Mounting a volume inside docker container

Docker volumes provide a way to create shared storage that persists beyond the lifecycle of individual containers. When you have multiple containers that need to share common files, mounting a volume allows all containers to access and modify the same data from a centralized location.

This approach is particularly useful in microservices architectures where different containers handle different parts of an application but need to share configuration files, logs, or data files. By mounting a volume to multiple containers, you create a shared filesystem that remains available even when individual containers are stopped or removed.

Creating and Managing Docker Volumes

First, check existing volumes on your system −

sudo docker volume ls

Create a new named volume −

sudo docker volume create tutorialspoint

Inspect the volume details to see its configuration −

sudo docker volume inspect tutorialspoint

Mounting Volume to First Container

Create and run the first container with the mounted volume −

sudo docker run -it -v tutorialspoint:/sharedVol --name container01 ubuntu

The -v flag mounts the tutorialspoint volume to the /sharedVol directory inside the container. The -it flags provide an interactive terminal session.

Inside the container, create a test file in the shared volume −

ls
cd /sharedVol
echo "Welcome to docker tutorialspoint" > dockertutorials.txt
ls
exit

Accessing Volume from Second Container

Create another container and mount the same volume −

sudo docker run -it -v tutorialspoint:/sharedVol --name container02 ubuntu

Verify that the file created in the first container is accessible −

cd sharedVol
ls
cat dockertutorials.txt
exit

Volume Persistence After Container Removal

Remove both containers to demonstrate volume persistence −

sudo docker rm -f container01 container02
sudo docker ps -a

Create a new container and mount the same volume −

sudo docker run -it -v tutorialspoint:/sharedVol --name container03 ubuntu

The shared file still exists, demonstrating volume persistence −

ls
cd sharedVol
ls
cat dockertutorials.txt

Key Benefits

Conclusion

Docker volumes provide persistent, shared storage for containerized applications. By mounting volumes to multiple containers, you can create a shared filesystem that persists beyond individual container lifecycles, making it ideal for data sharing and backup scenarios in distributed applications.