version: '2'

services:

  db1:
    image: "mongo:3.4"
    command: 'mongod --replSet "databank0"'
    networks:
      db:
        ipv4_address: 172.23.42.3

  db2:
    image: "mongo:3.4"
    command: 'mongod --replSet "databank0"'
    networks:
      db:
        ipv4_address: 172.23.42.4

  db3:
    image: "mongo:3.4"
    command: 'mongod --replSet "databank0"'
    networks:
      db:
        ipv4_address: 172.23.42.2

  db4:
    image: "mongo:3.4"
    networks:
      db:
        ipv4_address: 172.23.42.5

networks:
  db:
    driver: bridge
    ipam:
      driver: default
      config:
      - subnet: 172.23.42.0/24
        gateway: 172.23.42.1