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
This makes logging more concise by changing logger names to something like `controllers.Runner` to `actions-runner-controller.runner` after the standard `controller-rutime.controller` and reducing redundant logs by removing unnecessary requeues. I have also tweaked log messages so that their style is more consistent, which will also help readability. Also, runnerreplicaset-controller lacked useful logs so I have enhanced it.
We occasionally encountered those errors while the underlying RunnerReplicaSet is being recreated/replaced on RunnerDeployment.Spec.Template update. It turned out to be due to that the RunnerDeployment controller was waiting for the runner pod becomes `Running`, intead of the new replacement runner to have registered to GitHub. This fixes that, by trying to Runner.Status.Phase to `Running` only after the runner in the runner pod appears to be registered.
A side-effect of this change is that runner controller would call more "ListRunners" GitHub Actions API. I've reviewed and improved the runner controller code and Runner CRD to make make the number of calls minimum. In most cases, ListRunners should be called only twice for each runner creation.
PercentageRunnerBusy seems to have regressed since #355 due to that RunnerDeployment.Spec.Selector is empty by default and the HRA controller was using that empty selector to query runners, which somehow returned 0 runners. This fixes that by using the newly added automatic `runner-deployment-name` label for the default runner label and the selector, which avoids querying with empty selector.
Ref https://github.com/summerwind/actions-runner-controller/issues/377#issuecomment-795200205
* 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
Enhances #57 to add support for organizational runners.
As GitHub Actions does not have an appropriate API for this, this is the spec you need:
```
apiVersion: actions.summerwind.dev/v1alpha1
kind: RunnerDeployment
metadata:
name: myrunners
spec:
minReplicas: 1
maxReplicas: 3
autoscaling:
metrics:
- type: TotalNumberOfQueuedAndProgressingWorkflowRuns
repositories:
# Assumes that you have `github.com/myorg/myrepo1` repo
- myrepo1
- myrepo2
template:
spec:
organization: myorg
```
It works by collecting "in_progress" and "queued" workflow runs for the repositories `myrepo1` and `myrepo2` to autoscale the number of replicas, assuming you have this organizational runner deployment only for those two repositories.
For example, if `myrepo1` had 1 `in_progress` and 2 `queued` workflow runs, and `myrepo2` had 4 `in_progress` and 8 `queued` workflow runs at the time of running the reconcilation loop on the runner deployment, it will scale replicas to 1 + 2 + 4 + 8 = 15.
Perhaps we might be better add a kind of "ratio" setting so that you can configure the controller to create e.g. 2x runners than demanded. But that's another story.
Ref #10
* feat: Repository-wide RunnerDeployment Autoscaling
This adds `maxReplicas` and `minReplicas` to the RunnerDeploymentSpec. If and only if both fields are set, the controller computes and sets desired `replicas` automatically depending on the demand.
The number of demanded runner replicas is computed by `queued workflow runs + in_progress workflow runs` for the repository. The support for organizational runners is not included.
Ref https://github.com/summerwind/actions-runner-controller/issues/10
Since the initial implementation of RunnerDeployment and until this change, any update to a runner deployment has been leaving old runner replicasets until the next resync interval. This fixes that, by continusouly retrying the reconcilation 10 seconds later to see if there are any old runner replicasets that can be removed.
In addition to that, the cleanup of old runner replicasets has been improved to be deferred until all the runners of the newest replica set to be available. This gives you hopefully zero or at less downtime updates of runner deployments.
Fixes#24
Removes an unnecessary condition from the deployment controller code. We assumed that the client would return a not-found error on an empty runnerset list it is clearly not the case.
Adds the initial version of RunnerDeployment that is intended to manage RunnerSets(#1), like Deployment manages ReplicaSets.
This is the initial version and therefore is bare bone. The only update strategy it supports is `Recreate`, which recreates the underlying RunnerSet when the runner template changes. I'd like to add `RollingUpdate` strategy once this is merged.
This depends on #1 so the diff contains that of #1, too. Please see only the latest commit for review.
Also see https://github.com/mumoshu/actions-runner-controller-ci/runs/471329823?check_suite_focus=true to confirm that `make tests` is passing after changes made in this commit.
Yusuke Kuoka
Hidetake Iwata
Hiroshi Muraoka
Yusuke Kuoka
Moto Ishizawa