Update about-support-for-actions-runner-controller.md (#56017)

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Sunbrye Ly <56200261+sunbrye@users.noreply.github.com>
Co-authored-by: sunbrye <sunbrye@github.com>

content/actions/hosting-your-own-runners/managing-self-hosted-runners-with-actions-runner-controller/about-support-for-actions-runner-controller.md

@@ -39,12 +39,10 @@ While ARC may be deployed successfully with different tooling and configurations
 * Installation tooling other than Helm
 * Service account and/or template spec customization
 
-If you're uncertain if the issue is out of scope, open a ticket and we're happy to help you determine the best way to proceed.
-
 For more information about contacting {% data variables.contact.github_support %}, see [AUTOTITLE](/support/contacting-github-support).
 
 > [!NOTE]
-> * OpenShift clusters are currently unsupported.
+> * OpenShift clusters are in public preview. See guidance from [Red Hat](https://developers.redhat.com/articles/2025/02/17/how-securely-deploy-github-arc-openshift#arc_architecture) for configuration recommendations.
 > * ARC is only supported on GitHub Enterprise Server versions 3.9 and greater.
 
 ## Working with {% data variables.contact.github_support %} for Actions Runner Controller

content/actions/hosting-your-own-runners/managing-self-hosted-runners-with-actions-runner-controller/authenticating-to-the-github-api.md

@@ -85,6 +85,108 @@ ARC can use {% data variables.product.pat_v1_plural %} to register self-hosted r
 
    {% data reusables.actions.actions-runner-controller-helm-chart-options %}
 
+## Authenticating ARC with vault secrets
+
+> [!NOTE]
+> Vault integration is currently available in public preview with support for Azure Key Vault.
+
+Starting with gha-runner-scale-set version 0.12.0, ARC supports retrieving GitHub credentials from an external vault. Vault integration is configured per runner scale set. This means you can run some scale sets using Kubernetes secrets while others use vault-based secrets, depending on your security and operational requirements.
+
+### Enabling Vault Integration
+
+To enable vault integration for a runner scale set:
+
+1. **Set the `githubConfigSecret` field** in your `values.yaml` file to the name of the secret key stored in your vault. This value must be a string.
+1. **Uncomment and configure the `keyVault` section** in your `values.yaml` file with the appropriate provider and access details.
+1. **Provide the required certificate** (`.pfx`) to both the controller and the listener. You can do this by:
+   *Rebuilding the controller image with the certificate included, or
+   *Mounting the certificate as a volume in both the controller and the listener using the `listenerTemplate` and `controllerManager` fields.
+
+### Secret Format
+
+The secret stored in Azure Key Vault must be in JSON format. The structure depends on the type of authentication you are using:
+
+#### Example: GitHub Token
+
+```json
+{
+  "github_token": "TOKEN"
+}
+```
+
+#### Example: GitHub App
+
+```json
+{
+  "github_app_id": "APP_ID_OR_CLIENT_ID",
+  "github_app_installation_id": "INSTALLATION_ID",
+  "github_app_private_key": "PRIVATE_KEY"
+}
+```
+
+### Configuring `values.yaml` for Vault Integration
+
+The certificate is stored as a .pfx file and mounted to the container at /akv/cert.pfx. Below is an example of how to configure the keyVault section to use this certificate for authentication:
+
+```yaml
+keyVault:
+  type: "azure_key_vault"
+  proxy:
+    https:
+      url: "PROXY_URL"
+      credentialSecretRef: "PROXY_CREDENTIALS_SECRET_NAME"
+    http: {}
+    noProxy: []
+  azureKeyVault:
+    clientId: <AZURE_CLIENT_ID>
+    tenantId: <AZURE_TENANT_ID>
+    url: <AZURE_VAULT_URL>
+    certificatePath: "/akv/cert.pfx"
+```
+
+### Providing the Certificate to the Controller and Listener
+
+ARC requires a `.pfx` certificate to authenticate with the vault. This certificate must be made available to both the controller and the listener components during controller installation.
+You can do this by mounting the certificate as a volume using the `controllerManager` and `listenerTemplate` fields in your `values.yaml` file:
+
+```yaml
+volumes:
+  - name: cert-volume
+    secret:
+      secretName: my-cert-secret
+volumeMounts:
+  - mountPath: /akv
+    name: cert-volume
+    readOnly: true
+
+listenerTemplate:
+  volumeMounts:
+    - name: cert-volume
+      mountPath: /akv/certs
+      readOnly: true
+  volumes:
+    - name: cert-volume
+      secret:
+        secretName: my-cert-secret
+```
+
+The code below is an example of a scale set `values.yml` file.
+
+```yaml
+listenerTemplate:
+  spec:
+    containers:
+      - name: listener
+        volumeMounts:
+          - name: cert-volume
+            mountPath: /akv
+            readOnly: true
+    volumes:
+      - name: cert-volume
+        secret:
+          secretName: my-cert-secret
+```
+
 ## Legal notice
 
 {% data reusables.actions.actions-runner-controller-legal-notice %}