
Continuous Delivery with Docker and Jenkins, 3rd Edition
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Imagine that you would like to run a database as a container. You can start such a container and enter data. Where is it stored? What happens when you stop the container or remove it? You can start a new one, but the database will be empty again. Unless it's your testing environment, you'd expect to have your data persisted permanently.
A Docker volume is the Docker host's directory mounted inside the container. It allows the container to write to the host's filesystem as if it were writing to its own. The mechanism is presented in the following diagram:
Figure 2.10 – Using a Docker volume
Docker volumes enable the persistence and sharing of a container's data. Volumes also clearly separate the processing from the data. Let's start with the following example:
-v <host_path>:<container_path>
option and then connect to...