From e512922f9b6136858c7d80ade8b4f61baae35c85 Mon Sep 17 00:00:00 2001 From: "github-actions[bot]" <41898282+github-actions[bot]@users.noreply.github.com> Date: Tue, 12 May 2026 11:29:48 +0000 Subject: [PATCH] docs: document ARC/DinD auto-detection for AWF docker-host-path-prefix Document the runtime probe added in #31614 that detects ARC with Docker-in-Docker sidecar topology via DOCKER_HOST and appends --docker-host-path-prefix /tmp/gh-aw to AWF invocations. Co-Authored-By: Claude Opus 4.7 (1M context) --- docs/src/content/docs/guides/self-hosted-runners.md | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/docs/src/content/docs/guides/self-hosted-runners.md b/docs/src/content/docs/guides/self-hosted-runners.md index 4bd193e453a..cff42c89f8f 100644 --- a/docs/src/content/docs/guides/self-hosted-runners.md +++ b/docs/src/content/docs/guides/self-hosted-runners.md @@ -16,6 +16,14 @@ Use the `runs-on` frontmatter field to target a self-hosted runner instead of th > For these reasons, a non-sudo mode is not supported, including ARC configurations with `allowPrivilegeEscalation: false`. +## ARC with Docker-in-Docker (DinD) + +Actions Runner Controller (ARC) deployments that use a Docker-in-Docker sidecar split the runner container and the Docker daemon container across separate filesystems, so bind mounts constructed from the runner's perspective fail inside the daemon. + +`gh aw compile` emits a runtime probe in generated workflows that inspects `DOCKER_HOST` and appends `--docker-host-path-prefix /tmp/gh-aw` to the AWF invocation when the value matches `tcp://localhost:` or `tcp://127.0.0.1:`. No workflow-level configuration is required. + +The probe is gated on AWF `v0.25.43` or newer. Workflows pinned to an older AWF version, or running on GitHub-hosted runners (where `DOCKER_HOST` is unset or points at a Unix socket), are unaffected. + ## runs-on formats **String** — single runner label: