Run a duplicate of CI on the new ARC (Actions Runner Controller) runners in
GKE, beside the existing CI. The duplicate does not change production CI.
Every workflow in .github/workflows/ that does not start with newci- is
byte-identical to main. Watch the shadow runs for a few days, then migrate.
The shadow set is 16 files: newci-ci.yml plus the 15 reusable workflows that
ci.yml calls on a pull request. Only pull-request workflows are copied.
js-autofix, deploy-site, and skills-index run on push or on a schedule. A
copy of those would push branches and deploy the site a second time.
Safety properties of the shadow:
- Concurrency groups are newci-prefixed. This is the important one. The
production groups use cancel-in-progress, so a shared group would let a
shadow run cancel the production run.
- Cache keys are newci-prefixed. The shadow cannot poison or evict a
production cache entry.
- Reusable-workflow calls point only at other newci-* files. No shadow job
calls a production workflow.
- The PR review comment runs with --dry-run. It prints the comment body to
the job log. Two pollers cannot fight over the hermes-ci-review-bot
comment.
- The gate job is renamed to "[newci] All checks pass (informational)". The
production check "All required checks pass" stays the only merge gate.
- The shadow runs on pull_request only. The push trigger is removed.
- docker publish and merge jobs are unreachable. Their conditions require a
push to main or a release.
Runner infrastructure, in the shadow copies only:
- Jobs go to three scale sets: arc-runner-small for short gate jobs,
arc-runner-set for general work, arc-runner-docker and arc-runner-arm64
for image builds. dind is only on the docker sets, so the other jobs stop
paying for a privileged sidecar.
- The runner image supplies node 26, npm 12, uv, Python, and ripgrep. The
setup-node, setup-uv, and per-job install steps are gone.
- Checkout uses a node-local git mirror, seeded from the runner pod env.
- buildx layer cache moved to Artifact Registry in us-central1, the same
region as the runners. Reads are keyless through GKE Workload Identity.
Writes use GitHub OIDC and happen only on main pushes and releases, so
pull-request code cannot write a layer that the publish job reads.
Merge-base work, in the shadow copies only:
- A new composite action, .github/actions/merge-base, deepens a shallow
clone until the two histories connect. fetch-depth: 0 fetches all ~1400
refs and measured 76-81s, against 3-6s for a shallow checkout.
- The action fails by default when no merge base exists. A three-dot diff
over a missing merge base scans nothing and reports clean, so the
supply-chain audit must stop. history-check sets fail-on-missing to false,
because absence is the result it measures.
- lint diffs against the base commit directly. The job checks out the PR
merge ref, so base.sha is already the correct comparison point.
- contributor-check uses origin/main..HEAD. The result equals the merge-base
form, and the extra git call also expanded a SHA without quotes.
Other changes:
- .github/actionlint.yaml declares the four ARC labels. actionlint knows
only GitHub-hosted labels, so every runs-on in the repo was reported as an
unknown label: 40 warnings that hid real findings.
- scripts/ci/resource_profile.py records CPU and memory for a job step. The
timing report shows the data per step.
- run_tests_parallel.py can list test files from the git index. The slice
generator then needs no blobs.
- Docker test files are split so boot-heavy tests run in parallel.
- Container-environment parity fixes in doctor, gateway, and skill_utils,
with tests.
To retire the shadow: delete .github/workflows/newci-*.yml.
PR #30136 review surfaced two issues, both rooted in the same audit gap:
docker integration tests were running as root, not the unprivileged
`hermes` user (UID 10000) that the runtime actually uses via
`s6-setuidgid hermes`. Anything that probed PID-1 state or wrote to
the s6 control surface worked as root in the tests but was inert in
production.
Fixes:
1. `_s6_running()` previously called `Path("/proc/1/exe").resolve()`,
which is root-only readable. For UID 10000 the symlink yields
PermissionError, `resolve()` silently returns the unresolved path,
and `exe.name == "exe"` — so detection always returned False, the
service-manager runtime-registration path was inert, and every
`hermes profile create` / `hermes -p X gateway start` silently
skipped the s6 hook. Replace with `/proc/1/comm` (world-readable)
+ `/run/s6/basedir` (s6-overlay-specific) — both required, fail
closed.
2. `02-reconcile-profiles` now also chowns `/run/service/.s6-svscan/`
{control,lock} to hermes so `s6-svscanctl -a/-an` works without
root. Previously the directory chown stopped at `/run/service`
and the FIFO inside stayed root-owned, so `register_profile_gateway`
from hermes failed at the rescan-trigger step with EACCES — the
wrapper in profiles.py caught the exception and printed a swallowed
warning, so profile creation appeared to succeed while the slot
was rolled back.
Audit changes to flush this class of bug next time:
- Add `docker_exec` / `docker_exec_sh` helpers to `tests/docker/conftest.py`
that default to `-u hermes`. The module docstring explains why and
flags `user="root"` as opt-in only for tests that explicitly need
root (none currently do).
- Refactor every `docker exec` call in tests/docker/ through the new
helpers (test_dashboard.py, test_zombie_reaping.py, test_profile_gateway.py,
test_container_restart.py, test_s6_profile_gateway_integration.py).
- Add 5 unit tests covering `_s6_running` under various probe states
(both signals present; comm wrong; basedir missing; PermissionError
on /proc/1/comm; missing /proc — non-Linux). The PermissionError
test is the explicit regression guard for the original bug.
Known follow-up: the per-service `supervise/control` FIFO inside each
`/run/service/gateway-<profile>/supervise/` is created root-owned by
s6-supervise (which runs as root because s6-svscan is PID 1). `s6-svc
-u/-d/-t` from the hermes user will get EACCES on those. The audit
under `-u hermes` will reveal this in lifecycle tests — surfacing the
issue cleanly so it can be fixed in a focused follow-up (likely via a
small SUID helper or a polling chown loop in cont-init.d). The
detection + svscanctl fixes here are independent and complete on
their own.
The agent-test suite default is 30s; docker test_no_args (the dashboard
spin-up, the container restart) routinely take 60-90s. Without this
they intermittently fail in CI with TimeoutError.
Task 0.1 of the s6-overlay supervision plan. Establishes the test
infrastructure for tests/docker/: skip-on-missing-Docker collection
hook, session-scoped image-build fixture (overridable via the
HERMES_TEST_IMAGE env var for faster local iteration), and a
container_name fixture that ensures cleanup on test exit.
Refs: docs/plans/2026-05-07-s6-overlay-dynamic-subagent-gateways.md
ethernet
Ben