Docker volume

What is a Docker Volume?

In simple terms, a Docker Volume is a designated directory on the host machine which bypasses the Union File System, used to store and manage data in Docker. This directory becomes a reference point for Docker to save and retrieve data.

Docker Volumes offer three key benefits:

Data Persistence: Even if the container shuts down, the data remains.
Data Sharing: Multiple containers can share access to a single volume.
Performance: Volumes offer better I/O performance as compared to Docker containers.

First make a directory outside your code, and then give a fole name like — Volume and then inside this you can make a folder name where your app all data store. for example — mkdir -p volume/django_app_volume

To show docker volume in your system

docker volume ls

create docker volume

docker volume create --name <volume_name> --opt type=none --opt device=/home/ubuntu/project/volumes/django-todo-volume --opt o=bind

docker volume create --name <volume_name> --opt type=none --opt device=/home/ubuntu/project/volumes/django-todo-volume --opt o=bind

show all detail about your docker volume

docker volume inspect <volume_name>

To mount your docker volume to your system

you need to run this cmd inside where you create a volume -

docker run -d --mount source=<volume_name>,target=/data(WORKDIR) -p 8000:8000 <image_name>:latest(img_tag)

Now you can see same file and folder in your new volume creare directory.

Now go inside the container shell and create a file

docker exec -it <container_id> sh
touch <file_name>
echo "test@123" > <file_name>
exit

after comming outside the container shell you can see a new file created same as created in your container shell. now if you delete your container and after recreate a new container all data store in you new container shell.

practicle:-

1. Mount Host Project Folder to Container :-

install docker and give permission

sudo chown $USER /var/run/docker.sock

create dockerfile. and build docker image

share data between host to container without creating docker volume by directly mounting host directory to container directory.

docker run --name <contanier_name> -itd -v <host/dir>:</container/dir.> <img>:<tag>

docker exec -it <container_name or ID> bash

ex:-

docker run --name python-c -itd -v /home/hemant/devops/docker/volume:/app python:3.9-slim

docker exec -it python-c bash

docker volume create myvol

docker volume ls

docker volume instpect myvol

docker volmue remove (after detched conatainer)

docker run --name c1 -itd -v myvol:/app python

docker run --name c2 -itd -v myvol:/app1 python

docker ps docker exec -it bash