How to have duplicate Port (I'm using different network)

Docker Desktop for Windows
1

Dear folks,
I’m using PostgreSQL for my company project, which is configured by them, and uses the default port.
And I also configured the SonarQube with standalone database (PostgreSQL). I also defined an network for it. and in the end, I only used the default port for internal, but used another port number for external port.
Still it says the port are duplicated.

Any solution?

Thank you,
Hassan F.

version: "3.9"
name: Sonar
services:
  postgres:
    image: postgres:latest
    container_name: sonar.postgres
    ports: 
      - "5432:65432"
    networks:
      - sonarnet
    environment:
      - POSTGRES_USER=sonar
      - POSTGRES_PASSWORD=Pa$$word123
    volumes:
      - sonar_postgresql:/var/lib/postgresql
      - sonar_postgresql_data:/var/lib/postgresql/data
    deploy:
      restart_policy:
        condition: unless-stopped

  sonarqube:
    image: sonarqube:latest
    container_name: sonarqube
    ports: 
      - "9000:9000"
    networks:
      - sonarnet
    environment: #internal port
      - sonar.jdbc.url=jdbc:postgresql://postgres:5432/postgres
      - sonar.jdbc.username=sonar
      - sonar.jdbc.password=Pa$$word123
      - sonar.search.javaAdditionalOpts=-Dnode.store.allow_mmap=false
    volumes:
      - sonarqube_conf:/opt/sonarqube/conf
      - sonarqube_data:/opt/sonarqube/data
      - sonarqube_extensions:/opt/sonarqube/extensions
      - sonarqube_logs:/opt/sonarqube/logs
    deploy:
      restart_policy:
        condition: unless-stopped
    depends_on:
      - postgres
      
networks:
  sonarnet:
    driver: bridge
    
volumes:
  sonarqube_conf:
  sonarqube_data:
  sonarqube_extensions:
  sonarqube_logs:
  sonar_postgresql:
  sonar_postgresql_data:
2

You did the opposite!

Left hand side before the colon character: host port.
Right hand side after the colon character: container port.

You can not bind a host port to more than one process, regardless whether it runs isolated in a container or native on the host. You can run multiple containers with the same container port (unless they use --network=host).

3

Oh thank you, since it’s container config, I always expect to map container to host, not host to container…
But if it’s container part, why postgres uses the 5432 instead of 65432…?

4

The port mapping does not influence on which port a service inside a container runs. It is merely a port forwarding from a host port to a private container ip port. It is usually a good idea to look at the compose specification if you are uncertain about how to configure a specific configuration element.

If you want the service inside the container to bind to a different port you will need to configure it (if possible). Some images provide environment variables to change the port, some have a config file in a volume that could be manually changed and some simply don’t allow it at all.

I often don’t even publish/map ports for a postgres container, as I don’t plan to access them with any external tools. Containers in the same (docker) network can access the database without using published ports.