Document how to add Windows self-hosted runners #1608
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| RUN powershell choco feature enable -n allowGlobalConfirmation | ||
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| CMD [ "pwsh", "-c", "./config.cmd --name $env:RUNNER_NAME --url https://github.com/$env:RUNNER_REPO --token $env:RUNNER_TOKEN --labels $env:RUNNER_LABELS --unattended --replace --ephemeral; ./run.cmd"] |
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@ian-flores Hey! Thanks for submitting this awesome pull request 🙏
Although I'm not an expert in managing Windows machines as K8s nodes, I tried my best to review this and everything looked generally good.
My only concern is in this line- how does it handle termination signals sent by Kubernetes?
On Linux, the PID 0 of each container gets SIGTERM on pod termination and usually, the PID 0 should gracefully stop all its child processes. We implement this for ARC with dumb-init, as you can see at:
https://github.com/actions-runner-controller/actions-runner-controller/blob/8b619e7c6fa9b8b07ff184e7882cec4108d0a52e/runner/actions-runner.dockerfile#L131-L132
Is PowerShell supposed to handle it, or do you need your own way?
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Hello @mumoshu
We are also quite new with Windows, but I'll try to answer here. As far as I know there are not termination signals on Windows, it is handled with the CRTL_SHUTDOWN_EVENT. On the kubernetes documentation I found this:
terminationGracePeriodSeconds - this is not fully implemented in Docker on Windows, see the GitHub issue. The behavior today is that the ENTRYPOINT process is sent CTRL_SHUTDOWN_EVENT, then Windows waits 5 seconds by default, and finally shuts down all processes using the normal Windows shutdown behavior. The 5 second default is actually in the Windows registry inside the container, so it can be overridden when the container is built.
I've found also this interesting article explaining windows shutdown process:
https://technoresult.com/windows-shutdown-process-behind-the-scean/
Which also says that at some point all running processes are shutdown with a grace period of 5 seconds with the same signal, the timeout for this is configurable as well.
As you know, on Linux you can handle everything in a much easier way, but Windows is different. We can play with shutdown timeouts and implement some logic for handling the CTRL_SHUTDOWN_EVENT signal with our entrypoint, but I don't think it's worth it because we would have to send more signals to processes, which the windows shutting down process already does.
Let me know what you think
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@amaldonadomat Good to know and totally understood. Thank you so much for sharing your knowledge and thoughts!
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@ian-flores Thank you so much for your efforts and contribution ❤️ |
This PR documents the process we used @voltrondata to add Windows self-hosted runners to be managed by the
actions-runner-controller. It specifies changes that need to be made to thecert-managerand theactions-runner-controller. It also specifies how to deployRunnerDeployment's configured for Windows.