RomM with Docker Compose

What RomM needs

Only figures RomM's own documentation publishes, each linked to the page it is on. Where the project gives no number, this page does not invent one.

On top of this, Caddy (the reverse proxy in the file) is a single small container. RomM itself runs as 2 containers: romm, romm-db.

Which hardware RomM has images for

Read from each image's manifest list in its registry (anonymous, read-only) when this page was built. An app counts for a CPU only if every one of its images lists it.

• x86-64 PC or NAS (linux/amd64): every image has a build.
• Raspberry Pi 4/5, 64-bit OS (linux/arm64): every image has a build.
• Raspberry Pi 3 or Zero 2 W, 32-bit OS (linux/arm/v7): no image for romm, romm-db. No image for this hardware; the builder leaves the app out.

A manifest says an image exists for a CPU, not how well RomM runs on it: a build for arm64 or arm/v7 can still be too slow or need more memory than the board has. The RAM and disk RomM publishes are in the table above and, for a whole set of apps against a Raspberry Pi, on Will it run on my machine?. A tag like latest can move to a new digest after the date checked.

docker-compose.yml

This is exactly what the builder writes for RomM alone on example.org: the official definition with its published ports removed and Caddy added in front. Every ${VARIABLE} is defined in the .env below.

# docker-compose.yml built at dankhost.com for: RomM
# Each app block is its official compose definition. Only the names were prefixed with
# the app slug (services, containers, volumes, bind folders, .env variables) so any set of
# apps can share one file; other differences are listed under "Changed:" in each block.
# Only Caddy publishes ports. Secrets live in .env next to this file.

services:
  # ---- Caddy: the one reverse proxy, HTTPS certificates from Let's Encrypt ----
  # Source: https://caddyserver.com/docs/running (checked 2026-09-23)
  # Source: https://github.com/dani-garcia/vaultwarden/wiki/Using-Docker-Compose (checked 2026-09-23)
  # Caddyfile goes in ./caddy/Caddyfile. Fixed address 172.30.0.2 so apps can trust it exactly.
  caddy:
    image: "caddy:2"
    container_name: "caddy"
    restart: "unless-stopped"
    ports:
      - "80:80"
      - "443:443"
      - "443:443/udp"
    volumes:
      - "./caddy:/etc/caddy"
      - "caddy-data:/data"
      - "caddy-config:/config"
    networks:
      proxy:
        ipv4_address: "172.30.0.2"

  # ---- RomM (romm.example.org) ----
  # Source: https://github.com/rommapp/romm/blob/master/examples/docker-compose.example.yml (checked 2026-10-08)
  # Source: https://docs.romm.app/latest/getting-started/quick-start/ (checked 2026-10-08)
  # Source: https://docs.romm.app/latest/install/reverse-proxy/ (checked 2026-10-08)
  # Source: https://docs.romm.app/latest/install/backup-and-restore/ (checked 2026-10-08)
  # Source: https://docs.romm.app/latest/administration/authentication/ (checked 2026-10-08)
  # Source: https://docs.romm.app/latest/reference/environment-variables/ (checked 2026-10-08)
  # Changed: Removed the documented '80:8080' port and both container_names; Caddy reaches romm:8080 on the proxy network.
  #          The passwords the file leaves blank are generated in .env: DB_PASSWD, which romm and MARIADB_PASSWORD share as the file asks ("Should match"), and MARIADB_ROOT_PASSWORD. ROMM_AUTH_SECRET_KEY is a 64-digit hex value, the length of the openssl rand -hex 32 the file names.
  #          The metadata-provider keys the file leaves blank (SCREENSCRAPER_USER, SCREENSCRAPER_PASSWORD, RETROACHIEVEMENTS_API_KEY, STEAMGRIDDB_API_KEY) are left out; add the ones you have, as the Metadata Providers page describes.
  #          The /path/to/ folders are ./library (your ROMs), ./assets (saves, states, uploads) and ./config next to this file.
  #          Added: the Authentication page sends password-reset links by email only with ROMM_BASE_URL pointing at a real host, so ROMM_BASE_URL is https://romm.example.org.
  romm:
    image: "rommapp/romm:latest"
    container_name: "romm"
    restart: "unless-stopped"
    environment:
      DB_HOST: "romm-db"
      DB_NAME: "romm"
      DB_USER: "romm-user"
      DB_PASSWD: "${ROMM_DB_PASSWD}"
      ROMM_AUTH_SECRET_KEY: "${ROMM_AUTH_SECRET_KEY}"
      HASHEOUS_API_ENABLED: "true"
      SCAN_WORKERS: "4"
      WEB_SERVER_CONCURRENCY: "4"
      ROMM_BASE_URL: "https://romm.example.org"
    volumes:
      - "romm-romm_resources:/romm/resources"
      - "romm-romm_redis_data:/redis-data"
      - "./romm/library:/romm/library"
      - "./romm/assets:/romm/assets"
      - "./romm/config:/romm/config"
    depends_on:
      romm-db:
        condition: "service_healthy"
        restart: true
    networks:
      proxy: {}
      romm-backend: {}
  romm-db:
    image: "mariadb:latest"
    container_name: "romm-db"
    restart: "unless-stopped"
    environment:
      MARIADB_ROOT_PASSWORD: "${ROMM_MARIADB_ROOT_PASSWORD}"
      MARIADB_DATABASE: "romm"
      MARIADB_USER: "romm-user"
      MARIADB_PASSWORD: "${ROMM_DB_PASSWD}"
    volumes:
      - "romm-mysql_data:/var/lib/mysql"
    healthcheck:
      test:
        - "CMD"
        - "healthcheck.sh"
        - "--connect"
        - "--innodb_initialized"
      start_period: "30s"
      start_interval: "10s"
      interval: "10s"
      timeout: "5s"
      retries: 5
    networks:
      romm-backend: {}

