Lab Exercises for Storage

Exercise 0 - Setup

Prepare a cluster (Single node, kubeadm, k3s, etc)
Open browser tabs to Kubernetes Documentation, Kubernetes GitHub and Kubernetes 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 unlikely you will need to recall the nuances from memory - Kubernetes Storage Classes

Create a storageclass object named aws-ebs with the following specification:
1. The provisioner should be kubernetes.io/aws-ebs
2. The type is io1
3. The reclaimPolicy is Delete
4. allowVolumeExpansion set to false
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

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: aws-ebs
provisioner: kubernetes.io/aws-ebs
parameters:
  type: io1
reclaimPolicy: Delete
allowVolumeExpansion: false
mountOptions:
  - debug
volumeBindingMode: Immediate

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

apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv-test
spec:
  capacity:
    storage: 5Gi
  volumeMode: Filesystem
  accessModes:
    - ReadWriteOnce
  persistentVolumeReclaimPolicy: Recycle
  storageClassName: aws-ebs
  awsElasticBlockStore:
    fsType: "ext4"
    volumeID: "vol-id"

validate with:

kubectl get pv                                                                         
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

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
Create a persistentVolumeClaim to the aforementioned persistentVolume
Create a pod workload to leverage this `persistentVolumeClaim

To create the StorageClass manual apply the following:

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: manual
provisioner: kubernetes.io/no-provisioner

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
---
apiVersion: v1
kind: PersistentVolumeClaim
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