How to Deploy Adminer 4.8.1 Database Management Tool in Docker Swarm Behind Traefik v2.0

Adminer is a lightweight, web-based database management tool designed for administrators and developers who prefer a visual interface over the command line.

In a previous tutorial, we explored deploying MariaDB in a Docker Swarm cluster and managing it through the CLI. While the terminal offers precision and speed, a visual dashboard is often more convenient for daily query execution, table schema inspection, and data exploration. In this guide, we will deploy Adminer 4.8.1 inside a Docker Swarm cluster behind Traefik v2.0 with automatic SSL termination.

Prerequisites

Ensure you have the following components in place before deploying:

1. A functional Docker Swarm Cluster with distributed shared storage (such as GlusterFS).
2. Traefik v2.0 deployed as the ingress reverse proxy on an overlay network named proxy.
3. An active database service (such as MariaDB) reachable across the Swarm network.

What is Adminer?

Adminer (formerly known as phpMinAdmin) is an open-source database administration tool distributed under the Apache License (or GPL v2). Unlike phpMyAdmin, which consists of thousands of files, Adminer is packaged as a single, highly optimized PHP file roughly 470 KB in size.

It provides native support for multiple database management systems, including MySQL, MariaDB, PostgreSQL, Microsoft SQL Server, SQLite, Oracle, Firebird, SimpleDB, Elasticsearch, and MongoDB.

Why Choose Adminer over phpMyAdmin?

While phpMyAdmin remains widely known, Adminer was built from the ground up to address its core limitations:

• Resource Footprint: Consists of a single script, reducing storage overhead and attack surface.
• Performance: Significantly lower execution overhead and faster page load speeds.
• Broad Database Support: Works seamlessly across diverse SQL and NoSQL engines.
• Enhanced Security: Less susceptible to legacy CVEs and heavy framework exploits.

Key Capabilities

• Authenticate against remote servers using standard database credentials.
• Create, modify, and drop databases, schemas, views, and stored routines.
• Inspect and alter table structures, column definitions, data types, indexes, and full-text keys.
• Manage relationships and foreign constraints visually during schema design.
• Execute ad-hoc SQL statements via an interactive text editor or script upload.
• Export table structures, datasets, or full schemas into SQL dumps or CSV format.

Prepare the Deployment Directory

Create a dedicated directory under /opt to store the Docker Swarm deployment stack:

cd /opt
sudo mkdir -p adminer
cd adminer
sudo touch adminer.yml

Docker Compose Stack Definition

Open adminer.yml in your editor of choice:

sudo nano adminer.yml

Add the following stack specification:

version: "3.7"

services:
  adminer:
    image: adminer:4.8.1
    ports:
      - "5000:8080"
    environment:
      - PMA_HOST=testdb:3306
      - MYSQL_USER=testuser
      - MYSQL_PASSWORD=password
    networks:
      - proxy
    deploy:
      replicas: 1
      placement:
        constraints:
          - node.role == worker
      update_config:
        parallelism: 2
        delay: 10s
      restart_policy:
        condition: on-failure
      labels:
        - "traefik.enable=true"
        - "traefik.docker.network=proxy"
        - "traefik.http.routers.adminer.rule=Host(`dbadmin.example.com`)"
        - "traefik.http.routers.adminer.entrypoints=websecure"
        - "traefik.http.routers.adminer.tls=true"
        - "traefik.http.routers.adminer.tls.certresolver=default"
        - "traefik.http.services.adminer.loadbalancer.server.port=8080"

networks:
  proxy:
    external: true

Configuration Details:

• Port Mapping (5000:8080): Adminer listens internally on port 8080. We publish port 5000 on the host to avoid potential port conflicts with the Traefik dashboard.
• Overlay Network (proxy): Connects Adminer to the existing ingress network where Traefik routes inbound HTTP/HTTPS traffic.
• Traefik Routing Labels: Tells Traefik to automatically discover the container, match requests on dbadmin.example.com, and acquire Let’s Encrypt certificates using the default resolver.

Deploy Adminer to the Swarm

Deploy the service stack using the Docker CLI:

docker stack deploy --compose-file adminer.yml adminer

Verify that the task has scheduled and started successfully:

docker stack ps adminer

Accessing the Web Interface

Once DNS has propagated, open your browser and navigate to https://dbadmin.example.com.

Log in by providing the target database server hostname (such as testdb within the Docker overlay network), database username, and password:

Upon authentication, the full management console becomes available:

Summary

Adminer provides an agile, low-maintenance approach to database management in distributed container environments. In upcoming guides, we will explore deploying enterprise workloads—including Nextcloud, Rocket.Chat, and Wekan—onto Docker Swarm with automated reverse proxying.