# Shared-server build safety

- Keep Coolify server concurrent builds at **1** (previously 2).
- Do not run manual Docker builds on the production VM alongside deployments.
  Validate locally first; then push once and let the webhook build finish.
- The Docker builder caps Next page-generation workers and Rayon/libuv pools at
  two. Node subprocesses have a 1536 MiB old-space ceiling. These are not a hard
  total-memory limit: Bun, native allocations, and separate processes add overhead.
- Build controls are restricted to the builder stage; application runtime is
  unchanged. The final image must pass the Sharp WebP smoke test.
- If memory pressure remains high, move builds to a separate builder rather than
  increasing concurrency or running more diagnostic builds on the live VM.

## Coolify recovery and build isolation (2026-09-11)

Docker 29.3.0 crashed with SIGSEGV in its embedded BuildKit mount/read-entrypoint
path during the `4bc48db` deployment. The VM did not reboot, and the application
containers were not OOM-killed. Restarting the existing Manyangles containers
restored service. The trace identifies the failing process, not a confirmed
upstream defect or hardware cause.

- `/etc/docker/daemon.json` now enables `live-restore`. It was validated and
  applied with `systemctl reload docker`, without restarting running containers.
  The prior configuration is backed up at
  `/etc/docker/daemon.json.before-manyangles-recovery-20260911`.
- Manyangles uses the named `manyangles-isolated` buildx builder with the
  `docker-container` driver and `moby/buildkit:v0.33.0`, instead of the builder
  embedded inside dockerd. Other applications' build selection is unchanged.
- The builder has a 3 GiB RAM limit, 4 GiB combined RAM/swap limit, two-CPU quota,
  and two BuildKit execution slots. Images automatically load into the local
  Docker image store. Its cache is stored in a dedicated Docker volume.
- Coolify's application-level custom Compose build command is:

  ```sh
  docker compose --parallel 1 --project-name nzuqxqw47tbt117lrpw3f8ch build --builder manyangles-isolated --pull
  ```

  Coolify injects the project directory, Compose file, and build environment.
  Builder metadata lives under `/root/.docker/buildx`, which Coolify mounts into
  its helper. Do not select this builder globally or prune its volume during builds.

Verify using `docker info` (Live Restore Enabled), `docker buildx inspect
manyangles-isolated` as root, container health, and the public
`https://ma.hadlock.tech/api/health/ready` endpoint. Live restore mitigates daemon
outages; it does not provide zero-downtime Compose rollouts or protect against VM
failure. Do not deliberately crash/restart the shared daemon to test it in production.

References: [live restore](https://docs.docker.com/engine/daemon/live-restore/),
[containerized builders](https://docs.docker.com/build/builders/drivers/docker-container/).