Understanding Docker volumes

One of the most common questions seen on Docker forums is how to separate data from containers. This is because any data created inside containers is lost when the container gets deleted. Using docker commit to store data inside Docker images is not a good idea. To solve this problem, Docker provides an option called data volumes. Data volumes are special shared directories that can be used by one or more Docker containers. These volumes persist even when the container is deleted. These directories are created on the host file system, usually under the /var/lib/docker/ directory.

In this recipe, we will learn to use Docker volumes, share host directories with Docker containers, and learn basic backup and restore tricks that can be used with containers.

Getting ready

Make sure that you have the Docker daemon installed and running. We will need two or more containers.

You may need sudo privileges to access the /var/lib/docker directory.

How to do it…

Follow these steps...