Docker Volumes

Managing volumes through Docker CLI

Tested Infrastructure

Pre-requisite

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

docker volume commands

Creating Volume called demo

docker volume create demo

Listing Docker Volumes

docker volume ls

Inspecting “demo” Docker Volume

docker inspect demo

Removing the “demo” Docker Volume

docker volume rm demo

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

Tested Infrastructure

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