Persistent storage using hostPath

    OKD supports hostPath mounting for development and testing on a single-node cluster.

    In a production cluster, you would not use hostPath. Instead, a cluster administrator would provision a network resource, such as a GCE Persistent Disk volume, an NFS share, or an Amazon EBS volume. Network resources support the use of storage classes to set up dynamic provisioning.

    A hostPath volume must be provisioned statically.

    A pod that uses a hostPath volume must be referenced by manual (static) provisioning.

    Procedure

    1. Define the persistent volume (PV). Create a file, pv.yaml, with the PersistentVolume object definition:

      1.   apiVersion: v1
      2.   kind: PersistentVolume
      3.   metadata:
      4.     name: task-pv-volume (1)
      5.     labels:
      6.       type: local
      7.   spec:
      8.     storageClassName: manual (2)
      9.     capacity:
      10.       storage: 5Gi
      11.     accessModes:
      12.       - ReadWriteOnce (3)
      13.     persistentVolumeReclaimPolicy: Retain

    2. Create the PV from the file:

      1. apiVersion: v1
      2. kind: PersistentVolumeClaim
      3. metadata:
      4.   name: task-pvc-volume
      5. spec:
      6.   accessModes:
      7.     - ReadWriteOnce
      8.   resources:
      9.     requests:
      10.       storage: 1Gi
      11.   storageClassName: manual

    4. Create the PVC from the file:

    After the persistent volume claim has been created, it can be used inside by an application. The following example demonstrates mounting this share inside of a pod.

    Prerequisites

    • A persistent volume claim exists that is mapped to the underlying hostPath share.

    Procedure

      1. kind: Pod
      3.   name: pod-name (1)
      4. spec:
      5.   containers:
      6.     ...
      7.     securityContext:
      8.       privileged: true (2)
      9.     volumeMounts:
      10.     - mountPath: /data (3)
      11.       name: hostpath-privileged
      12.   ...
      13.   securityContext: {}
      14.   volumes:
      15.     - name: hostpath-privileged
      16.       persistentVolumeClaim:
      17.         claimName: task-pvc-volume (4)