networks:
  # Pinned so the trusted-proxy address given to each app (172.30.0.2) is exact.
  # If "docker compose up" reports "Pool overlaps", change 172.30.0 here, in Caddy's
  # ipv4_address and in every trusted-proxy value to a free 172.x.0 range.
  proxy:
    ipam:
      config:
        - subnet: "172.30.0.0/24"
          ip_range: "172.30.0.128/25"
          gateway: "172.30.0.1"
  romm-backend:
    internal: true

volumes:
  caddy-data:
  caddy-config:
  romm-mysql_data:
  romm-romm_resources:
  romm-romm_redis_data:

Caddyfile save as caddy/Caddyfile

Caddy gets and renews the HTTPS certificate for romm.example.org by itself once the DNS record points at your server and ports 80 and 443 reach it.

# Caddyfile built at dankhost.com. Save it as ./caddy/Caddyfile next to docker-compose.yml.
# Caddy gets and renews a Let's Encrypt certificate for each name below by itself,
# once the DNS records point at this server and ports 80 and 443 reach it.

# RomM
romm.example.org {
	reverse_proxy romm:8080
}

Already running nginx, Nginx Proxy Manager, Caddy or Traefik? The reverse-proxy settings RomM needs, for all four, each cited to RomM's own docs.

.env

The secrets are left blank here on purpose: a password printed on a public page is the same for everyone who copies it. The builder fills them with random letters and digits made in your browser.

# .env for RomM, from dankhost.com/app/romm/. Fill the blank secrets before starting.
# Keep this file private (chmod 600).

# RomM
# 32 random letters and digits: the builder fills this in your browser
ROMM_DB_PASSWD=
# 64 random letters and digits: the builder fills this in your browser
ROMM_AUTH_SECRET_KEY=
# 32 random letters and digits: the builder fills this in your browser
ROMM_MARIADB_ROOT_PASSWORD=

Changes from the official file

Besides prefixing every service, container, volume, folder and variable with romm (so any set of apps can share one file), these are all the differences from what the project documents:

• Removed the documented '80:8080' port and both container_names; Caddy reaches romm:8080 on the proxy network.
• The passwords the file leaves blank are generated in .env: DB_PASSWD, which romm and MARIADB_PASSWORD share as the file asks ("Should match"), and MARIADB_ROOT_PASSWORD. ROMM_AUTH_SECRET_KEY is a 64-digit hex value, the length of the openssl rand -hex 32 the file names.
• The metadata-provider keys the file leaves blank (SCREENSCRAPER_USER, SCREENSCRAPER_PASSWORD, RETROACHIEVEMENTS_API_KEY, STEAMGRIDDB_API_KEY) are left out; add the ones you have, as the Metadata Providers page describes.
• The /path/to/ folders are ./library (your ROMs), ./assets (saves, states, uploads) and ./config next to this file.
• Added: the Authentication page sends password-reset links by email only with ROMM_BASE_URL pointing at a real host, so ROMM_BASE_URL is https://romm.example.org.

Notes for RomM behind the proxy

• Put your games into ./romm/library before the first scan, in the layout the Folder Structure page gives (one folder per platform, such as roms/gba).
• Open https://romm.example.org: the Setup Wizard creates the first user, who always gets the Admin role.
• Matching games to covers and details works best with at least one metadata provider key: the Quick Start calls it "strongly recommended" before your first scan.
• Both images are on latest (rommapp/romm:latest and mariadb:latest), as in the file: every pull can take a new major version of MariaDB. Back up the database before you pull.

Back it up

RomM's Backup & Restore page: the database and /romm/assets are "Critical: back this up nightly", /romm/config is critical but small; resources can be re-downloaded; back up your ROM library separately.

