Volumes

Let's say we have a pod that stores some data locally on a disk. Now, if the container that's storing the data crashes and is restarted, the data will be lost. The new container will start with an empty disk space allocated. Thus, we cannot rely on containers themselves even for the temporary storage of data.

We may also have a case where one container in a pod stores some data that needs to be accessed by other containers in the same pod as well.

The Kubernetes Volume abstraction solves both of these problems. Here's a diagram showing Volumes and their interaction with physical storage and the application:

Figure 9.1: Volume as a storage abstraction for applications

As you can see from this diagram, a Volume is exposed to the applications as an abstraction, which eventually stores the data on any type of physical storage that you may be using.

The lifetime of a Kubernetes Volume is the same as that of the pod that uses it. In...