Can't run multiple mongodb docker container with same shared volume

Question

I want to run two mongo docker containers with docker compose. The mongo containers have same shared volumes with the docker host. When I ran it with docker compose, only one mongo container is working meanwhile the other is shutting down because it said

DBPathInUse: Unable to lock the lock file: /data/db/mongod.lock (Unknown error). Another mongod instance is already running on the /data/db directory, terminating

This is my docker compose file

version: '3'
services:
  frontend:
    image: fernandomaxwell/frontend
    ports:
     - "3007:3007"
    networks:
      main:
      database_frontend:

  backend:
    image: fernandomaxwell/backend
    ports:
     - "2007:2007"
    networks:
      main:
      database_backend:

  mongo_backend:
    image: mongo
    volumes:
     - "/var/lib/mongodb:/data/db"
    ports:
     - "27017:27017"
    networks:
      database_backend:

  mongo_frontend:
    image: mongo
    volumes:
     - "/var/lib/mongodb:/data/db"
    ports:
     - "27018:27017"
    networks:
      database_frontend:

networks:
  main:
  database_backend:
  database_frontend:

Any idea to solve this?

Answer 1

The problem is here:

The mongo containers have same shared volumes with the docker host

You cannot run two mongo instances on the same data-directory. It would lead to data corruption and strange problems, so mongo-db explicitly prohibits doing that (see also this question here)

Why do you want to do this? Normally you would provide two different volumes for your mongo instances like this:

version: '3'
services:
  frontend:
    image: fernandomaxwell/frontend
    ports:
     - "3007:3007"
    networks:
      main:
      database_frontend:

  backend:
    image: fernandomaxwell/backend
    ports:
     - "2007:2007"
    networks:
      main:
      database_backend:

  mongo_backend:
    image: mongo
    volumes:
     - "/var/lib/mongodb-back:/data/db"
    ports:
     - "27017:27017"
    networks:
      database_backend:

  mongo_frontend:
    image: mongo
    volumes:
     - "/var/lib/mongodb-front:/data/db"
    ports:
     - "27018:27017"
    networks:
      database_frontend:

networks:
  main:
  database_backend:
  database_frontend:

Additionally you should consider to use named volumes, instead of host-paths. Doing that you don't need to take care of creating the directories on the host before starting the compose-file. To use named volumes just change the volume declaration from "/var/lib/mongodb-back:/data/db" to "mongodb-back:/data/db"