Managing storage classes

Managing storage classes

Creating a storage class

kubectl create namespace nfs-provisioner

kubectl config set-context --current --namespace nfs-provisioner

Context "kubernetes-admin@desotech" modified.

kubectl apply -f \
	https://raw.githubusercontent.com/desotech-it/DSK201-public/master/common-storageclass.yaml

Check the ip of NFS already provisioned:

cat ~/listaip.txt

Use the NFS’s IP to control the exported NFS:

showmount -e 10.10.95.100

You should see a NFS export with this path: /nfs/provisioner

Now create a new file and change the IP with the NFS Server’s IP and the export path of the NFS Server:

vi /home/student/nfs-pod-provisioner.yaml

File: /home/student/nfs-pod-provisioner.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: nfs-pod-provisioner
  name: nfs-pod-provisioner
  namespace: nfs-provisioner
spec:
  replicas: 1
  strategy:
    type: Recreate
  selector:
    matchLabels:
      app: nfs-pod-provisioner
  template:
    metadata:
      labels:
        app: nfs-pod-provisioner
    spec:
      serviceAccountName: nfs-pod-provisioner-sa # name of service account created in rbac.yaml
      containers:
      - image: quay.io/external_storage/nfs-client-provisioner:latest
        name: nfs-client-provisioner
        resources: {}
        volumeMounts:
          - name: nfs-provisioner-v
            mountPath: /persistentvolumes
        env:
          - name: PROVISIONER_NAME # do not change
            value: nfs-deso-provisioner # SAME AS PROVISONER NAME VALUE IN STORAGECLASS
          - name: NFS_SERVER # do not change
            value: 10.10.XX.100 # Change with Ip of the NFS SERVER
          - name: NFS_PATH # do not change
            value: /nfs/provisioner  # path to nfs directory setup
      volumes:
       - name: nfs-provisioner-v # same as volumemouts name
         nfs:
           server: 10.10.XX.100 # Change with Ip of the NFS SERVER
           path: /nfs/provisioner

kubectl apply -f nfs-pod-provisioner.yaml

deployment.apps/nfs-pod-provisioner created

vi /home/student/storageclass.yaml

File: /home/student/storageclass.yaml

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: nfs-storageclass # IMPORTANT pvc needs to mention this name
provisioner: nfs-deso-provisioner # name can be anything
parameters:
  archiveOnDelete: "false"
  volumeBindingMode: WaitForFirstConsumer

kubectl apply -f storageclass.yaml

storageclass.storage.k8s.io/nfs-storageclass created

kubectl get sc

NAME               PROVISIONER            RECLAIMPOLICY   VOLUMEBINDINGMODE   ALLOWVOLUMEEXPANSION   AGE
nfs-storageclass   nfs-deso-provisioner   Delete          Immediate           false                  16s

kubectl create ns test-storageclass

namespace/test-storageclass created

kubectl config set-context --current --namespace test-storageclass

Context "kubernetes-admin@desotech" modified.

vi /home/student/pvc01.yaml

File: /home/student/pvc01.yaml

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc01
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 1G
  storageClassName: nfs-storageclass

Create this PVC:

kubectl apply -f pvc01.yaml

persistentvolumeclaim/pvc01 created

kubectl get pv,pvc

NAME                                                        CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM                     STORAGECLASS       REASON   AGE
persistentvolume/pvc-e62ff4ba-ac2f-4edc-b2a7-b571856739bb   1G         RWO            Delete           Bound    test-storageclass/pvc01   nfs-storageclass            16s

NAME                          STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS       AGE
persistentvolumeclaim/pvc01   Bound    pvc-e62ff4ba-ac2f-4edc-b2a7-b571856739bb   1G         RWO            nfs-storageclass   17s

kubectl  get sc

NAME               PROVISIONER            RECLAIMPOLICY   VOLUMEBINDINGMODE   ALLOWVOLUMEEXPANSION   AGE
nfs-storageclass   nfs-deso-provisioner   Delete          Immediate           false                  9m13s

vi /home/student/pvc02.yaml

File: /home/student/pvc02.yaml

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc02
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 1G

Create this PVC:

kubectl apply -f pvc02.yaml

 persistentvolumeclaim/pvc02 created

kubectl get pvc

NAME    STATUS    VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS       AGE
pvc01   Bound     pvc-e62ff4ba-ac2f-4edc-b2a7-b571856739bb   1G         RWO            nfs-storageclass   2m58s
pvc02   Pending                                                                                           18s

Setting a default storage class

Kubernetes v1.6 added the ability to set a default storage class. This is the storage class that will be used to provision a PV if a user does not specify one in a PVC.

You can define a default storage class by setting the annotation storageclass.kubernetes.io/is-default-class to true in the storage class definition. According to the specification, any other value or absence of the annotation is interpreted as false.

It is possible to configure an existing storage class to be the default storage class by using the following command:

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

kubectl get sc

NAME                         PROVISIONER            RECLAIMPOLICY   VOLUMEBINDINGMODE   ALLOWVOLUMEEXPANSION   AGE
nfs-storageclass (default)   nfs-deso-provisioner   Delete          Immediate           false                  11m

kubectl delete -f pvc02.yaml

persistentvolumeclaim "pvc02" deleted

kubectl apply -f pvc02.yaml

persistentvolumeclaim/pvc02 created

kubectl  get pvc

NAME    STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS       AGE
pvc01   Bound    pvc-e62ff4ba-ac2f-4edc-b2a7-b571856739bb   1G         RWO            nfs-storageclass   4m42s
pvc02   Bound    pvc-b9af9093-a3d6-46d4-9e84-72bc86c77c1a   1G         RWO            nfs-storageclass   3s

Clean up

kubectl  delete ns test-storageclass

namespace "test-storageclass" deleted

kubectl config set-context --current --namespace default

Context "kubernetes-admin@desotech" modified.