This is an attempt to support scaling from/to zero.
The basic idea is that we create a one-off "registration-only" runner pod on RunnerReplicaSet being scaled to zero, so that there is one "offline" runner, which enables GitHub Actions to queue jobs instead of discarding those.
GitHub Actions seems to immediately throw away the new job when there are no runners at all. Generally, having runners of any status, `busy`, `idle`, or `offline` would prevent GitHub actions from failing jobs. But retaining `busy` or `idle` runners means that we need to keep runner pods running, which conflicts with our desired to scale to/from zero, hence we retain `offline` runners.
In this change, I enhanced the runnerreplicaset controller to create a registration-only runner on very beginning of its reconciliation logic, only when a runnerreplicaset is scaled to zero. The runner controller creates the registration-only runner pod, waits for it to become "offline", and then removes the runner pod. The runner on GitHub stays `offline`, until the runner resource on K8s is deleted. As we remove the registration-only runner pod as soon as it registers, this doesn't block cluster-autoscaler.
Related to #447
We sometimes see that integration test fails due to runner replicas not meeting the expected number in a timely manner. After investigating a bit, this turned out to be due to that HRA updates on webhook-based autoscaler and HRA controller are conflicting. This changes the controllers to use Patch instead of Update to make conflicts less likely to happen.
I have also updated the hra controller to use Patch when updating RunnerDeployment, too.
Overall, these changes should make the webhook-based autoscaling more reliable due to less conflicts.
`kubectl get horizontalrunnerautoscalers.actions.summerwind.dev` shows HRA.status.desiredReplicas as the DESIRED count. However the value had been not taking capacityReservations into account, which resulted in showing incorrect count when you used webhook-based autoscaler, or capacityReservations API directly. This fixes that.
I have heard from some user that they have hundred thousands of `status=completed` workflow runs in their repository which effectively blocked TotalNumberOfQueuedAndInProgressWorkflowRuns from working because of GitHub API rate limit due to excessive paginated requests.
This fixes that by separating list-workflow-runs calls to two - one for `queued` and one for `in_progress`, which can make the minimum API call from 1 to 2, but allows it to work regardless of number of remaining `completed` workflow runs.
* feat: HorizontalRunnerAutoscaler Webhook server
This introduces a Webhook server that responds GitHub `check_run`, `pull_request`, and `push` events by scaling up matched HorizontalRunnerAutoscaler by 1 replica. This allows you to immediately add "resource slack" for future GitHub Actions job runs, without waiting next sync period to add insufficient runners.
This feature is highly inspired by https://github.com/philips-labs/terraform-aws-github-runner. terraform-aws-github-runner can manage one set of runners per deployment, where actions-runner-controller with this feature can manage as many sets of runners as you declare with HorizontalRunnerAutoscaler and RunnerDeployment pairs.
On each GitHub event received, the webhook server queries repository-wide and organizational runners from the cluster and searches for the single target to scale up. The webhook server tries to match HorizontalRunnerAutoscaler.Spec.ScaleUpTriggers[].GitHubEvent.[CheckRun|Push|PullRequest] against the event and if it finds only one HRA, it is the scale target. If none or two or more targets are found for repository-wide runners, it does the same on organizational runners.
Changes:
* Fix integration test
* Update manifests
* chart: Add support for github webhook server
* dockerfile: Include github-webhook-server binary
* Do not import unversioned go-github
* Update README
* Adds RUNNER_GROUP argument to the runner registration
Adds the ability to register a runner to a predefined runner_group
Resolves#137
* Update README with runner group example
- Updates the README with instructions of how to add the runner to a
group
- Fix code fencing for shell and yaml blocks in the README
- Use consistent bullet points (dash not asterisk)
Currently, after refreshing the token, the controller re-creates the runner with the new token. This results in jobs being interrupted. This PR makes sure the pod is not restarted if it is busy.
Closes#74
This is a follow-up for #66.
The reconciler for the new HorizontalRunnerDeploymentAutoscaler had a terrible flaw that prevented the controller to fail launching due to an error like:
```
indexer conflict: map[field:.metadata.controller:{}]
```
This fixes that, while adding `integration_test.go` to verify its actually fixed and prevent regression in the future.
Yusuke Kuoka
Hiroshi Muraoka
Hidetake Iwata
Dan Webb
Helder Moreira
Yusuke Kuoka