Setup Adminer, Postgres and Traefik on a single VPS

Hi there,

Setting up Adminer, PostgreSQL, and Traefik on a single VPS using Docker and docker-compose is a common scenario. Your goal of having a single instance of Adminer for the entire VPS is practical, and it can be achieved by correctly configuring your Docker networks.

The key here is to ensure that Adminer is on the same network as your PostgreSQL database so it can communicate with it, and also on the network used by Traefik for routing.

Based on your provided docker-compose files, here’s a suggested setup:

1. Traefik and Adminer Setup: In your reverse proxy docker-compose file where you have Traefik and want to add Adminer, you’re on the right track. You’ll need to make sure that Adminer is on the proxy network so that Traefik can route requests to it. Your configuration for this part seems correct.

2. PostgreSQL Setup: In your application’s docker-compose file, where you have your PostgreSQL database, you should ensure that the database is also on the proxy network. This allows Traefik to manage requests to the database if needed (for external connections). However, for Adminer to access PostgreSQL, they don’t necessarily need to be on the same network since Adminer can connect to PostgreSQL using the internal Docker DNS system.

3. Internal Network: You mentioned an internal network, which is great for internal communication between your app and the database. But since Adminer will be connecting from a different docker-compose setup, it won’t have access to this internal network. You can either add Adminer to this internal network or use the Docker DNS system for Adminer to connect to the PostgreSQL database.

4. Connecting Adminer to PostgreSQL: Adminer will need the hostname of your PostgreSQL container to connect to it. In Docker, the default network mode provides a DNS resolver that allows containers to communicate by container names. So, in Adminer, you should be able to use the name of your PostgreSQL service (e.g., postgres-db-prod) as the host to connect to.

5. External Access to PostgreSQL: If you need PostgreSQL to be accessible from external servers (as mentioned for GitHub actions), the ports configuration in your PostgreSQL service is necessary. Just ensure that your VPS and firewalls are configured to allow traffic on the relevant port (5432 in this case).

Here’s a revision of your setup with these considerations:

# Docker-compose for Traefik and Adminer
services:
  traefik:
    # ... your traefik configuration
    networks:
      - proxy

  adminer:
    image: adminer:4.8.1-standalone
    networks:
      - proxy
    labels:
      - "traefik.http.routers.adminer.rule=Host(`adminer.${DOMAIN}`)"
      - "traefik.http.services.adminer.loadbalancer.server.port=8080"

networks:
  proxy:
    external: true

# Docker-compose for your app and PostgreSQL
services:
  app:
    # ... your app configuration
    networks:
      - internal

  postgres-db-prod:
    image: postgres:14-alpine
    container_name: postgres-db-prod
    restart: unless-stopped
    ports:
      - "5432:5432"
    volumes:
      - ./prisma/pg-data:/var/lib/postgresql/data
    env_file:
      - .env.local
    networks:
      - internal

networks:
  internal:
    name: internal_network


    driver: bridge

# Note: No need to attach 'postgres-db-prod' to the 'proxy' network
# as it's not directly served by Traefik. Adminer accesses it over Docker's internal DNS.

In this configuration:

• Both Adminer and PostgreSQL are on their respective networks. Adminer uses the proxy network to be reachable via Traefik, and PostgreSQL is on the internal network for communication with your app.
• Adminer can connect to PostgreSQL using the PostgreSQL container’s name (postgres-db-prod) as the host in the connection settings.
• The internal network is defined to facilitate communication between your app and the PostgreSQL database.
• PostgreSQL is exposed on port 5432 for external connections, as needed for your GitHub actions.

This setup should allow you to have a single Adminer instance on your VPS that can access your PostgreSQL database, while also maintaining the necessary network separations for security and organization. Remember to replace internal_network with a unique name specific to your setup to avoid conflicts with other networks.

Best,

Bobby