The job worker calls fusermount3 (setuid-root) to mount per-instance
FUSE overlays and sudo to invoke the privileged systemctl wrapper.
NoNewPrivileges=true blocks both, surfacing as
"fusermount3: mount failed: Operation not permitted" the first time a
server is started. Hardening is still enforced via dedicated user,
PrivateTmp, ProtectSystem=full, ReadWritePaths, and the narrow sudoers
allowlist limited to two helper scripts.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
