Kubernetes Agent page is stuck in loading waiting on 'KubernetesLauncher.isLaunchSupported'

Issue

The status page of Kubernetes agents does not load
Associated threads threads are BLOCKED on org.csanchez.jenkins.plugins.kubernetes.KubernetesLauncher.isLaunchSupported:

"Handling GET /cm-1/computer/pipeline%2D1%2D9%2D99tv7%2D528bm%2Drc4mf/ from 1.2.3.4 : Jetty (winstone)-151640 Computer/index.jelly ComputerLauncher/app-bar-controls.jelly" id=151640 state=BLOCKED
    - waiting to lock <0x5423e08a> (a com.cloudbees.jenkins.plugins.kube.ListenableKubernetesLauncher)
     owned by Computer.threadPoolForRemoting [#186] id=151507
    at org.csanchez.jenkins.plugins.kubernetes.KubernetesLauncher.isLaunchSupported(KubernetesLauncher.java:91)
    at hudson.slaves.SlaveComputer.isLaunchSupported(SlaveComputer.java:247)
    [...]

"Computer.threadPoolForRemoting [#186]" id=151507 state=TIMED_WAITING
    at java.base@11.0.21/java.lang.Thread.sleep(Native Method)
    at org.csanchez.jenkins.plugins.kubernetes.KubernetesLauncher.launch(KubernetesLauncher.java:232)
    at com.cloudbees.jenkins.plugins.kube.ListenableKubernetesLauncher.launch(ListenableKubernetesLauncher.java:27)
    at hudson.slaves.SlaveComputer.lambda$_connect$0(SlaveComputer.java:297)
    at hudson.slaves.SlaveComputer$$Lambda$1230/0x00000008414c0840.call(Unknown Source)
    at jenkins.util.ContextResettingExecutorService$2.call(ContextResettingExecutorService.java:46)
    at jenkins.security.ImpersonatingExecutorService$2.call(ImpersonatingExecutorService.java:80)
    at java.base@11.0.21/java.util.concurrent.FutureTask.run(FutureTask.java:264)
    at java.base@11.0.21/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
    at java.base@11.0.21/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
    at java.base@11.0.21/java.lang.Thread.run(Thread.java:829)

Environment

CloudBees CI on modern cloud platforms - managed controller >= 2.414.2.2 and < 2.426.3.3
CloudBees CI on modern cloud platforms - operations center >= 2.414.2.2 and < 2.426.3.3
CloudBees CI on traditional platforms - client controller>= 2.414.2.2 and < 2.426.3.3
CloudBees CI on traditional platforms - operations center >= 2.414.2.2 and < 2.426.3.3
Jenkins®
Kubernetes plugin >= 4007.v633279962016 and < 4151.v6fa_f0fb_0b_4c9

Related Issue(s)

Prevent lock contention on KubernetesLauncher#isLaunchSupported (#1479)

Resolution

The lock contention problem has been fixed in version 4151.v6fa_f0fb_0b_4c9 of the kubernetes plugin.

The recommended solution is to upgrade CloudBees CI to version 2.426.3.3 or later.

This article is part of our Knowledge Base and is provided for guidance-based purposes only. The solutions or workarounds described here are not officially supported by CloudBees and may not be applicable in all environments. Use at your own discretion, and test changes in a safe environment before applying them to production systems.