* feat: copy dotfiles from asset to service dir
* Fixed `UNITTEST` Condition
* Load `/etc/environment`
See https://github.com/actions/runner/issues/1703 for context on this change.
docs: various changes in preparation for 0.22.0 release
- Move RunnerSets to a more predominant location in the docs
- Clean up a few bits
- Highlight the deprecation and removal timeline for the `--once` flag
- Renamed ephemeral runners section to something more logical (persistent runners). Static runners were an option however the word static is awkward as it's sort of tied up with autoscaling and the `Runner` kind so Persistent was chosen instead.
- Update upgrade docs to use `replace` instead of `apply`
Fix runner{set,deployment} rollouts and static runner scaling
I was testing static runners as a preparation to cut the next release of ARC, v0.22.0, and found several problems that I thought worth being fixed.
In particular, this PR fixes static runners reliability issues in two means.
c4b24f8366 fixes the issue that ARC gives up retrying RemoveRunner calls too early, especially on static runners, that resulted in static runners to often get terminated prematurely while running jobs.
791634fb12 fixes the issue that ARC was unable to scale up any static runners when the corresponding desired replicas number in e.g. RunnerDeployment gets updated. It was caused by a bug in the mechanism that is intended to prevent ephemeral runners from being recreated in unwanted circumstances, mistakenly triggered also for static runners.
Since #1179, RunnerDeployment was not able to gracefully terminate old RunnerReplicaSet on update. c612e87 fixes that by changing RunnerDeployment to firstly scale old RunnerReplicaSet(s) down to zero and waits for sync, and set the deletion timestamp only after that. That way, RunnerDeployment can ensure that all the old RunnerReplicaSets that are being deleted are already scaled to zero passing the standard unregister-and-then-delete runner termination process.
It revealed a hidden bug in #1179 that sometimes the scale-to-zero-before-runnerreplicaset-termination does not work as intended. 4551309 fixes that, so that RunnerDeployment can actually terminate old RunnerReplicaSets gracefully.
#1179 was not working particularly for scale down of static (and perhaps long-running ephemeral) runners, which resulted in some runner pods are terminated before the requested unregistration processes complete, that triggered some in-progress workflow jobs to hang forever. This fixes an edge-case that resulted in a decreased desired replicas to trigger the failure, so that every runner is unregistered then terminated, as originally designed.
It turned out that #1179 broke static runners in a way it is no longer able to scale up at all when the desired replicas is updated.
This fixes that by correcting a certain short-circuit that is intended only for ephemeral runners to not mistakenly triggered for static runners.
The unregister timeout of 1 minute (no matter how long it is) can negatively impact availability of static runner constantly running workflow jobs, and ephemeral runner that runs a long-running job.
We deal with that by completely removing the unregistaration timeout, so that regarldess of the type of runner(static or ephemeral) it waits forever until it successfully to get unregistered before being terminated.
As it turned out to be the biggest release ever, I was afraid I might not be able to write a summary of changes that communicates well. Here is my attempt. Please review and leave any comments so that we can be more confident in this release. Thank you!
I found that #1179 was unable to finish rollout of an RunnerDeployment update(like runner env update). It was able to create a new RunnerReplicaSet with the desired spec, but unable to tear down the older ones. This fixes that.
Use --ephemeral by default
Every runner is now --ephemeral by default.
Note that this works by ARC setting the RUNNER_FEATURE_FLAG_EPHEMERAL envvar to true by default. Previously you had to explicitly set it to true otherwise the runner was passed --once which is known to various race conditions.
It's worth noting that the very confusing and related configuration, ephemeral: true, which creates --once runners instead of static(or persistent) runners had been the default since many months ago. So, this should be the only change needed to make every runner ephemeral without any explicit configuration.
You can still fall back to static(persistent) runners by setting ephemeral: false, and to --once runners by setting RUNNER_FEATURE_FLAG_EPHEMERAL to "false". But I don't think there're many reasons to do so.
Ref #1189
The version of `bradleyfalzon/ghinstallation` which is used to enable GitHub App authentication turned out to add an extra header `application/vnd.github.machine-man-preview+json` to every HTTP request. That revealed an edge-case in our HTTP cache layer `gregjones/httpcache` that results it to not serve responses from cache when it should.
There were two problems. One was that it does not support multi-valued header and it only looked for the first value for each header, and another is that it does not support any http.RoundTripper implementation that modifies HTTP request headers in a RoundTrip function call.
I fixed it in my fork of httpcache, which is hosted at https://github.com/actions-runner-controller/httpcache.
The relevant commits are:
- 70d975e77d
- 197a8a3546
This can be considered as a follow-up for #1127, which turned out to have enabled the cache only for the case that ARC uses PAT for authentication.
Since this fix, the cache is also enabled when ARC authenticates as a GitHub App.
