With 70+ services sharing a handful of common default ports (emby and
jellyfin both default to 8096, changedetection and frigate both default
to 5000, arm and nextcloud both default to 8080...), nothing previously
checked whether a service's default port was actually free on the host.
Whichever service installed second would silently write a compose file
claiming an already-held port, only failing at `docker compose up` time.
Adds two shared helpers to lib/common.sh:
- port_in_use PORT [PROTO] — true if something's already listening
- find_free_port VARNAME START [PROTO] — scans upward, writes back the
first free port
Every service that publishes a fixed host port now scans before writing
docker-compose.yml, on every install (not just when adding an explicit
additional instance). On a normal single-install host this is a silent
no-op; it only changes behavior when something else already holds the
port.
- The 19 services already given multi-instance support this session had
their port scan moved out of the "add instance" branch to run
unconditionally, since the same collision risk exists on a plain first
install.
- 20 more services with previously-hardcoded ports gained scanning for
the first time: archivebox, arm, calibre-web, changedetection,
drum-rhythm-game, gatus, n8n, nextcloud, onlyoffice, stirling-pdf,
uptimekuma, portainer, iopaint (both GPU/CPU compose branches), koha
(paired), syncthing (paired), wg-easy (paired, plus WG_PORT env so
generated peer configs keep the right Endpoint), homeassistant
(bridge-mode only — host mode can only warn), frigate and
frigate-audio (multi-port stacks, moved together).
- caddy.sh is the deliberate exception: 80/443 stay fixed and only warn
on collision, since silently moving Caddy itself would leave nothing
listening where any client actually looks.
- authelia.sh needs no change — it has no published host port at all.
- Every service's standalone bootstrap fallback (sudo bash services/x.sh
with no sibling files) got the same two helpers duplicated into its
stub block, matching how every other shared helper is already handled
there.
Documents the full pattern in CLAUDE.md's new "Port collision avoidance"
section, including the quoted-heredoc/backtick-escaping gotcha and the
network_mode:host limitation (can only scan ports the app takes as a
configurable env var).
Verified via bash -n on every changed file, plus functional runs seeding
occupied ports for each collision shape used here (single, paired,
multi-port stacks) and confirming the scan/shift and generated
compose/README output are correct — including the emby/jellyfin,
nextcloud/arm, and frigate/changedetection collision scenarios that
originally motivated this.
Claude
9e06ed4b83