Kubernetes Storage: PVC, PV and StorageClass — Challenge

The goal#

Achieve the same outcome as Kubernetes Storage: PVC, PV and StorageClass, from an empty starting point, without the steps.

A container's filesystem dies with the container. Most workloads do not care; a database very much does.

This lab shows the difference concretely, then walks into the access mode that stops a Deployment scaling — which is one of the more confusing first encounters with Kubernetes storage.

What must be true when you are done#

• Data written into a container is gone after the Pod is deleted — demonstrated, not assumed.
• The same data survives a Pod deletion once a PVC is mounted.
• You can explain why a 3-replica Deployment with one ReadWriteOnce PVC leaves Pods Pending.
• You can state what happens to the underlying disk when the PVC is deleted, for your StorageClass.

Rules#

• Do not open the guided lab until you are finished, or until the same problem has held you up for 20 minutes.
• Documentation is allowed. In the job it is the first thing you open.
• Verify every criterion with a command whose output you can read.

If you get stuck#

1. What did you expect, exactly?
2. What happened instead — the error text, not a paraphrase?
3. Which layer is that error from?
4. What is the smallest command that proves the layer below is fine?