Files
OpenFUT/scripts/systemd/openfut-staging-host.service
T
funman300 1e8d46b258 ops(systemd): follow the anchor container's netns across recreation
Recreating the Docker anchor left the supervised Core and host stranded in
the dead namespace while systemd still reported them active — serving
nobody, invisible to any monitoring that trusts unit state. Reproduced on
staging: netns 4026539938 -> 4026540033, both pids unchanged in the old
one, both units "active", traffic ConnectionResetError.

There is no systemd-native edge signal to bind to. Containers do appear as
units, but the scope name embeds the container ID (docker-<id>.scope), which
changes on every recreate, so BindsTo= has no stable target;
NetworkNamespacePath= resolves once at start; a .path unit on /run/netns
would watch the file this tooling maintains. So: a level-triggered reconcile
on a 10s timer, comparing the namespace the services are ACTUALLY in against
the anchor's CURRENT one, acting only on a real difference. That cannot miss
an event while the watcher restarts or dockerd is down, and needs no
debounce — a burst of three recreations produced exactly one rebind. The
trigger stays separable: a docker-events unit could invoke the same script.

Anchor absent stops the dependants rather than falling back to host
networking; docker unavailable logs once and retries on the next tick.

Two defects found while testing and fixed here:
- mount --bind STACKS when the old mount is busy, silently leaking nsfs
  entries; the bind helper now drains stale mounts in a loop.
- reconcile must stop -> rebind -> start, not rebind -> restart: a running
  service holds the old namespace open and makes the umount fail busy.

Staging also gained a faithful anchor container so the reproduction is
structural rather than mocked. Economy state was byte-identical across every
lifecycle test. Production units are templates only and remain uninstalled.
2026-08-22 21:14:23 +00:00

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[Unit]
Description=OpenFUT FIFA17 UTAS host (STAGING) — client-facing, Core-dependent
Documentation=file:///home/alex/OpenFUT/scripts/systemd/README.md
# ORDERING AND ADMISSION. `Wants` + `After` order the host after Core and pull
# Core in when the host is started; neither gives READINESS, because Type=exec
# only proves the binary exec'd. The ExecStartPre below is what actually admits
# traffic: the host cannot reach "active" while Core is not listening.
Wants=openfut-staging-core.service
After=openfut-staging-core.service
# Requires on the NAMESPACE (hard) but only Wants on Core (soft) — the host
# must never bind the host network, yet must survive a Core blip.
Requires=openfut-staging-netns.service
After=openfut-staging-netns.service
# `Wants`, deliberately NOT `Requires`/`BindsTo`/`PartOf`. Those propagate a
# Core stop into a host stop, and — measured, not assumed — a later Core start
# does NOT bring the host back, so a routine Core restart would silently leave
# the client with no server at all.
#
# With `Wants` the host survives a Core outage and answers 503
# `core_unavailable`, never falling back to Python. That is the behaviour
# production already exhibited on 2026-08-22 when Core was SIGHUP'd out from
# under a live host. Because the host holds no Core state between requests, it
# resumes serving the moment Core returns, with no supervisor intervention.
# StartLimit* MUST live in [Unit]: systemd 252 silently IGNORES them in
# [Service] (`systemd-analyze verify` flags it), which would have left the
# crash-loop ceiling at the 10s/5 default instead of the intended 60s window.
StartLimitIntervalSec=60
StartLimitBurst=5
[Service]
Type=exec
User=alex
Group=alex
WorkingDirectory=/home/alex/openfut-sold-staging
NetworkNamespacePath=/run/netns/openfut-staging
EnvironmentFile=/home/alex/openfut-sold-staging/systemd/host.env
# Readiness gate. Bounded, and FAILS rather than blocking forever: a host that
# waits indefinitely looks healthy to the supervisor while serving nothing.
ExecStartPre=/home/alex/OpenFUT/scripts/systemd/openfut-wait-tcp.sh 127.0.0.1 18081 30
ExecStart=/home/alex/openfut-sold-staging/bin/openfut-utas-host
KillSignal=SIGTERM
KillMode=mixed
TimeoutStopSec=20
Restart=on-failure
RestartSec=5s
StandardOutput=journal
StandardError=journal
SyslogIdentifier=openfut-staging-host
[Install]
WantedBy=multi-user.target