I am very new to using docker. I have been used to using dedicated VM’s and hosting the applications within the servers OS.

When hosting multiple applications/services that require the same port, is it best practice to spin up a whole new docker server or how should I go about the conflicts?

Ie. Hosting multiple web applications that utilize 443.

Thank you!

  • Scott@lem.free.asEnglish
    4·
    1 year ago

    Use a single reverse proxy on that one port… it can then route the requests to the various back ends.

    You probably want something that’s Docker-native like Traefik or Caddy.

    • EliteCow@lemmy.dbzer0.comOPEnglish
      2·
      1 year ago

      Thank you! I am using Caddy and was able to define a unique random port for the other containers and access this via reverse proxy!

      • herrfrutti@lemmy.worldEnglish
        3·
        1 year ago

        If the containers are all in the same network. You dont need to expose a port.

        Lets assume you create a docker network called reverse_proxy and add all your contaiers that you want to be accessed by the reverse proxy to that network (including caddy).

        Then you can address all containers through the hostname in you caddy file and the port would be the default configurated port from the container.

        So in the end you just expose the caddy container and nothing more.

        • d_k_bo@feddit.deEnglish
          1·
          1 year ago

          That wouldn’t work if multiple containers use the same port (eg. 8000), right?

          Without a docker network, I can just map 8001:8000 and don’t have that issue.

          • aguslr@lemmy.sdf.orgEnglish
            1·
            1 year ago

            Yes, it’d work just fine because each container listens on port 8000 of their own IP address, not the docker server’s IP address. Caddy/Traefik just redirects traffic to that port.

        • EliteCow@lemmy.dbzer0.comOPEnglish
          1·
          1 year ago

          In addition to Caddy being apart of the reverse_proxy network. Would I also have to add it to the Bridge network so that I can utilize the machine IP that docker is hosted on for port forwarding 443?

          • herrfrutti@lemmy.worldEnglish
            5·
            1 year ago

            Caddy would have the bridge proxy network and the port 443 exposed.

            version: "3.7"

networks:
  proxy-network:
    external: true
# needs to be created manually bevor running (docker create network proxy-network)
services:
  caddy:
    image: caddy
    container_name: caddy
    restart: unless-stopped
    ports:
      - 80:80
      - 443:443
    volumes:
      - ./data:/data
      - ./config:/config
      - ./Caddyfile:/etc/caddy/Caddyfile:ro
    networks:
      - proxy-network

            Other services:

            version: "3.7"

networks:
  proxy-network:
    external: true

services:
  app:
    image: app
    container_name: app
    restart: unless-stopped
    volumes:
      - ./app-data:/data
    networks:
      - proxy-network

            Caddy can now talk to the app with the apps container_name.

            Caddyfile:

            homepage.domain.de {
    reverse_proxy app:80
}

            So the reverse proxy network is an extra network only for containers that need to be exposed.

  • pacoboyd@lemm.eeEnglish
    3·
    1 year ago

    That’s the cool thing about docker you can just map a different external port.

    https://docs.docker.com/network/

    So if you look at the first flag it mentions: -p 8080:80

    This means it’s mapping external port 8080 to the internal port 80. You can change the 8080 to anything you want so you don’t have conflicts.

    • EliteCow@lemmy.dbzer0.comOPEnglish
      0·
      1 year ago

      I have done what you mentioned and used a random port internally and kept 443 as the listening port. I am using Caddy to then direct the traffic reverse proxy it.

      Thank you so much!

      • pacoboyd@lemm.eeEnglish
        1·
        1 year ago

        Just FYI, we may be using “internally” differently, but you can’t change the port number to the right of the “:” That’s usually a fixed port needed for the container (the internal docker port).

        I think you are using “internal” to mean your local network port though, but in Dockers case it would be the “external port” (external to docker).

        Flow would be: Proxy → External Docker Port (8080, can be variable) → Internal Docker Port (80, fixed per docker container)

        Probably getting overly picky with wording, but wanted to make sure you knew that the inernal docker port can’t be changed, just the mapping.

  • flunky@lemmy.flunky.clubEnglish
    1·
    1 year ago

    For hosting multiple web apps, what you probably want is a reverse proxy. I recently started using Caddy (specifically Caddy-Docker-Proxy), and I’m liking it. There’s also Traefik, nginx, etc.

    For other types of services, you can simply map whatever (available) port you like in your docker compose file. See here: https://docs.docker.com/compose/networking/