Examples

For reference, this page provides examples of Kubernetes resources that use Longhorn storage.

• Block volume
• CSI persistent volume
• Deployment
• Pod with PersistentVolumeClaim
• Restore to file
• Simple Pod
• Simple PersistentVolumeClaim
• StatefulSet
• StorageClass

Block Volume

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: longhorn-block-vol
spec:
  accessModes:
    - ReadWriteOnce
  volumeMode: Block
  storageClassName: longhorn
  resources:
    requests:
      storage: 2Gi
---
apiVersion: v1
kind: Pod
metadata:
  name: block-volume-test
  namespace: default
spec:
  containers:
    - name: block-volume-test
      image: nginx:stable-alpine
      imagePullPolicy: IfNotPresent
      volumeDevices:
        - devicePath: /dev/longhorn/testblk
          name: block-vol
      ports:
        - containerPort: 80
  volumes:
    - name: block-vol
      persistentVolumeClaim:
        claimName: longhorn-block-vol

CSI Persistent Volume

apiVersion: v1
kind: PersistentVolume
metadata:
  name: longhorn-vol-pv
spec:
  capacity:
    storage: 2Gi
  volumeMode: Filesystem
  accessModes:
    - ReadWriteOnce
  persistentVolumeReclaimPolicy: Delete
  storageClassName: longhorn
  csi:
    driver: driver.longhorn.io
    fsType: ext4
    volumeAttributes:
      numberOfReplicas: '3'
      staleReplicaTimeout: '2880'
    volumeHandle: existing-longhorn-volume
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: longhorn-vol-pvc
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 2Gi
  volumeName: longhorn-vol-pv
  storageClassName: longhorn
---
apiVersion: v1
kind: Pod
metadata:
  name: volume-pv-test
  namespace: default
spec:
  restartPolicy: Always
  containers:
  - name: volume-pv-test
    image: nginx:stable-alpine
    imagePullPolicy: IfNotPresent
    livenessProbe:
      exec:
        command:
          - ls
          - /data/lost+found
      initialDelaySeconds: 5
      periodSeconds: 5
    volumeMounts:
    - name: vol
      mountPath: /data
    ports:
    - containerPort: 80
  volumes:
  - name: vol
    persistentVolumeClaim:
      claimName: longhorn-vol-pvc

Deployment

apiVersion: v1
kind: Service
metadata:
  name: mysql
  labels:
    app: mysql
spec:
  ports:
    - port: 3306
  selector:
    app: mysql
  clusterIP: None
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: mysql-pvc
spec:
  accessModes:
    - ReadWriteOnce
  storageClassName: longhorn
  resources:
    requests:
      storage: 2Gi
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: mysql
  labels:
    app: mysql
spec:
  selector:
    matchLabels:
      app: mysql # has to match .spec.template.metadata.labels
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: mysql
    spec:
      restartPolicy: Always
      containers:
      - image: mysql:5.6
        name: mysql
        livenessProbe:
          exec:
            command:
              - ls
              - /var/lib/mysql/lost+found
          initialDelaySeconds: 5
          periodSeconds: 5
        env:
        - name: MYSQL_ROOT_PASSWORD
          value: changeme
        ports:
        - containerPort: 3306
          name: mysql
        volumeMounts:
        - name: mysql-volume
          mountPath: /var/lib/mysql
        env:
        - name: MYSQL_ROOT_PASSWORD
          value: "rancher"
      volumes:
      - name: mysql-volume
        persistentVolumeClaim:
          claimName: mysql-pvc

Pod with PersistentVolumeClaim

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: longhorn-volv-pvc
spec:
  accessModes:
    - ReadWriteOnce
  storageClassName: longhorn
  resources:
    requests:
      storage: 2Gi
---
apiVersion: v1
kind: Pod
metadata:
  name: volume-test
  namespace: default
spec:
  restartPolicy: Always
  containers:
  - name: volume-test
    image: nginx:stable-alpine
    imagePullPolicy: IfNotPresent
    livenessProbe:
      exec:
        command:
          - ls
          - /data/lost+found
      initialDelaySeconds: 5
      periodSeconds: 5
    volumeMounts:
    - name: volv
      mountPath: /data
    ports:
    - containerPort: 80
  volumes:
  - name: volv
    persistentVolumeClaim:
      claimName: longhorn-volv-pvc

Restore to File

For more information about restoring to file, refer to this section.

