Build and push runner images / build-runners (pull_request) Failing after 40s
ROOT CAUSE: Docker socket (/var/run/docker.sock) only existed inside the dind container — the runner container couldn't see it. The runner connected to dind via TCP (tcp://localhost:2376) with TLS. But workflow containers created by the runner had NO way to access the docker daemon: - unix socket not mounted (runner can't see it) - DOCKER_HOST env var not passed (runner.envs not configured) FIX: Share /var/run between dind and runner via emptyDir volume. When dind starts, it creates /var/run/docker.sock in the shared volume. Runner can now see the socket. docker_host: automount in config tells the runner to mount the socket into job containers automatically. Architecture after fix: dind container → creates /var/run/docker.sock → shared emptyDir runner container → sees /var/run/docker.sock → uses automount workflow container → gets /var/run/docker.sock mounted by runner Also removed runner.envs (TCP+TLS approach) — unix socket is simpler and works with automount.