Kimai in Docker.
Time tracking, production ready.

Architecture at a glance

• Kimai (Apache and PHP) serves plain HTTP on port 8001. TLS is terminated upstream by a reverse proxy (Traefik on the RemarkableCloud App Platform); with TRUSTED_PROXIES set, Kimai derives https URLs from the forwarded headers.
• MariaDB is a separate database container and holds all timesheets and configuration.
• A data volume at /opt/kimai/var/data holds the APP_SECRET and uploaded data. Application code stays in the image.

Docker Compose walkthrough

The standalone stack (Kimai and MariaDB) is defined in the image’s docker-compose.yml:

name: kimai
services:
  db:
    image: mariadb:11
    restart: unless-stopped
    environment:
      MARIADB_DATABASE: kimai
      MARIADB_USER: kimai
      MARIADB_PASSWORD: ${DB_PASSWORD:-change-me-db}
      MARIADB_ROOT_PASSWORD: ${DB_ROOT_PASSWORD:-change-me-root}
    volumes: [db-data:/var/lib/mysql]
    healthcheck:
      test: ["CMD", "healthcheck.sh", "--connect", "--innodb_initialized"]
      interval: 10s
      timeout: 5s
      retries: 12
  kimai:
    image: ${KIMAI_IMAGE:-ghcr.io/remarkablecloud/kimai:2.66.0-r1}
    restart: unless-stopped
    depends_on:
      db:
        condition: service_healthy
    ports: ["${HTTP_PORT:-8098}:8001"]
    environment:
      KIMAI_DB_HOST: db
      KIMAI_DB_PORT: "3306"
      KIMAI_DB_NAME: kimai
      KIMAI_DB_USER: kimai
      KIMAI_DB_PASSWORD: ${DB_PASSWORD:-change-me-db}
      ADMINMAIL: ${ADMINMAIL:-admin@example.com}
      ADMINPASS: ${ADMINPASS:-}
    volumes:
      - kimai-data:/opt/kimai/var/data
volumes:
  db-data:
  kimai-data:

Step by step:

1. The app waits for the database. depends_on with condition: service_healthy avoids a first-boot race, and Kimai’s entrypoint also waits for the connection.
2. Install is env-driven. The KIMAI_DB_* variables drive migrations and admin creation; no web wizard.
3. The admin password is generated if blank. Leave ADMINPASS empty and the image creates a strong one on first run and logs it once.
4. The web port is 8001. ${HTTP_PORT:-8098}:8001 maps it for local use; in production the proxy connects to port 8001 on the internal network.
5. State lives in volumes. kimai-data (var/data) and db-data persist across restarts and upgrades.

To start it locally:

DB_PASSWORD=$(openssl rand -hex 16) docker compose up -d

Then browse to http://localhost:8098 and read the admin login from docker compose logs kimai. For production, put the container behind a TLS-terminating reverse proxy; Kimai derives the scheme from the forwarded headers.

Environment variable reference

These are wired automatically by the App Platform backend from the managed MariaDB; they are listed here for standalone and self-hosted runs.

Variable	Required	Value / default	Purpose
KIMAI_DB_HOST	yes	<db_host>	MariaDB host.
KIMAI_DB_PORT	no	3306	MariaDB port.
KIMAI_DB_NAME	yes	<db_name>	Database name.
KIMAI_DB_USER	yes	<db_user>	Database user.
KIMAI_DB_PASSWORD	yes	<db_password>	Database password (URL-encoded into DATABASE_URL).
ADMINMAIL	no	admin@example.com	Admin email created at install.
ADMINPASS	no	(generated)	Admin password. Leave empty to auto-generate on first run (printed once); set it to pin your own.

You can also pass a full DATABASE_URL directly instead of the parts. Only the first run reads the admin variables.

Hardening notes

• No default credentials. The admin password is generated at first run or supplied by you, never baked into an image layer.
• Unique, persistent APP_SECRET. Generated on first run and kept in var/data, never the public default.
• Digest-pinned base. Each build is auditable and reproducible.
• Healthcheck gates traffic. The app must respond before the platform routes requests.
• Keep MariaDB private. Do not publish its port to the host or the internet.
• After first login, create per-user accounts, keep Kimai updated, and enable two-factor authentication.

Backups

Capture the database and the data volume together:

1. The MariaDB database:

   docker compose exec db mariadb-dump -u root -p"$DB_ROOT_PASSWORD" kimai > kimai-db.sql

2. The data volume at var/data (APP_SECRET and uploaded data):

   docker run --rm -v kimai_kimai-data:/data -v "$PWD":/backup alpine \
     tar czf /backup/kimai-data.tgz -C /data .

Keep the APP_SECRET (in var/data) with the database backup. On the RemarkableCloud App Platform, database and volume backups follow the platform’s backup schedule.

Upgrades

• New builds ship as new -r tags. Because the application lives in the image and only var/data is persisted, pulling a new tag updates Kimai; migrations run on start:

  docker compose pull kimai && docker compose up -d kimai

• Back up first, and keep the database dump and the var/data archive from just before the upgrade.
• Read the changelog. Every build is listed in CHANGELOG.md with the base image digest and any behavior changes.