docker-compose.yml

version: "3.3"

networks:
  # Use the previously created public network "traefik-public", shared with other
  # services that need to be publicly available via this Traefik
  traefik-public:
    external: true

volumes:
  # Create a volume to store the certificates, there is a constraint to make sure
  # Traefik is always deployed to the same Docker node with the same volume containing
  # the HTTPS certificates
  traefik-public-certificates:

services:
  node-exporter:
    image: "quay.io/prometheus/node-exporter"
    pid: host
    volumes:
      - "/:/host:ro,rslave"
    command:
      - "--path.rootfs=/host"
      - "--web.telemetry-path=/host-metrics"

    networks:
      - traefik-public
    
    deploy:
      placement:
        constraints:
          # Make the traefik service run only on the node with this label
          # as the node with it has the volume for the certificates
          - node.labels.traefik-public.traefik-public-certificates == true
      labels:
        - traefik.enable=true
        - traefik.constraint-label=traefik-public
        - traefik.http.routers.node_exporter.rule=Host(`${DOMAIN}`) && PathPrefix(`/host-metrics`)
        - traefik.http.routers.node_exporter.entrypoints=websecure
        - traefik.http.routers.node_exporter.tls.certresolver=le
        - traefik.http.routers.node_exporter.middlewares=admin-auth
        - traefik.http.services.node_exporter.loadbalancer.server.port=9100
    
  traefik:
    image: "traefik:v2.8"

    ports:
      # Listen on port 80, default for HTTP, necessary to redirect to HTTPS
      - target: 80
        published: 80
        mode: host
        
      # Listen on port 443, default for HTTPS
      - target: 443
        published: 443
        mode: host

    deploy:
      placement:
        constraints:
          # Make the traefik service run only on the node with this label
          # as the node with it has the volume for the certificates
          - node.labels.traefik-public.traefik-public-certificates == true

      labels:
        # Enable Traefik for this service, to make it available in the public network
        - traefik.enable=true

        # Use the traefik-public network (declared below)
        - traefik.docker.network=traefik-public

        # Use the custom label "traefik.constraint-label=traefik-public"
        # This public Traefik will only use services with this label
        # That way you can add other internal Traefik instances per stack if needed
        - traefik.constraint-label=traefik-public

        # admin-auth middleware with HTTP Basic auth
        # Using the environment variables DASHBOARD_PASSWORD
        - traefik.http.middlewares.admin-auth.basicauth.users=admin:${DASHBOARD_PASSWORD?Variable not set}

        # https-redirect middleware to redirect HTTP to HTTPS
        # It can be re-used by other stacks in other Docker Compose files
        - traefik.http.middlewares.https-redirect.redirectscheme.scheme=https
        - traefik.http.middlewares.https-redirect.redirectscheme.permanent=true

        # traefik-http set up only to use the middleware to redirect to https
        # Uses the environment variable DOMAIN
        - traefik.http.routers.traefik-public-http.rule=Host(`${DOMAIN?Variable not set}`)
        - traefik.http.routers.traefik-public-http.entrypoints=web
        - traefik.http.routers.traefik-public-http.middlewares=https-redirect
        
        # traefik-https the actual router using HTTPS
        # Uses the environment variable DOMAIN
        - traefik.http.routers.traefik-public-https.rule=Host(`${DOMAIN?Variable not set}`)
        - traefik.http.routers.traefik-public-https.entrypoints=websecure
        - traefik.http.routers.traefik-public-https.tls=true
        
        # Use the special Traefik service api@internal with the web UI/Dashboard
        - traefik.http.routers.traefik-public-https.service=api@internal
        # Use the "le" (Let's Encrypt) resolver created below
        - traefik.http.routers.traefik-public-https.tls.certresolver=le
        # Enable HTTP Basic auth, using the middleware created above
        - traefik.http.routers.traefik-public-https.middlewares=admin-auth
        # Define the port inside of the Docker service to use
        - traefik.http.services.traefik-public.loadbalancer.server.port=8080

    command:
      # Enable the access log, with HTTP requests
      - --accesslog
      
      # Enable the Traefik log, for configurations and errors
      - --log
      - --log.level=INFO

      # Enable the Dashboard and API
      - --api
      - --api.dashboard

      - "--metrics.prometheus.manualrouting=true"
      - "--global.sendAnonymousUsage"
      
      # Enable Docker in Traefik, so that it reads labels from Docker services
      - --providers.docker
      # Enable Docker Swarm mode
      - --providers.docker.swarmmode
      # Add a constraint to only use services with the label "traefik.constraint-label=traefik-public"
      - --providers.docker.constraints=Label(`traefik.constraint-label`, `traefik-public`)
      # Do not expose all Docker services, only the ones explicitly exposed
      - --providers.docker.exposedbydefault=false

      # Create an entrypoint "web" listening on port 80
      - --entrypoints.web.address=:80

      # Create an entrypoint "websecure" listening on port 443
      - --entrypoints.websecure.address=:443

      # Create the certificate resolver "le" for Let's Encrypt, uses the environment variable EMAIL
      - --certificatesresolvers.le.acme.email=${LETSENCRYPT_EMAIL?Variable not set}
      # Store the Let's Encrypt certificates in the mounted volume
      - --certificatesresolvers.le.acme.storage=/certificates/acme.json
      # Use the TLS Challenge for Let's Encrypt
      - --certificatesresolvers.le.acme.tlschallenge=true
      # Make sure we're using the new chain
      - --certificatesresolvers.le.acme.preferredChain=ISRG Root X1

    volumes:
      # Add Docker as a mounted volume, so that Traefik can read the labels of other services
      - /var/run/docker.sock:/var/run/docker.sock:ro
      # Mount the volume to store the certificates
      - traefik-public-certificates:/certificates
    
    environment:
      - DASHBOARD_PASSWORD
    
    networks:
      # Use the public network created to be shared between Traefik and
      # any other service that needs to be publicly available with HTTPS
      - traefik-public