Creating Volume Mount from docker run command & sharing same Volume Mounts among multiple containers

Tested Infrastructure

Platform Number of Instance Reading Time
Play with Docker 1 5 min

Pre-requisite

  • Create an account with DockerHub
  • Open PWD Platform on your browser
  • Click on “Add New Node”

Volumes can be shared across containers

Preparations

  • Clean your docker host using the commands :
$ docker rm -f $(docker ps -a -q)

$ docker volume rm $(docker volume ls -q)

Task

  1. The Task for this lab is to create a volume, call it my_volume.

  2. you should than run a simple an thin container and attach a volume to it. use the image selaworkshops/busybox:latest and use any name to the mounted volume directory (e.g : data)

  3. change something in the volume folder , e.g : add a file with some content.

  4. create a second volume mounted to the same volume , make sure the file you created in step 3 exists !

Instructions

  • Display existing volumes: 
    $ docker volume ls
  • Create a new volume: 
    $ docker volume create my-volume
  • Inspect the new volume to find the mountpoint (volume location): 
    $ docker volume inspect my-volume

    [
 {
     "CreatedAt": "2018-06-13T20:36:15Z",
     "Driver": "local",
     "Labels": {},
     "Mountpoint": "/var/lib/docker/volumes/my-volume/_data",
     "Name": "my-volume",
     "Options": {},
     "Scope": "local"
 }
]
  • Let’s run a container and mount the created volume to the root: 
    $ docker run -it -v my-volume:/data --name my-container selaworkshops/busybox:latest
  • Create a new file under /data: 
    $ cd /data
$ echo "hello" > hello.txt
$ ls
  • Open other terminal instance and run other container with the same volume: 
    $ docker run -it -v my-volume:/data --name my-container-2 selaworkshops/busybox:latest
  • Inspect the /data folder (the created file will be there): 
    $ cd data
$ ls
  • Exit from both containers and delete them: 
    $ exit
$ docker rm -f my-container my-container-2
  • Ensure the containers were deleted 
    $ docker ps -a
  • Run a new container attaching the created volume: 
    $ docker run -it -v my-volume:/data --name new-container selaworkshops/busybox:latest
  • Inspect the /data folder (the created file will be there): 
    $ cd data
$ ls
  • Exit from the container and delete it: 
    $ exit
$ docker rm -f new-container

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