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I have installed a k8s cluster (v1.25.4+k3s1) and I have deployed a jenkins image to that cluster (using this guide) which means that I have the following installed:

Name Version
Jenkins v2.375.1
jvm 11.0.17+8
Kubernetes plugin 3743.v1fa_4c724c3b_7

When I then try to set up workers on this setup using another guide, I get this error (when starting the job):

Jan 10, 2023 7:47:16 PM WARNING org.csanchez.jenkins.plugins.kubernetes.pod.retention.Reaper watchCloud

failed to set up watcher on kubernetes
io.fabric8.kubernetes.client.KubernetesClientException: No httpclient implementations found on the context classloader, please ensure your classpath includes an implementation jar
at io.fabric8.kubernetes.client.utils.HttpClientUtils.getHttpClientFactory(HttpClientUtils.java:164)
at io.fabric8.kubernetes.client.utils.HttpClientUtils.createHttpClient(HttpClientUtils.java:145)
at io.fabric8.kubernetes.client.DefaultKubernetesClient.<init>(DefaultKubernetesClient.java:56)
at org.csanchez.jenkins.plugins.kubernetes.KubernetesFactoryAdapter.createClient(KubernetesFactoryAdapter.java:147)
at org.csanchez.jenkins.plugins.kubernetes.KubernetesClientProvider.createClient(KubernetesClientProvider.java:59)
at org.csanchez.jenkins.plugins.kubernetes.KubernetesCloud.connect(KubernetesCloud.java:523)
at org.csanchez.jenkins.plugins.kubernetes.pod.retention.Reaper.watchCloud(Reaper.java:220)
at org.csanchez.jenkins.plugins.kubernetes.pod.retention.Reaper.preLaunch(Reaper.java:122)
at hudson.slaves.SlaveComputer.lambda$_connect$0(SlaveComputer.java:296)
at jenkins.util.ContextResettingExecutorService$2.call(ContextResettingExecutorService.java:48)
at jenkins.security.ImpersonatingExecutorService$2.call(ImpersonatingExecutorService.java:82)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at java.base/java.lang.Thread.run(Thread.java:829)

Jan 10, 2023 7:47:16 PM WARNING org.csanchez.jenkins.plugins.kubernetes.KubernetesLauncher launch

Error in provisioning; agent=KubernetesSlave name: kube-slave-tq3z1, template=PodTemplate{id='282a0649-b2c7-4a9b-9ee2-0721a8da7ed7', name='kube-slave', namespace='devops-workers', label='kube-slave'}
io.fabric8.kubernetes.client.KubernetesClientException: No httpclient implementations found on the context classloader, please ensure your classpath includes an implementation jar
at io.fabric8.kubernetes.client.utils.HttpClientUtils.getHttpClientFactory(HttpClientUtils.java:164)
at io.fabric8.kubernetes.client.utils.HttpClientUtils.createHttpClient(HttpClientUtils.java:145)
at io.fabric8.kubernetes.client.DefaultKubernetesClient.<init>(DefaultKubernetesClient.java:56)
at org.csanchez.jenkins.plugins.kubernetes.KubernetesFactoryAdapter.createClient(KubernetesFactoryAdapter.java:147)
at org.csanchez.jenkins.plugins.kubernetes.KubernetesClientProvider.createClient(KubernetesClientProvider.java:59)
at org.csanchez.jenkins.plugins.kubernetes.KubernetesCloud.connect(KubernetesCloud.java:523)
at org.csanchez.jenkins.plugins.kubernetes.KubernetesLauncher.launch(KubernetesLauncher.java:120)
at hudson.slaves.SlaveComputer.lambda$_connect$0(SlaveComputer.java:298)
at jenkins.util.ContextResettingExecutorService$2.call(ContextResettingExecutorService.java:48)
at jenkins.security.ImpersonatingExecutorService$2.call(ImpersonatingExecutorService.java:82)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at java.base/java.lang.Thread.run(Thread.java:829)

Jan 10, 2023 7:47:16 PM INFO org.csanchez.jenkins.plugins.kubernetes.KubernetesSlave _terminate

Terminating Kubernetes instance for agent kube-slave-tq3z1

Jan 10, 2023 7:47:16 PM INFO hudson.slaves.NodeProvisioner update

kube-slave-tq3z1 provisioning successfully completed. We have now 2 computer(s)

To experiment I tried to run this script (inspired by this answer) in the Script Console:

@Grab(group='io.fabric8', module='kubernetes-client', version='6.3.1')
@Grab(group='io.fabric8', module='kubernetes-client-api', version='6.3.1')
@Grab(group='io.fabric8', module='kubernetes-httpclient-jdk', version='6.3.1')

import io.fabric8.kubernetes.client.KubernetesClient;
import io.fabric8.kubernetes.client.KubernetesClientBuilder;

KubernetesClient client = new KubernetesClientBuilder().build()

Which gives the same error:

io.fabric8.kubernetes.client.KubernetesClientException: No httpclient implementations found on the context classloader, please ensure your classpath includes an implementation jar

I would prefer not to have to make manual steps to inject jar files into a ready image, so am I missing another Jenkins plugin, or can I have missed something else?

1 Answer 1

3

Upgrade jenkins kubernetes plugin to 3802 and it should work. At least the No httpclient implementations found on the context classloader is addressed by that release.

References:

1
  • hmm that version was not available when i made the post - I see it now
    – JoSSte
    Jan 11, 2023 at 14:36

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