Create a Docker volume and use it to persist data for a MySQL container.

Question

Create a Docker volume and use it to persist data for a MySQL container. Verify that the data persists even after the container is removed. Try creating a test db.

Solution

There are ways to persist the data between the container and the host. (Using binded mount and unbinded mount )

Step 1: Create a Docker Volume

docker volume create mysql_data

This creates a volume named mysql_data where MySQL will store its data.

Step 2: Run a MySQL Container with the Volume

Now, run a MySQL container and attach the volume to it. Replace your_password with your own secure password for the root user.

docker run --name mysql-container -e MYSQL_ROOT_PASSWORD=your_password -v mysql_data:/var/lib/mysql -d mysql:latest

• --name mysql-container: Names the container.

• -e MYSQL_ROOT_PASSWORD=your_password: Sets the root password for MySQL.

• -v mysql_data:/var/lib/mysql: Mounts the mysql_data volume to /var/lib/mysql, where MySQL stores its data.

• -d mysql:latest: Runs the latest version of MySQL in detached mode.

Step 3: Access the MySQL Container and Create a Test Database

To interact with the MySQL container, you can use the following command to get into the MySQL shell

docker exec -it mysql-container mysql -u root -p

Once inside the MySQL shell, enter your root password, and then create a test database

CREATE DATABASE test_db;
SHOW DATABASES;

You should see test_db in the list of databases.

Step 4: Remove the MySQL Container

Now, remove the container

docker rm -f mysql-container

This will remove the MySQL container, but the volume will still exist.

Step 5: Re-run the MySQL Container with the Same Volume

To verify that the data persists, re-run the container with the same volume

docker run --name mysql-container -e MYSQL_ROOT_PASSWORD=your_password -v mysql_data:/var/lib/mysql -d mysql:latest

Step 6: Check if the Data Persists

After the container is running, access the MySQL shell again

docker exec -it mysql-container mysql -u root -p

Once in the shell, check for the existence of `test_db`

SHOW DATABASES;

If the test_db database appears in the list, this confirms that the data persisted even after the container was removed.