MicroK8s : Storage を有効にする2020/08/04

MicroK8s ビルトインの Storage を有効にする場合は以下のように設定します。

[1]	プライマリーノードで、ビルトイン Storage を有効にします。

root@dlp:~#

microk8s enable storage

Enabling default storage class
deployment.apps/hostpath-provisioner created
storageclass.storage.k8s.io/microk8s-hostpath created
serviceaccount/microk8s-hostpath created
clusterrole.rbac.authorization.k8s.io/microk8s-hostpath created
clusterrolebinding.rbac.authorization.k8s.io/microk8s-hostpath created
Storage will be available soon

# [hostpath-provisioner] pod が起動する

root@dlp:~#

microk8s kubectl get pods -A

NAMESPACE     NAME                                        READY   STATUS    RESTARTS   AGE
kube-system   coredns-588fd544bf-g9frb                    1/1     Running   2          21h
kube-system   dashboard-metrics-scraper-59f5574d4-67tjr   1/1     Running   2          21h
kube-system   hostpath-provisioner-75fdc8fccd-2w95n       1/1     Running   0          13s
kube-system   kubernetes-dashboard-6d97855997-p5hzj       1/1     Running   2          21h
kube-system   metrics-server-c65c9d66-zzdl6               1/1     Running   2          21h

[2]	PVC (Persistent Volume Claim) オブジェクトを定義しての、Pod からのストレージ利用例です。

root@dlp:~#

vi my-pvc.yml

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  # 任意の PVC 名
  name: my-pvc
spec:
  # アクセスモード:
  # - ReadWriteMany (複数ノード RW)
  # - ReadWriteOnce (単一ノード RW)
  # - ReadOnlyMany (複数ノード R)
  accessModes:
    - ReadWriteOnce
  # microk8s-hostpath を指定
  storageClassName: microk8s-hostpath
  resources:
    requests:
      # 利用したいストレージのサイズ
      storage: 1Gi

root@dlp:~#

microk8s kubectl create -f my-pvc.yml

persistentvolumeclaim/my-pvc created

root@dlp:~#

microk8s kubectl get pv

NAME                                       CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM            STORAGECLASS        REASON   AGE
pvc-93bec44d-d46d-477f-b553-2da40f712849   1Gi        RWO            Delete           Bound    default/my-pvc   microk8s-hostpath            50s

root@dlp:~#

microk8s kubectl get pvc

NAME     STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS        AGE
my-pvc   Bound    pvc-93bec44d-d46d-477f-b553-2da40f712849   1Gi        RWO            microk8s-hostpath   53s

# 例として nginx pod 作成

root@dlp:~#

vi nginx-mypv.yml

apiVersion: v1
kind: Pod
metadata:
  name: nginx-mypv
  labels:
    name: nginx-mypv
spec:
  containers:
    - name: nginx-mypv
      image: fedora/nginx
      ports:
        - name: web
          containerPort: 80
      volumeMounts:
        - name: my-persistent-volume
          mountPath: /usr/share/nginx/html
  volumes:
    - name: my-persistent-volume
      persistentVolumeClaim:
        # 事前に定義した PVC 名を指定
        claimName: my-pvc

root@dlp:~#

microk8s kubectl create -f nginx-mypv.yml

pod/nginx-mypv created

root@dlp:~#

microk8s kubectl get pods -o wide

NAME         READY   STATUS    RESTARTS   AGE   IP           NODE            NOMINATED NODE   READINESS GATES
nginx-mypv   1/1     Running   0          34m   10.1.21.18   dlp.srv.world   <none>           <none>

# PVC の Path 確認

root@dlp:~#

microk8s kubectl describe -n kube-system pod/hostpath-provisioner-75fdc8fccd-2w95n | grep PV_DIR

      PV_DIR:     /var/snap/microk8s/common/default-storage

root@dlp:~#

microk8s kubectl describe pvc/my-pvc | grep ^Volume:

Volume:        pvc-93bec44d-d46d-477f-b553-2da40f712849

# テストページ作成

root@dlp:~#

echo "Hello MicroK8s" > /var/snap/microk8s/common/default-storage/default-my-pvc-pvc-93bec44d-d46d-477f-b553-2da40f712849/index.html

# アクセスして確認

root@dlp:~#

curl 10.1.21.18

Hello MicroK8s