docker compose up Error "Ports are not available"

Question

I am trying to run my docker container with each service on different ports, but I keep receiving an error specific to port 8000 being accessed by multiple ports when I am only using port 8000 for one service.

Everything works fine when I remove the qcluster service, but I don't understand why when its configured for port 8001 and not 80000

Here's the error message:

Error response from daemon: Ports are not available: exposing port TCP 0.0.0.0:8000 -> 0.0.0.0:0: listen tcp 0.0.0.0:8000: bind: Only one usage of each socket address (protocol/network address/port) is normally permitted.

and here is the compose.yaml file:

services:
  db:
    image: postgres
    volumes:
      - ./data/db:/var/lib/postgresql/data
    environment:
      - POSTGRES_PASSWORD=***********
      - SECRET_KEY=************************
      - DB_HOST=*******************
      - DB_PWD=****************
      - DB_CERT=****************
  web:
    build:
      context: app
    command: python manage.py runserver 0.0.0.0:8000
    ports:
      - '8000:8000'
    expose:
      - '8000'
    environment:
      - SECRET_KEY=**********************
      - DB_HOST=db.***********
      - DB_PWD=***************
      - DB_CERT=*************
    depends_on:
      - db
  qcluster:
    build:
      context: app
    command: python manage.py qcluster
    volumes:
      - .:/code
    ports:
      - "8000:8001"
    depends_on:
      - db

Answer 1

Seems that you have another container/service listening on port 8000.

Run docker container ls and check if there are containers already listening on 8000. If so, just kill that container and try again.

If there are no running container, maybe there's another service that is listening on that port. To identify it, run

lsof -i TCP:8000 | grep LISTEN

to obtain its PID (a number that represent the ID of that process). Then, kill it using

kill -9 YOUR_PID_HERE