Chapter Three
Storage
How Kubernetes gives Pods durable storage — Volumes, the PersistentVolume and Claim split, dynamic provisioning by StorageClass, and the CSI that ties it to real disks.
Containers are ephemeral; their filesystem dies with them. Storage is how Kubernetes gives a Pod data that outlives the container, and it is one of the areas that bites hardest in production.
The chapter follows the abstraction from the bottom up: Volumes attached to a Pod, the PersistentVolume and Claim split that separates what you ask for from what the cluster supplies, StorageClasses that provision disks on demand, and the CSI that connects it all to real storage backends.
Topics in This Chapter
Topic 16
Volumes
Storage attached to a Pod, from scratch space to mounted ConfigMaps. The lifecycle of a Volume versus the container that uses it.
Topic 17
PersistentVolumes and Claims
The split that decouples a storage request (Claim) from the actual disk (Volume). Access modes, reclaim policies, and the binding dance.
Topic 18
StorageClasses
Dynamic provisioning by tier — fast SSD, cheap HDD, regional. How a Claim picks a class and the cluster creates the disk on demand.
Topic 19
The Container Storage Interface
The plugin standard that lets any storage vendor integrate without living in Kubernetes core. Snapshots, expansion, and topology.