Below is the BACKUP.md the builder writes next to the compose file above: which of its folders and volumes hold data, the dump command the project documents, rewritten for this file's service names, what to copy with which container stopped, and a restore check. Pick more apps in the builder and it covers them all in one file.

# BACKUP.md built at dankhost.com for: RomM

What to copy from the docker-compose.yml built with this file, the database dump each project documents (rewritten for the service names in that file), what to copy with which container stopped, and how to check the result. Run every command in the folder that holds docker-compose.yml.

The folders are owned by the containers' users: put sudo in front of tar if it says "Permission denied". Named volumes live under /var/lib/docker/volumes, not next to the compose file, so they are copied through a throwaway ubuntu container (Docker's documented --volumes-from method). tar makes a full copy each run; for large folders an incremental tool (restic, borg, rsync) saves time and space.

Never run "docker compose down -v" on this file: it deletes the named volumes of every app in it.

## Before you start

    BACKUP=/mnt/backup/selfhost   # change this: a disk or machine other than this server's system disk
    mkdir -p "$BACKUP"

## Every time: the three stack files

    tar czf "$BACKUP/stack-files.tar.gz" docker-compose.yml .env caddy

.env holds the database passwords and secret keys the apps were set up with; keep this archive as private as the data.

## Caddy (the reverse proxy)

Caddy's docs: 'The data directory must not be treated as a cache.' It holds the TLS certificates and their private keys; without it Caddy has to ask Let's Encrypt for every certificate again.

- caddy-data (named volume, /data in caddy)
  BACK UP: TLS certificates, private keys, OCSP staples.
- caddy-config (named volume, /config in caddy)
  SKIP: the last active configuration, kept for 'caddy run --resume', which this setup does not use: it starts from the Caddyfile.
- ./caddy (/etc/caddy in caddy)
  IN stack-files.tar.gz: the Caddyfile, copied with the stack files above.

Copy (Caddy keeps serving while you copy):

    docker run --rm --volumes-from caddy -v "$BACKUP":/backup ubuntu tar cvf /backup/caddy-data.tar /data

Restore check:

    tar tf "$BACKUP/caddy-data.tar" > /dev/null && echo OK
    docker run --rm --volumes-from caddy -v "$BACKUP":/backup ubuntu bash -c "cd /data && tar xvf /backup/caddy-data.tar --strip 1"

Sources:
- Caddy docs: Conventions, Data directory: https://caddyserver.com/docs/conventions#data-directory (checked 2026-09-24)
- Docker docs: Volumes, Back up, restore, or migrate data volumes: https://docs.docker.com/engine/storage/volumes/#back-up-restore-or-migrate-data-volumes (checked 2026-09-24)

## RomM

RomM's Backup & Restore page: the database and /romm/assets are "Critical: back this up nightly", /romm/config is critical but small; resources can be re-downloaded; back up your ROM library separately.

What this compose mounts:
- romm-romm_resources (named volume, /romm/resources in romm)
  OPTIONAL: covers and screenshots fetched from the metadata providers; a rescan downloads them again, keeping them only speeds up recovery.
- romm-romm_redis_data (named volume, /redis-data in romm)
  SKIP: the task queue: in-flight tasks only, which can be re-run.
- ./romm/library (/romm/library in romm)
  OPTIONAL: your ROM files. The page: "Back this up separately. It's your source data."
- ./romm/assets (/romm/assets in romm)
  BACK UP: save files, save states, uploaded screenshots, manuals and covers.
- ./romm/config (/romm/config in romm)
  BACK UP: config.yml and any overrides.
- romm-mysql_data (named volume, /var/lib/mysql in romm-db)
  COVERED BY THE COMMAND BELOW: MariaDB's data files: users, ROM metadata, collections, play sessions. The dump below is the copy to keep.

1. Database dump for romm-db:

    docker compose exec -T romm-db sh -c 'mariadb-dump --user="$MARIADB_USER" --password="$MARIADB_PASSWORD" --single-transaction --databases romm' > "$BACKUP/romm-db.sql"

   The page's MariaDB dump, run inside the database container, which already has the user and password in its environment, so no password is typed on the host.

