An EphemeralRunnerSet goes Outdated when a child runner reports that the
Actions service rejected its runner spec, and the AutoscalingRunnerSet
then tears the listener down so the scale set stops taking jobs. Until
now nothing recorded which runner spec a given Outdated report was about,
so a report from a runner that predates a spec update kept the set
switched off even after the user had already fixed the spec.
Runners now carry the EphemeralRunnerSet's actionable revision as an
annotation, and Outdated runners are split into two groups:
- stale outdated: created before the currently applied revision. Their
verdict is about a spec that no longer exists, so they are deleted
and replaced by runners built from the current spec.
- outdated: created at or after the applied revision. Their verdict is
about the current spec, so they hold the set in the Outdated phase.
They are deliberately not delete-and-replaced: a fresh runner at the
same revision would report Outdated again, forever.
patchAppliedActionableRevisionStatus now recomputes the phase in both
directions against the revision being applied, because it returns from
Reconcile without reaching updateStatus. The AutoscalingRunnerSet
teardown guard additionally requires the applied revision to have caught
up with the spec revision, so it does not act on an Outdated verdict for
a spec that has already been replaced.
terminated() now allocates a fresh slice instead of appending into the
finished slice, which could alias its backing array.
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Actions Runner Controller (ARC)
About
Actions Runner Controller (ARC) is a Kubernetes operator that orchestrates and scales self-hosted runners for GitHub Actions.
With ARC, you can create runner scale sets that automatically scale based on the number of workflows running in your repository, organization, or enterprise. Because controlled runners can be ephemeral and based on containers, new runner instances can scale up or down rapidly and cleanly. For more information about autoscaling, see "Autoscaling with self-hosted runners."
You can set up ARC on Kubernetes using Helm, then create and run a workflow that uses runner scale sets. For more information about runner scale sets, see "Deploying runner scale sets with Actions Runner Controller."
People
Actions Runner Controller (ARC) is an open-source project currently developed and maintained in collaboration with the GitHub Actions team, external maintainers @mumoshu and @toast-gear, various contributors, and the awesome community.
If you think the project is awesome and is adding value to your business, please consider directly sponsoring community maintainers and individual contributors via GitHub Sponsors.
If you are already the employer of one of the contributors, sponsoring via GitHub Sponsors might not be an option. Just support them by other means!
See the sponsorship dashboard for the former and the current sponsors.
Getting Started
To give ARC a try with just a handful of commands, please refer to the Quickstart guide.
For an overview of ARC, please refer to About ARC.
With the introduction of autoscaling runner scale sets, the existing autoscaling modes are now legacy. The legacy modes have certain use cases and will continue to be maintained by the community only.
For further information on what is supported by GitHub and what's managed by the community, please refer to this announcement discussion.
Documentation
ARC documentation is available on docs.github.com.
Legacy documentation
The following documentation is for the legacy autoscaling modes that continue to be maintained by the community:
- Quickstart guide
- About ARC
- Installing ARC
- Authenticating to the GitHub API
- Deploying ARC runners
- Adding ARC runners to a repository, organization, or enterprise
- Automatically scaling runners
- Using custom volumes
- Using ARC runners in a workflow
- Managing access with runner groups
- Configuring Windows runners
- Using ARC across organizations
- Using entrypoint features
- Deploying alternative runners
- Monitoring and troubleshooting
Contributing
We welcome contributions from the community. For more details on contributing to the project (including requirements), please refer to "Getting Started with Contributing."
Troubleshooting
We are very happy to help you with any issues you have. Please refer to the "Troubleshooting" section for common issues.