⭐ Docker Volume

Image courtesy: https://miro.medium.com/v2/resize:fit:1200/1*xONk464vW-xNYxzE_HsSkw.png

✔Method 1: Creating volume using a Docker file

1. Create a dockerfile with the following contents:

   

    FROM ubuntu  #base image
    VOLUME ["/myvolume"] #creating a volume
   

2. Run the docker file and create an image

    docker build -t myimage . 
    # creates an image from the dockerfile present in the current directory, "." signifies current directory
   

3. Create and run a container from the image created:

    docker run -it --name myc1 myimage /bin/bash
   

   

   We can see a directory named "myvolume" this is the newly created volume.

4. Now lets create another container "myc2"

   Note: We have to share the volume while creating the container.

    docker run -it --name myc2 myimage --privileged=true --volumes-from myc1 ubuntu /bin/bash
    #specify new container name, image name, volume from which container, base image
   

   Output:

   

   We can see the volume "myvolume1" here. Lets create some files and then check if they are visible from "myc1" volume.

5. Running container "myc1" :

   

   We can see that the files created in container 2 are visible in container 1 and vice versa.

✔Method 2: Creating Volumes directly by commands

1. Create container with volume using the following command:

    docker run -it --name myc3 -v /volume2 ubuntu /bin/bash
    #myc3- container name
    #volume2 - volume name
   

   

2. Run the command for creating container 4 and sharing the volume created in container 3:

   

   We can see that files created in the volume are visible in container 4 as well.

✔Volumes: Host to Container

In my case I have installed Docker on EC2 instance so host is EC2 instance

Lets share volumes between container and host:

docker run -it --name host_container -v /home/ec2-user:/akshata --privileged=true ubuntu /bin/bash
# /home/ec2-user is the host directory and "akshata" - name of directory inside container

Output:

We can see files created in ec2-user directory are visible in the container and vice-versa.

Thus we have learned how to create volumes in 2 ways, through Docker file as well by the command line.

Let me know if you have any feedback, suggestions or questions. Feel free to reach out. Thank you!