Volumes for persistent data in Docker - Mini Project: Build & Apply

Volumes for persistent data

📖 Scenario: You are setting up a Docker container to run a simple web server. You want to make sure that the data created by the server is saved even if the container stops or is removed. This is important because you want to keep your website files safe and not lose them.

🎯 Goal: Learn how to create and use Docker volumes to store persistent data outside the container. You will create a volume, attach it to a container, and verify that data is saved persistently.

📋 What You'll Learn

Create a Docker volume named webdata

Run a Docker container named mywebserver using the nginx image

Mount the webdata volume to the container's /usr/share/nginx/html directory

Verify that the volume is used by checking the container's volume configuration

💡 Why This Matters

🌍 Real World

Docker volumes are used to save data generated by containers so it is not lost when containers stop or are deleted. This is important for databases, web servers, and any service that needs to keep files or data.

💼 Career

Understanding Docker volumes is essential for DevOps roles because managing persistent data in containers is a common task in deploying and maintaining applications.

1

Create a Docker volume

Create a Docker volume called webdata using the docker volume create command.

Docker

# Create the Docker volume named webdata
# Your code here

Need a hint?

Use the command docker volume create webdata to create the volume.

2

Run a container with the volume attached

Run a Docker container named mywebserver using the nginx image. Attach the webdata volume to the container's /usr/share/nginx/html directory using the --mount option.

Docker

docker volume create webdata
# Run the container named mywebserver with the webdata volume mounted
# Your code here

Need a hint?

Use docker run -d --name mywebserver --mount source=webdata,target=/usr/share/nginx/html nginx to start the container.

3

Check the volume usage in the container

Use the docker inspect command on the container mywebserver to check that the volume webdata is mounted at /usr/share/nginx/html.

Docker

docker volume create webdata
docker run -d --name mywebserver --mount source=webdata,target=/usr/share/nginx/html nginx
# Inspect the container to verify the volume mount
# Your code here

Need a hint?

Run docker inspect mywebserver and look for the Mounts section showing webdata mounted at /usr/share/nginx/html.

4

Show the volume mount details from inspect output

Run docker inspect mywebserver and print only the Mounts section to confirm the volume webdata is attached to /usr/share/nginx/html.

Docker

docker volume create webdata
docker run -d --name mywebserver --mount source=webdata,target=/usr/share/nginx/html nginx
docker inspect mywebserver
# Print the Mounts section from the inspect output
# Your code here

Need a hint?

Use docker inspect mywebserver --format '{{json .Mounts}}' to print the mounts in JSON format.