Enhance ARC runner image dockerfiles for RunnerScaleSet compatibility

[mumoshu]

Hi! I made our current runner images work with the new RunnerScaleSet.

Let me share how so everyone can try and figure out how to build custom runner images that contain more tools and software you like 👋

I'm submitting this as a pull request because it doesn't break our current runner images and is worth merging for a better experience migrating to the new ARC!

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There are only a few differences between the new and the current runner images.

TL;DR; We can add some dockerfile build args and envs and make the part that calls config.sh to be conditional and that's all you need to make it work with RunnerScaleSet.

Here are the differences:

	Current	New
Images	https://hub.docker.com/r/summerwind/actions-runner, https://github.com/orgs/actions-runner-controller/packages	https://github.com/actions/runner/pkgs/container/actions-runner
Dockerfiles	https://github.com/actions/actions-runner-controller/tree/master/runner	https://github.com/actions/runner/tree/main/images
$HOME	/runner	/home/runner
Location of source "externals" dir	/runner/externalstmp	/home/runner/externals
How you copy externals for dind sidecar	startup.sh within runner container runs cp	Init container runs cp
Token registration	Controller creates a registration token and config.sh within runner obtains another token for actions/runner	Controller obtains the token and runner uses it as-is, without config.sh

And apparently, the changes introduced via this pull request is all you need to make it work for both.

You can build e.g., an Ubuntu 20.04 runner image that seems to work with the new RunnerScaleSet by overriding some paths via new build args added in this PR:

# Whatever version you want to use for this
DOCKER_REPO=yourcontainerregistry/arc-runner-temp-v1-ubuntu-20.04
VER=0.1
docker build \
  --build-arg RUNNER_ASSETS_DIR=/home/runner \
  --build-arg TARGETPLATFORM=linux/amd64 \
  --build-arg RUNNER_VERSION=2.304.0 \
  --build-arg EXTERNALS_DIR_NAME=externals \
  -t $DOCKER_REPO:$VER \
  -f runner/actions-runner.ubuntu-20.04.dockerfile \
  runner
# Add `--load ` or `--push` if you're using buildx!

[Link-]

Awesome work as usual @mumoshu ! Do you want me to test this or you're confident with your tests?

[int128]

JFY: I tested this pull request as https://github.com/int128/actions-runner-controller-in-actions/pull/6. I'm not sure but found the following issues:

• actions-runner image works perfectly 👍
• actions-runner-dind image:
  • Runner works but dockerd seems not running.
  • I set the entrypoint to /home/runner/run.sh but different one is required?
• actions-runner-dind-rootless image:
  • actions/checkout did not work due to this error: An error occurred trying to start process '/home/runner/externals/node16/bin/node' with working directory '/home/runner/_work/actions-runner-controller-in-actions/actions-runner-controller-in-actions'. No such file or directory

[int128]

I hope this would be an official image for RunnerScaleSets.

We tried ghcr.io/actions/runner image in our organization, but some actions such as ruby/setup-ruby did not work since that image is Debian based.

[Link-]

Switch from Debian to Ubuntu 22.04 https://github.com/actions/runner/pull/2651

[apr-1985]

Hello. Is this going to get in? I like that this image comes with most required software included, makes it more closely aligned to using the GHA Cloud Runners.

[Link-]

Pending testing

[rs1986x]

I really like both old and new setups, but in the new setup I do miss the option to run dind in a single image and be able to set precise requests and limits for the whole thing.