Docker-compose Networks and Volumes

Using docker-compose yaml file, we can create multiple networks and volume in an application.

The below code shows how to create networks using YAML file 

version: '3'
services:
  web:
    build:
      context: .
      dockerfile: Dockerfile
      args:
        - PYTHON_VERSION=3.4-alpine
    image: coolgourav147/python-redis
    ports:
      - "5000:5000"
    networks:
      - appnetwork
  redis:
    image: "redis:alpine"
    volumes:
      - myredisdata:/data
    networks:
      - appnetwork

  redis2:
    image: "redis:alpine"
    volumes:
      - myredisdata2:/data
    networks:
      - appnetwork2
networks:
  appnetwork:
  appnetwork2:

volumes:
  myredisdata:
  myredisdata2:

We have defined 3 containers inside services, each container is using network and volume. At the end network is the property/field which will create 2 networks appnetwork and appnetwork2,likewise, volumes are the property to create volume inside the container.Users can attach the network with any container if and only if it has been created in YAML file.

Before running the docker-compose up -d command ,there are no networks and new volumes created. 

gaurav@learning-ocean:~/python_redis$ docker container ls
CONTAINER ID   IMAGE     COMMAND   CREATED   STATUS    PORTS     NAMES
gaurav@learning-ocean:~/python_redis$ docker volume ls
DRIVER    VOLUME NAME
gaurav@learning-ocean:~/python_redis$ docker network ls
NETWORK ID     NAME      DRIVER    SCOPE
0022a9f511fe   bridge    bridge    local
3a33f83c3663   host      host      local
e4ebd601732c   none      null      local

let run docker-compose up

[email protected]:~$ docker-compose up -d
Creating network "docker-volumes_appnetwork" with the default driver
Creating network "docker-volumes_default" with the default driver
Building web
Sending build context to Docker daemon  5.632kB

let check network, volume and containers again

[email protected]:~$ docker container ls
CONTAINER ID   IMAGE                        COMMAND                  CREATED         STATUS         PORTS                    NAMES
d0df46f4f293   redis:alpine                 "docker-entrypoint.s…"   9 seconds ago   Up 7 seconds   6379/tcp                 docker-networks_redis_1
11f7d05376d2   coolgourav147/python-redis   "python app.py"          9 seconds ago   Up 6 seconds   0.0.0.0:5000->5000/tcp   docker-networks_web_1
5f9d87371ad6   redis:alpine                 "docker-entrypoint.s…"   9 seconds ago   Up 6 seconds   6379/tcp                 docker-networks_redis2_1
[email protected]:$ docker volume ls
DRIVER    VOLUME NAME
local     docker-networks_myredisdata
local     docker-networks_myredisdata2
[email protected]:~$ docker network ls
NETWORK ID     NAME                          DRIVER    SCOPE
0022a9f511fe   bridge                        bridge    local
4dd17646884a   docker-networks_appnetwork    bridge    local
d124edf4aa4c   docker-networks_appnetwork2   bridge    local
3a33f83c3663   host                          host      local
e4ebd601732c   none                          null      local
[email protected]:~$