apiVersion: v1
kind: Pod
metadata:
  name: restore-to-file
  namespace: longhorn-system
spec:
  nodeName: <NODE_NAME>
  containers:
  - name: restore-to-file
    command:
    # set restore-to-file arguments here
    - /bin/sh
    - -c
    - longhorn backup restore-to-file
      '<BACKUP_URL>'
      --output-file '/tmp/restore/<OUTPUT_FILE>'
      --output-format <OUTPUT_FORMAT>
    # the version of longhorn engine should be v0.4.1 or higher
    image: longhorn/longhorn-engine:v0.4.1
    imagePullPolicy: IfNotPresent
    securityContext:
      privileged: true
    volumeMounts:
    - name: disk-directory
      mountPath: /tmp/restore  # the argument <output-file> should be in this directory
    env:
    # set Backup Target Credential Secret here.
    - name: AWS_ACCESS_KEY_ID
      valueFrom:
        secretKeyRef:
          name: <S3_SECRET_NAME>
          key: AWS_ACCESS_KEY_ID
    - name: AWS_SECRET_ACCESS_KEY
      valueFrom:
        secretKeyRef:
          name: <S3_SECRET_NAME>
          key: AWS_SECRET_ACCESS_KEY
    - name: AWS_ENDPOINTS
      valueFrom:
        secretKeyRef:
          name: <S3_SECRET_NAME>
          key: AWS_ENDPOINTS
  volumes:
    # the output file can be found on this host path
    - name: disk-directory
      hostPath:
        path: /tmp/restore
  restartPolicy: Never

Simple Pod

apiVersion: v1
kind: Pod
metadata:
  name: longhorn-simple-pod
  namespace: default
spec:
  restartPolicy: Always
  containers:
    - name: volume-test
      image: nginx:stable-alpine
      imagePullPolicy: IfNotPresent
      livenessProbe:
        exec:
          command:
            - ls
            - /data/lost+found
        initialDelaySeconds: 5
        periodSeconds: 5
      volumeMounts:
        - name: volv
          mountPath: /data
      ports:
        - containerPort: 80
  volumes:
    - name: volv
      persistentVolumeClaim:
        claimName: longhorn-simple-pvc

Simple PersistentVolumeClaim

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: longhorn-simple-pvc
spec:
  accessModes:
    - ReadWriteOnce
  storageClassName: longhorn
  resources:
    requests:
      storage: 1Gi

StatefulSet

apiVersion: v1
kind: Service
metadata:
  name: nginx
  labels:
    app: nginx
spec:
  ports:
  - port: 80
    name: web
  selector:
    app: nginx
  type: NodePort
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: web
spec:
  selector:
    matchLabels:
      app: nginx # has to match .spec.template.metadata.labels
  serviceName: "nginx"
  replicas: 2 # by default is 1
  template:
    metadata:
      labels:
        app: nginx # has to match .spec.selector.matchLabels
    spec:
      restartPolicy: Always
      terminationGracePeriodSeconds: 10
      containers:
      - name: nginx
        image: k8s.gcr.io/nginx-slim:0.8
        livenessProbe:
          exec:
            command:
              - ls
              - /usr/share/nginx/html/lost+found
          initialDelaySeconds: 5
          periodSeconds: 5
        ports:
        - containerPort: 80
          name: web
        volumeMounts:
        - name: www
          mountPath: /usr/share/nginx/html
  volumeClaimTemplates:
  - metadata:
      name: www
    spec:
      accessModes: [ "ReadWriteOnce" ]
      storageClassName: "longhorn"
      resources:
        requests:
          storage: 1Gi

StorageClass

kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: longhorn
provisioner: driver.longhorn.io
allowVolumeExpansion: true
reclaimPolicy: Delete
volumeBindingMode: Immediate
parameters:
  numberOfReplicas: "3"
  staleReplicaTimeout: "2880" # 48 hours in minutes
  fromBackup: ""
  fsType: "ext4"
  #  backingImage: "bi-test"
  #  backingImageDataSourceType: "download"
  #  backingImageDataSourceParameters: '{"url": "https://backing-image-example.s3-region.amazonaws.com/test-backing-image"}'
  #  backingImageChecksum: "SHA512 checksum of the backing image"
  #  diskSelector: "ssd,fast"
  #  nodeSelector: "storage,fast"
  #  recurringJobSelector: '[
  #   {
  #     "name":"snap",
  #     "isGroup":true,
  #   },
  #   {
  #     "name":"backup",
  #     "isGroup":false,
  #   }
  #  ]'

Note that Longhorn supports automatic remount only for the workload pod that is managed by a controller (e.g. deployment, statefulset, daemonset, etc…). See here for details.