ff6ce7b091
Symmetric with the earlier mount cleanup (commits 519567e..a982995). Until now, the unit's ExecStartPre handled mount but the Python side still drove unmount: stop_instance and _purge_instance both called _mounter.unmount, which wrapped sudo + the helper. Two code paths for two halves of the same lifecycle. Move unmount into the unit: - ExecStopPost=+/usr/local/libexec/left4me/left4me-overlay umount %i (ExecStopPost, not ExecStop, so it runs after the cgroup is cleared; ExecStop runs while srcds is alive and would EBUSY the umount syscall.) - Helper's umount verb is now idempotent (mirrors mount): if merged isn't a mount point, return early. PRINT_ONLY mode bypasses both short-circuits so the unit tests still exercise the full nsenter argv. Drop the dead Python machinery: - _mounter.unmount(...) calls in stop_instance and _purge_instance - _mounter global + KernelOverlayFSMounter import - The whole l4d2host/fs/ package (OverlayMounter ABC + KernelOverlayFSMounter class) — no production callers, just self-tests - l4d2host/tests/test_kernel_overlayfs.py - test_stop_succeeds_when_unmount_fails / test_delete_succeeds_when_unmount_fails (tested Python-side unmount-failure tolerance that no longer exists) - The l4d2host.fs.kernel_overlayfs.run_command monkeypatches in lifecycle tests After this, the only thing start_instance does beyond cfg-staging is ask systemd to enable+start the unit. stop/delete/reset only ask systemd to disable; the overlay lifecycle lives entirely in the unit file. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
67 lines
2.6 KiB
Desktop File
67 lines
2.6 KiB
Desktop File
[Unit]
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Description=left4me server instance %i
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After=network-online.target
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Wants=network-online.target
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# Bound the restart loop. Without these, a persistent ExecStartPre or
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# ExecStart failure spins indefinitely. Note: these are [Unit]-section
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# directives (systemd 230+), not [Service].
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StartLimitBurst=5
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StartLimitIntervalSec=60s
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[Service]
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Type=simple
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User=left4me
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Group=left4me
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EnvironmentFile=/etc/left4me/host.env
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EnvironmentFile=/var/lib/left4me/instances/%i/instance.env
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# `-` prefix: chdir failure is non-fatal. systemd applies WorkingDirectory
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# before every Exec line — including ExecStartPre — but the merged dir only
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# exists once ExecStartPre's overlay mount succeeds. With `-`, ExecStartPre
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# runs in the unit's home (cwd doesn't matter for the mount helper); the
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# ExecStart re-applies WorkingDirectory after the mount and finds the dir.
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WorkingDirectory=-/var/lib/left4me/runtime/%i/merged/left4dead2
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# Single source of truth for the kernel-overlayfs mount lifecycle: the web
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# app's start_instance only stages cfg files and asks systemd to enable+
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# start this unit; the actual `mount -t overlay` lives here so reboot
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# auto-start works the same as a UI-driven start. ExecStopPost mirrors it
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# so the unmount lives in the same place — no Python-side _mounter needed
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# in stop/delete/reset paths. Both helper verbs are idempotent.
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#
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# `+` prefix runs the helper as PID 1 (root, no sandbox). Required because
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# the unit has NoNewPrivileges=true, which blocks sudo's setuid escalation
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# — and the helper itself needs root to nsenter into PID 1's mnt namespace
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# anyway. ExecStopPost (not ExecStop) so unmount runs after the cgroup is
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# cleared; ExecStop runs while srcds is still alive and would EBUSY.
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ExecStartPre=+/usr/local/libexec/left4me/left4me-overlay mount %i
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ExecStart=/var/lib/left4me/installation/srcds_run -game left4dead2 +hostport ${L4D2_PORT} $L4D2_ARGS
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ExecStopPost=+/usr/local/libexec/left4me/left4me-overlay umount %i
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Restart=on-failure
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RestartSec=5
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# Resource control baseline — see docs/superpowers/specs/2026-05-09-l4d2-server-host-perf-baseline-design.md
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Slice=l4d2-game.slice
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Nice=-5
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IOSchedulingClass=best-effort
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IOSchedulingPriority=4
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OOMScoreAdjust=-200
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MemoryHigh=1.5G
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MemoryMax=2G
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TasksMax=256
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LimitNOFILE=65536
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KillSignal=SIGINT
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TimeoutStopSec=15s
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LogRateLimitIntervalSec=0
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# Hardening (unchanged from previous baseline).
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NoNewPrivileges=true
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PrivateTmp=true
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PrivateDevices=true
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ProtectHome=true
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ProtectSystem=strict
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ReadOnlyPaths=/var/lib/left4me/installation /var/lib/left4me/overlays
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ReadWritePaths=/var/lib/left4me/runtime/%i
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RestrictSUIDSGID=true
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LockPersonality=true
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[Install]
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WantedBy=multi-user.target
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