Nikola JokicandCopilot App
ec793dfe9f
When the AutoscalingRunnerSet's runner spec changes, the EphemeralRunnerSet has to delete its idle and pending runners so they are rebuilt from the new spec. That was detected by hashing Spec.EphemeralRunnerSpec into the actions.github.com/integrity-hash annotation and comparing the annotation against a freshly computed hash. Replace it with a monotonic revision counter split across spec and status. The AutoscalingRunnerSet controller bumps Spec.ActionableRevision when it patches a new runner spec across; the EphemeralRunnerSet controller advances Status.AppliedActionableRevision only after the cleanup has actually succeeded. Because the applied marker lives in status and is written last, a controller that crashes part-way through the cleanup comes back with the applied revision still behind the spec revision and redoes the work, instead of skipping runners that are still running the old spec. The drift check uses apiequality.Semantic.DeepEqual rather than cmp.Equal or reflect.DeepEqual. Most PodSpec collection fields carry omitempty, so a template containing an explicitly empty value (`env: []`) is dropped when the EphemeralRunnerSet is written and reads back as nil. A strict comparison would report drift on every reconcile, bump the revision each time, and delete every idle and pending runner forever. helpers_drift_test.go pins that behaviour with a round-trip-through-JSON test. 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.