Mastering Kubernetes - Second Edition

Volume

Local storage on the pod is ephemeral and goes away with the pod. Sometimes that's all you need, if the goal is just to exchange data between containers of the node, but sometimes it's important for the data to outlive the pod, or it's necessary to share data between pods. The volume concept supports that need. Note that, while Docker has a volume concept too, it is quite limited (although it is getting more powerful). Kubernetes uses its own separate volumes. Kubernetes also supports additional container types, such as rkt, so it can't rely on Docker volumes, even in principle.

There are many volume types. Kubernetes currently directly supports many volume types, but the the modern approach for extending Kubernetes with more volume ...