public_git
/
actions-runner-controller
mirror of https://github.com/actions-runner-controller/actions-runner-controller.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

Add new architecture diagram (#2598)

This commit is contained in:
Bassem Dghaidi 2023-05-17 14:36:16 +02:00 committed by GitHub
parent 7ab516fdab
commit 44e9b7d8eb
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 21 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
docs/preview/gha-runner-scale-set-controller/README.md
View File

@ -4,7 +4,20 @@ This new autoscaling mode brings numerous enhancements (described in the followi
## How it works
![arc_hld_v1 drawio (1)](https://user-images.githubusercontent.com/568794/212665433-2d1f3d6e-0ba8-4f02-9d1b-27d00c49abd1.png)
![ARC architecture diagram](arc-diagram-light.png#gh-light-mode-only)
![ARC architecture diagram](arc-diagram-dark.png#gh-dark-mode-only)
1. ARC is installed using the supplied Helm charts, and the controller manager pod is deployed in the specified namespace. A new `AutoScalingRunnerSet` resource is deployed via the supplied Helm charts or a customized manifest file. The `AutoScalingRunnerSet` controller calls GitHub's APIs to fetch the runner group ID that the runner scale set will belong to.
2. The `AutoScalingRunnerSet` controller calls the APIs one more time to either fetch or create a runner scale set in the `Actions Service` before creating the `Runner ScaleSet Listener` resource.
3. A `Runner ScaleSet Listener` pod is deployed by the `AutoScaling Listener Controller`. In this pod, the listener application connects to the `Actions Service` to authenticate and establish a long poll HTTPS connection. The listener stays idle until it receives a `Job Available` message from the `Actions Service`.
4. When a workflow run is triggered from a repository, the `Actions Service` dispatches individual job runs to the runners or runner scalesets where the `runs-on` property matches the name of the runner scaleset or labels of self-hosted runners.
5. When the `Runner ScaleSet Listener` receives the `Job Available` message, it checks whether it can scale up to the desired count. If it can, the `Runner ScaleSet Listener` acknowledges the message.
6. The `Runner ScaleSet Listener` uses a `Service Account` and a `Role` bound to that account to make an HTTPS call through the Kubernetes APIs to patch the `EphemeralRunner Set` resource with the number of desired replicas count.
7. The `EphemeralRunner Set` attempts to create new runners and the `EphemeralRunner Controller` requests a JIT configuration token to register these runners. The controller attempts to create runner pods. If the pod's status is `failed`, the controller retries up to 5 times. After 24 hours the `Actions Service` unassigns the job if no runner accepts it.
8. Once the runner pod is created, the runner application in the pod uses the JIT configuration token to register itself with the `Actions Service`. It then establishes another HTTPS long poll connection to receive the job details it needs to execute.
9. The `Actions Service` acknowledges the runner registration and dispatches the job run details.
10. Throughout the job run execution, the runner continuously communicates the logs and job run status back to the `Actions Service`.
11. When the runner completes its job successfully, the `EphemeralRunner Controller` checks with the `Actions Service` to see if runner can be deleted. If it can, the `Ephemeral RunnerSet` deletes the runner.
In addition to the increased reliability of the automatic scaling, we have worked on these improvements:
@ -16,7 +29,7 @@ In addition to the increased reliability of the automatic scaling, we have worke
### Demo
[![Watch the walkthrough](./thumbnail.png)](https://youtu.be/wQ0k5k6KW5Y)
[![Watch the walkthrough](thumbnail.png)](https://youtu.be/wQ0k5k6KW5Y)
> Will take you to Youtube for a short walkthrough of the Autoscaling Runner Scale Sets mode.

3
docs/preview/gha-runner-scale-set-controller/arc-diagram-dark.png Normal file
View File

@ -0,0 +1,3 @@
version https://git-lfs.github.com/spec/v1
oid sha256:5eb13eaa0f0495f4f742a968072f5086f9eae4f8e2204e5b5c4a6c3ffabdf39a
size 1212398

3
docs/preview/gha-runner-scale-set-controller/arc-diagram-light.png Normal file
View File

@ -0,0 +1,3 @@
version https://git-lfs.github.com/spec/v1
oid sha256:bbae2b58eb5636348560d9c4b3a06a92ed60a30276fc9f2ff452c37ce961b40a
size 801347