Introducing Docker storage drivers and volumes

Docker containers are ephemeral workloads. That means whatever data you store on your container filesystem gets wiped out once the container is gone. The data lives on a disk during the container life cycle, but it does not persist beyond it. Pragmatically speaking, most applications in the real world are stateful. They need to store data beyond the container life cycle, and they want data to persist.

So, how do we go along with that? Docker provides several ways you can store data. By default, all data is stored on the writable container layer, which is ephemeral. The writable container layer interacts with the host filesystem via a storage driver. Because of the abstraction, writing files to the container layer is slower than writing directly to the host filesystem.

To solve that problem and also provide persistent storage, Docker provides volumes, bind mounts, and tmpfs. With them, you can interact directly with the host filesystem...