpointResolver.java:222)
        at hudson.remoting.Engine.innerRun(Engine.java:809)
        at hudson.remoting.Engine.run(Engine.java:563)

[Ivan Fernandez Calvo]

[SSH] The remote user's environment is: Checking Java version in the PATH Java is not in the PATH nor configured with the javaPath setting,

What happens if you enter by SSH in the agent with the same user you use to connect the Jenkins controller and execute java?

>ssh my-jenkins-user@my-ssh-agent

>java

I will guess

>command not found

[Dirk Heinrichs]

Am Donnerstag, dem 18.04.2024 um 09:40 -0700 schrieb Sai Bhargav Kottisa:

Agent machine (/etc/java/Openjdk_17.0.6.0/bin/java

                                     drwxr-xr-x 10 root    root      131 Jan 14  2023Openjdk_17.0.6.0)

As already written by Mark, you should NOT install things into /etc. It's neither meant for storing binaries (this is Linux, not HPUX), nor is it on the PATH, thus it cannot be found. If you install it from distribution packages, it will be installed into the correct location, where it can then be found when you launch the agent.

Otherwise, provide the full path to it in the agent configuration.

HTH...

Dirk

-- 

Dirk Heinrichs

Senior Systems Engineer, Delivery Pipeline

OpenText ™ Discovery | Recommind

Phone: +49 2226 15966 18

Email: dhei...@opentext.com

Website: www.recommind.de

Recommind GmbH, Von-Liebig-Straße 1, 53359 Rheinbach

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[Maciej Jaros]

Just do this on the agent:

• Get JDK 17 from Adoptium (Linux x64 in my case).
• Unpack to /var/jenkins.
• Rename unpacked “jdk[version]” to “jdk”.
• Check: /var/jenkins/jdk/bin/java -version

Jenkins agent will use /var/jenkins/jdk/bin/java over any other version.

Cheers,
Nux

Sai Bhargav Kottisa (2024-04-18 18:40):