cka_storage.md

Lab Exercises for Storage

Exercise 0 - Setup

• Prepare a cluster (Single node, kubeadm, k3s, etc)
• Open browser tabs to https://kubernetes.io/docs/, https://github.com/kubernetes/ and https://kubernetes.io/blog/ (these are permitted as per the current guidelines)

Exercise 1 - Understand storage classes, persistent volumes

Note: Leverage the docs to help you. It's unlikey you will need to recall the nuances from memory - https://kubernetes.io/docs/concepts/storage/storage-classes/

1. Create a storageclass object named aws-ebs with the following specification:
   1. The provisioner should be kubernetes.io/azure-disk
   2. The reclaimPolicy is Delete
   3. allowVolumeExpansion set to false
2. Create a persistentvolume based on this storage class
   1. Note, it will not initialize unless AWS integration is configured, but the objective is to get the YAML correct.

Answer

Apply the following YAML to create the Storage Class

kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: managed-premium-new
provisioner: kubernetes.io/azure-disk
reclaimPolicy: Delete
parameters:
  storageaccounttype: Premium_LRS
  kind: Managed

Apply the following YAML to create a Persistent Volume based on the Storage Class

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: azure-managed-disk-new
spec:
  accessModes:
  - ReadWriteOnce
  storageClassName: managed-premium-new
  resources:
    requests:
      storage: 5Gi

validate with:

kubectl get pvc                                                                         
NAME      CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM   STORAGECLASS   REASON   AGE
pv-test   5Gi        RWO            Recycle          Available           aws-ebs                 5

Exercise 2 - Know how to configure applications with persistent storage

In this exercise, we will not be using storageClass objects

1. Create a persistentVolume object of type hostPath with the following parameters:
   1. 1GB Capacity
   2. Path on the host is /tmp
   3. storageClassName is Manual
   4. accessModes is ReadWriteOnce
2. Create a persistentVolumeClaim to the aforementioned persistentVolume
3. Create a pod workload to leverage this `persistentVolumeClaim

Answer

apiVersion: v1
kind: PersistentVolume
metadata:
 name: pv-hostpath-1gb
spec:
 capacity:
   storage: 1Gi
 volumeMode: Filesystem
 accessModes:
   - ReadWriteOnce
 persistentVolumeReclaimPolicy: Recycle
 storageClassName: manual
 hostPath:
   path: /tmp
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
 name: pvc-hostpath-claim
spec:
 accessModes:
   - ReadWriteOnce
 volumeMode: Filesystem
 resources:
   requests:
     storage: 512Mi
 storageClassName: manual
---
apiVersion: v1
kind: Pod
metadata:
 name: pod-with-pvc
spec:
 volumes:
   - name: myvol
     persistentVolumeClaim:
      claimName: pvc-hostpath-claim
 containers:
 - name: busybox
   image: busybox
   args:
   - sleep
   - "1000000"
   volumeMounts:
     - mountPath: "/mnt/readonly"
       name: myvol

Validate with:

kubectl get po,pv,pvc
NAME               READY   STATUS    RESTARTS   AGE
pod/pod-with-pvc   1/1     Running   0          2m7s

NAME                               CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM                        STORAGECLASS   REASON   AGE
persistentvolume/pv-hostpath-1gb   1Gi        RWO            Recycle          Bound    default/pvc-hostpath-claim   manual                  2m7s

NAME                                       STATUS   VOLUME            CAPACITY   ACCESS MODES   STORAGECLASS   AGE
persistentvolumeclaim/pvc-hostpath-claim   Bound    pv-hostpath-1gb   1Gi        RWO            manual         2m7s