[JENKINS-70392] Kubernetes client 6.x follow-up compatibility

[Vlatombe]

For compatibility with Kubernetes client 6.x

Also adds RJR based tests as JenkinsRule tests did not catch the classloading issue.

• Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
• Ensure that the pull request title represents the desired changelog entry
• Please describe what you did
• Link to relevant issues in GitHub or Jira
• Link to relevant pull requests, esp. upstream and downstream changes
• Ensure you have provided tests - that demonstrates feature works or fixes the issue

[jglick]

Looks promising. What is missing in RJR to let this run in kind.sh?

[jglick]

I think this is backwards? (Javadoc first, then package statement)

[Vlatombe]

What is missing in RJR to let this run in kind.sh?

See #1290 for the follow-up (I needed to let this one go since the release was broken)

[rpaasche]

I'm still getting this error with 3800.v54b_077b_94b_a_4

2023-01-10 15:49:01 |  hudson.remoting.ProxyException: io.fabric8.kubernetes.client.KubernetesClientException: No httpclient implementations found on the context classloader, please ensure your classpath includes an implementation jar
2023-01-10 15:49:01 |  	at io.fabric8.kubernetes.client.utils.HttpClientUtils.getHttpClientFactory(HttpClientUtils.java:164)
2023-01-10 15:49:01 |  	at io.fabric8.kubernetes.client.utils.HttpClientUtils.createHttpClient(HttpClientUtils.java:145)
2023-01-10 15:49:01 |  	at io.fabric8.kubernetes.client.DefaultKubernetesClient.<init>(DefaultKubernetesClient.java:56)
2023-01-10 15:49:01 |  	at io.fabric8.kubernetes.client.DefaultKubernetesClient.<init>(DefaultKubernetesClient.java:48)
2023-01-10 15:49:01 |  	at org.csanchez.jenkins.plugins.kubernetes.PodTemplateUtils.parseFromYaml(PodTemplateUtils.java:602)
2023-01-10 15:49:01 |  	at org.csanchez.jenkins.plugins.kubernetes.PodTemplateUtils.validateYamlContainerNames(PodTemplateUtils.java:639)
2023-01-10 15:49:01 |  	at org.csanchez.jenkins.plugins.kubernetes.PodTemplateUtils.validateYamlContainerNames(PodTemplateUtils.java:629)
2023-01-10 15:49:01 |  	at org.csanchez.jenkins.plugins.kubernetes.pipeline.PodTemplateStepExecution.start(PodTemplateStepExecution.java:145)

[mobidroid]

Getting the same error when trying to test connection from the Manage Nodes & Clouds > Kubernetes Cloud:

Error testing connection https://<my-cluster> No httpclient implementations found on the context classloader, please ensure your classpath includes an implementation jar

[PatrickGhezali]

Same issue here with this plugin combination:

Kubernetes Client API Plugin 6.3.1-206.v76d3b_6b_14db_b
Kubernetes Credentials Plugin 0.10.0
Kubernetes plugin 3800.v54b_077b_94b_a_4

[Nuc7ear]

Kubernetes Client API Plugin 6.3.1-206.v76d3b_6b_14db_b
Kubernetes Credentials Plugin 0.10.0
Kubernetes plugin 3800.v54b_077b_94b_a_4

Same problem with this version of plugins

[Vlatombe]

Very sorry for these inconvenience, seems like I missed a few more occurrences.

[PatrickGhezali]

Thanks for taking care!

[Vlatombe]

#1291