Explicit clarification so the next agent doesn't go looking for
user-unit friction. left4me-server@.service and left4me-web.service
are system units that drop to User=left4me; the 3-user split is a
literal one-line edit per unit. No lingering, no pam_systemd, no
per-user systemd instance bootstrap. The privileged
ExecStartPre/ExecStopPost steps stay root via the + prefix.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
The 2-user split (left4me + l4d2-sandbox) has been inherited as a
constraint across multiple recent plans (idmap-on-mount, build-time-
idmap, helper consolidation) without ever being designed
end-to-end. Three plausible configurations: collapse to 1 user
(rejected for security), keep at 2 users (status quo), or split web
from game into 3 users for blast-radius limiting on either side.
Doc captures the threat-model heuristics, cross-uid file-access
plumbing options (shared group vs. world-read), idmap implications,
a step-by-step migration sketch for the 3-user variant, and explicit
out-of-scope items (per-instance gameserver uids, etc.). Detailed
enough that a future session can pick a configuration and execute
without re-deriving the design space.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
