Chapter 4. Persistent storage and shared state with volumes

At this point in the book, you’ve installed and run a few programs. You’ve seen a few toy examples but haven’t run anything that resembles the real world. The difference between the examples in the first three chapters and the real world is that in the real world, programs work with data. This chapter introduces Docker volumes and strategies that you’ll use to manage data with containers.

Consider what it might look like to run a database program inside a container. You could package the software with the image, and when you start the container it might initialize an empty database. When programs connect to the database and enter data, where is that data stored? Is it in a file inside the container? What happens to that data when you stop the container or remove it? How would you move your data if you wanted to upgrade the database program?

4.1. Introducing volumes

4.2. Volume types

4.3. Sharing volumes

4.4. The managed volume life cycle

4.5. Advanced container patterns with volumes

4.6. Summary