funman300
8ae432223a
Replaces the detached `setsid nohup … nsenter …` launch, which had no restart policy, no boot persistence and no supervisor-visible logs. Staging units are installed and proven; production units are TEMPLATES and are not installed. Three decisions, each measured rather than assumed: * `Wants=`, not `Requires=`, from host to Core. With `Requires`, stopping Core stopped the host AND a later Core start did not bring it back -- a routine Core restart would leave the client with no server. With `Wants` the host survives a Core outage, answers 503 core_unavailable, never falls back to Python, and resumes the moment Core returns with no intervention. Both halves tested. * Readiness is a bounded ExecStartPre TCP gate, because ordering proves nothing about readiness and Type=exec only proves the binary exec'd. Core binds its listener after migrations and content load, so "port open" is a real signal. The gate FAILS rather than blocking: a host that waits forever looks healthy while serving nobody. * The netns is resolved by container NAME every start. The container is restart=unless-stopped and its netns inode CHANGES on restart (measured: 4026539938 -> 4026540033), so a hardcoded pid is wrong by construction and anything left in the old namespace serves nobody. Proven equivalent to today's nsenter against a scratch container, never production's namespace. `systemd-analyze verify` caught two real defects before deployment: StartLimitIntervalSec/StartLimitBurst sat in [Service], where systemd 252 silently ignores them, so the crash-loop ceiling was not taking effect; and a Documentation URL containing %20 parsed as a specifier. Both fixed and the effective properties re-confirmed from the running units. Staging evidence: Core-first ordering, host refused when Core is absent or merely not listening, outage survival, automatic recovery, restart, graceful stop with no strays, boot simulated via multi-user.target, 3x SIGKILL contained at ~5s spacing, journald logs, and economy state byte-identical throughout (integrity ok, fk 0).
58 lines
2.4 KiB
Bash
Executable File
58 lines
2.4 KiB
Bash
Executable File
#!/bin/sh
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# Publish a Docker container's network namespace into /run/netns so systemd
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# units can enter it declaratively with NetworkNamespacePath=.
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#
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# WHY THIS EXISTS. Production Core and host must run inside the
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# `openfut-fut-backend` container's netns: that is where the published client
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# ports live and where the Python oracle answers on 127.0.0.1:8199. Today they
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# get there with `nsenter --net=/proc/<pid>/ns/net`, where <pid> is typed by
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# hand into a runbook.
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#
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# THE HAZARD THIS FIXES, MEASURED NOT ASSUMED. The container runs with
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# `restart=unless-stopped`. On a container restart its netns inode CHANGES
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# (observed 2026-08-22: net:[4026539938] -> net:[4026540033]). A hardcoded pid
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# is then simply wrong, and — worse — any process already inside the old
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# namespace keeps running in a namespace with no interfaces, silently serving
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# nobody. Resolving by container NAME at every start removes the hardcoded pid;
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# the companion watcher unit handles the already-running case by restarting the
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# stack when the container restarts.
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#
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# Idempotent: a stale bind mount is unmounted and re-made, so re-running after a
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# container restart is the fix, not a second problem.
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#
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# usage: openfut-netns-bind.sh <container-name> <netns-name>
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set -eu
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CONTAINER="${1:?container name}"
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NSNAME="${2:?netns name}"
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TARGET="/run/netns/${NSNAME}"
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CPID="$(docker inspect -f '{{.State.Pid}}' "$CONTAINER" 2>/dev/null || true)"
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if [ -z "$CPID" ] || [ "$CPID" = "0" ]; then
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echo "openfut-netns-bind: container '$CONTAINER' is not running (pid='$CPID')" >&2
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exit 1
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fi
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if [ ! -e "/proc/$CPID/ns/net" ]; then
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echo "openfut-netns-bind: /proc/$CPID/ns/net does not exist" >&2
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exit 1
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fi
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WANT="$(readlink "/proc/$CPID/ns/net")"
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mkdir -p /run/netns
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# Already published and already CURRENT? Then do nothing — re-mounting under a
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# live service would be gratuitous churn.
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if mountpoint -q "$TARGET" 2>/dev/null; then
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HAVE="ns:[$(stat -c %i "$TARGET" 2>/dev/null || echo 0)]"
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if [ "net:[$(stat -c %i "$TARGET" 2>/dev/null)]" = "$WANT" ]; then
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echo "openfut-netns-bind: $TARGET already current ($WANT)"
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exit 0
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fi
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echo "openfut-netns-bind: $TARGET is STALE ($HAVE, want $WANT) — refreshing"
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umount "$TARGET" || true
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fi
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[ -e "$TARGET" ] || touch "$TARGET"
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mount --bind "/proc/$CPID/ns/net" "$TARGET"
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echo "openfut-netns-bind: $TARGET -> $CONTAINER pid $CPID $WANT"
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