Room 25

STORAGECLASSES

The Provisioner’s Workshop

StorageClasses enable dynamic provisioning - claim storage and it’s created automatically.
No need to pre-create PVs. The StorageClass handles it.

📜 Mission Briefing

List existing StorageClasses: kubectl get sc.
Examine the default StorageClass in your Kind cluster.
Create a PVC that uses the default StorageClass - storage is provisioned dynamically.
Apply dynamic-pvc.yaml and dynamic-pod.yaml.
Write a file in the dynamically provisioned volume, then read it back.
The password is stored in the StorageClass annotation: storclass.

Key Commands

Command	Purpose
`kubectl get sc`	List StorageClasses
`kubectl describe sc NAME`	StorageClass details
`kubectl get pvc`	See bound PVCs
`kubectl get pv`	See dynamically created PVs

How StorageClasses Work

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: fast-storage
  annotations:
    storageclass.kubernetes.io/is-default-class: "true"
provisioner: rancher.io/local-path    # Kind uses local-path-provisioner
reclaimPolicy: Delete
volumeBindingMode: WaitForFirstConsumer
allowVolumeExpansion: true

# PVC with StorageClass (dynamic provisioning)
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: dynamic-claim
spec:
  accessModes:
    - ReadWriteOnce
  storageClassName: standard    # Name of StorageClass
  resources:
    requests:
      storage: 1Gi
# PV is automatically created when PVC is created!

# Common provisioners:
# kubernetes.io/aws-ebs         → AWS EBS volumes
# kubernetes.io/gce-pd          → Google Persistent Disk
# kubernetes.io/azure-disk      → Azure Managed Disk
# rancher.io/local-path         → Kind local storage
# kubernetes.io/no-provisioner  → Manual (no dynamic)

# Dynamic provisioning flow:
# 1. Create StorageClass with provisioner
# 2. Create PVC referencing the StorageClass
# 3. Provisioner automatically creates a PV
# 4. PVC binds to the new PV
# 5. Pod mounts the PVC

# Set default StorageClass
kubectl patch storageclass standard \
  -p '{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"true"}}}'

Hints

Hint 1

kubectl get sc
kubectl describe sc standard

Hint 2

Apply and check:

kubectl apply -f dynamic-pvc.yaml
kubectl apply -f dynamic-pod.yaml
kubectl get pv,pvc

Hint 3

The password is storclass.

🔓 Unlock Room 26

openssl enc -aes-256-cbc -d -a -pbkdf2 \
        -in ../room_26/README             \
        -out ../room_26/README.txt        \
        -pass pass:PASSWORD
cat ../room_26/README.txt