2. Copy (RomM keeps running):
   The page warns that a live copy of the database volume can be inconsistent and uses a logical dump instead, which is consistent while RomM runs (--single-transaction).

    tar czf "$BACKUP/romm-assets.tar.gz" ./romm/assets
    tar czf "$BACKUP/romm-config.tar.gz" ./romm/config

Restore check:

    grep -c 'Dump completed' "$BACKUP/romm-db.sql"   # 1 means mariadb-dump finished
    tar tzf "$BACKUP/romm-assets.tar.gz" > /dev/null && echo OK
    tar tzf "$BACKUP/romm-config.tar.gz" > /dev/null && echo OK

Put a copy back (with RomM stopped):

    tar xzf "$BACKUP/romm-assets.tar.gz"   # recreates ./romm/assets; move the old folder aside first
    tar xzf "$BACKUP/romm-config.tar.gz"   # recreates ./romm/config; move the old folder aside first

Into a fresh install with the same ROMM_AUTH_SECRET_KEY (the page: a new secret invalidates sessions and invite links). Let the first start finish, then:

    docker compose stop romm
    docker compose exec -T romm-db sh -c 'mariadb --user="$MARIADB_USER" --password="$MARIADB_PASSWORD"' < "$BACKUP/romm-db.sql"

Put ./romm/assets and ./romm/config back, then:

    docker compose up -d

Sources:
- RomM docs: Backup & Restore (database dump, assets, config): https://docs.romm.app/latest/install/backup-and-restore/ (checked 2026-10-08)
- Docker docs: Volumes, Back up, restore, or migrate data volumes: https://docs.docker.com/engine/storage/volumes/#back-up-restore-or-migrate-data-volumes (checked 2026-10-08)

Update it

What docker compose pull does depends only on how each image line in the compose file above is tagged. For RomM as this page writes it:

What RomM's docs say about updating

RomM publishes no update procedure for this setup; the steps below are Docker's generic method.

The steps

1. Back up first, as in Back it up above. An update can migrate RomM's data on its first start and its database with it; the copy is the way back.
2. Download the new images. Running containers are not touched yet:

   docker compose pull

3. Recreate the containers whose image changed. Volumes and bind-mounted folders stay as they are:

   docker compose up -d

4. Watch RomM start (Ctrl+C stops following the log, not the app):

   docker compose logs -f romm

5. Optional: remove the old images the pull left without a tag. This covers every stack on the machine, not only this one:

   docker image prune

Docker's reference for these commands: Docker docs: docker compose pull checked 2026-09-30; Docker docs: docker compose up (recreates changed containers, keeps volumes) checked 2026-09-30; Docker docs: docker image prune checked 2026-09-30

Locked out? Reset the admin password

RomM resets a forgotten password with a link from the sign-in page. Without email set up, the link is written to the container log.

1. On the sign-in page, ask for a password reset for your username. It works once within 10 minutes. Source: RomM docs: Authentication (Password reset: email or container log) read 2026-10-08
2. This compose file sets no SMTP server, so RomM writes the link to its log ("the link is written to the container log for an admin to pass on"). Find it there and open it: Source: RomM docs: Authentication (Password reset: email or container log) read 2026-10-08; Docker docs: docker compose logs read 2026-10-03

   docker compose logs romm

3. If you turned password logins off (DISABLE_USERPASS_LOGIN=true) and OIDC broke, the troubleshooting page's way back is to unset it and run docker compose up -d. Source: RomM docs: Troubleshooting, Authentication (Password logins are disabled, OIDC is broken) read 2026-10-08

Run the commands in the folder that holds docker-compose.yml.

Sources

Every page below was fetched on the date shown.

• RomM on GitHub (repository description) checked 2026-10-08 (what it does)
• RomM: examples/docker-compose.example.yml (romm, romm-db) checked 2026-10-08 (compose definition and proxy settings)
• RomM docs: Quick Start (Docker Compose, Setup Wizard) checked 2026-10-08 (compose definition and proxy settings)
• RomM docs: Reverse Proxy (port 8080, nginx WebSocket headers, client_max_body_size 0) checked 2026-10-08 (compose definition and proxy settings)
• RomM docs: Backup & Restore (database dump, assets, config) checked 2026-10-08 (compose definition and proxy settings, backup plan)
• RomM docs: Authentication (Password reset: email or container log) checked 2026-10-08 (compose definition and proxy settings)
• RomM docs: Environment Variables (ROMM_AUTH_SECRET_KEY, DB_PASSWD) checked 2026-10-08 (compose definition and proxy settings)
• Caddy docs: Keep Caddy running (Docker Compose section) checked 2026-09-23 (Caddy)
• Vaultwarden wiki: Caddy with HTTP challenge (uses the caddy:2 image) checked 2026-09-23 (Caddy)
• Docker docs: Volumes, Back up, restore, or migrate data volumes checked 2026-10-08 (backup plan)
• Caddy docs: Conventions, Data directory checked 2026-09-24 (backup plan)
• MariaDB Docker Official Image: MARIADB_AUTO_UPGRADE checked 2026-09-30 (database upgrade)
• Docker docs: docker compose pull checked 2026-09-30 (update steps)
• Docker docs: docker compose up (recreates changed containers, keeps volumes) checked 2026-09-30 (update steps)
• Docker docs: docker image prune checked 2026-09-30 (update steps)

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