Traefik

Traefik is a Modern HTTP Reverse Proxy and Load Balancer that makes deploying microservices easily.

The Proxy

To run a traefik service with docker-compose, the section will look like this:

...
  traefik:
    image: traefik:v2.4.5
    container_name: traefik
    command: [ '--providers.docker', '--api.insecure' ]
    networks:
      - contained
    ports:
      - 80:80
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
    labels:
      - "traefik.http.routers.traefik.rule=Host(`traefik.localdns.xyz`)"
      - "traefik.http.services.traefik.loadbalancer.server.port=8080"
...

As you can see we are exposing port 80 as we are only running this example in http, mounting the docker.sock so that traefik can read docker events and read information about other containers.

Then the labels is where the magic happens, we are defining the host rule traefik.localdns.xyz to route to port 8080 on the traefik service.

Reverse Proxy to a Web App

Now if we want to use traefik as a reverse proxy to a web application, we define the bit like this:

...
  web-center-name:
    image: ruanbekker/web-center-name-v2
    container_name: web-center-name
    environment:
      - APP_TITLE=Welcome
      - APP_URL=https://ruan.dev
      - APP_TEXT=Visit my Website
    networks:
      - contained
    depends_on:
      - traefik
    labels:
      - "traefik.http.routers.minio.rule=Host(`www.localdns.xyz`)"
      - "traefik.http.services.minio.loadbalancer.server.port=5000"
...

The full example of our docker-compose.yml will look like this:

version: "3.9"

services:
  traefik:
    image: traefik:v2.4.5
    container_name: traefik
    command: [ '--providers.docker', '--api.insecure' ]
    networks:
      - contained
    ports:
      - 80:80
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
    labels:
      - "traefik.http.routers.traefik.rule=Host(`traefik.localdns.xyz`)"
      - "traefik.http.services.traefik.loadbalancer.server.port=8080"

  web-center-name:
    image: ruanbekker/web-center-name-v2
    container_name: web-center-name
    environment:
      - APP_TITLE=Welcome
      - APP_URL=https://ruan.dev
      - APP_TEXT=Visit my Website
    networks:
      - contained
    depends_on:
      - traefik
    labels:
      - "traefik.http.routers.minio.rule=Host(`www.localdns.xyz`)"
      - "traefik.http.services.minio.loadbalancer.server.port=5000"

networks:
  contained:
    name: contained

To boot our service:

docker-compose -f docker-compose.yml up -d

And testing our application:

curl -I http://www.localdns.xyz

HTTP/1.1 200 OK
Content-Length: 1939
Content-Type: text/html; charset=utf-8
Date: Wed, 31 Mar 2021 14:46:22 GMT
Server: Werkzeug/1.0.1 Python/3.9.2