Document that local images can run with 'Never pull'

[HenkPoley]

Issue #599 mentions this option, but it's not documented in the interface. Took me a few months to find.

Given that you need to click the question marks to expand this text, it will probably still not be found by people. But hey, maybe this gets picked up by some documentation generator, I don't know.

Testing done

Do you want UI tests? (and how do I do that?)

Submitter checklist

• 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

[MarkEWaite]

Thanks!

[MarkEWaite]

Issue #599 mentions this option, but it's not documented in the interface. Took me a few months to find.

Would you be willing to add additional text to the README.md so that it appears on the plugin documentation page. This pull request is accepted whether or not you add text to the README. Let me know if you want me to merge immediately or if I should wait for additional text in the README.

[HenkPoley]

I'll check that readme.

[HenkPoley]

I wrote something, are you happy with that?

[HenkPoley]

Probably for another PR, a code PR, and not for me to write, but it would be nice if something around that com.github.dockerjava.api.exception.NotFoundException error message would trigger a hint that you may need to set to 'Never pull'.

I think you could even probe the local Docker to see if the image does exist locally.

[MarkEWaite]

Thanks! That looks great.

[HenkPoley]

Another nice thing to add to the documentation would be what minimal set of UNIX utilities Jenkins expects on the 'cloud' image.

I've now "willy-nilly" installed openjdk 17, git, and a bunch of things like wget, curl, openssh-clients, zip, unzip. And it seems to have made it happy. But I did no ablation study. Added a 'jenkins' user as well. These kind of things. I've a hard time tracking down what's necessary.

[MarkEWaite]

Another nice thing to add to the documentation would be what minimal set of UNIX utilities Jenkins expects on the 'cloud' image.

The Jenkins agent container images (inbound and ssh) include the base set of UNIX utilities for Jenkins use.

I've now "willy-nilly" installed openjdk 17, git, and a bunch of things like wget, curl, openssh-clients, zip, unzip. And it seems to have made it happy. But I did no ablation study. Added a 'jenkins' user as well. These kind of things. I've a hard time tracking down what's necessary.

Deriving your agent container image from the Jenkins images will avoid that type of issue. If you want minimal components, use the Alpine container images. If you need glibc and want minimal components, choose the Debian images.