Kubernetes-PV / PVC

PV (Persistent Volume)

And Volume difference

• Only network storage
• Independent Pod

PV supports mainstream storage solutions:

• GCEPersistentDisk
• AWSElasticBlockStore
• AzureFile
• AzureDisk
• FC (Fibre Channel)
• Flocker
• NFS
• iSCSI
• RBD (Ceph Block Device)
• CephFS
• Cinder (OpenStack block storage)
• Glusterfs
• VsphereVolume
• Quobyte Volumes
• HostPath (single node testing only – local storage is not supported in any way and WILL NOT WORK in a multi-node cluster)
• VMware Photon

Creating PV

apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv001
spec:
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteMany
  persistentVolumeReclaimPolicy: Recycle 
  nfs:
    path: /data/k8s/
    server: 172.16.1.131

accessModes

• ReadWriteOnce - PV in read-write mounted to a node
• ReadOnlyMany - PV in read-only mode to mount a plurality of nodes
• ReadWriteMany - PV in read-write mode to mount a plurality of nodes

Reclaim

Currently supported recovery strategy:

• Retain - allows the user to manually recovered
• Recycle - data ( "rm -rf / thevolume / *") on the Delete PV
• Delete - Delete PV

Phase

• Available - PV can be used
• Bound - PV is bound to PVC
• Released - bound PVC is deleted, it can be Reclaim
• Failed - automatic failure recovery

PVC (Persistent Volume Claim)

Create a PVC

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: myclaim
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 8Gi

Phase

Pending - waiting for an available PV
Bound - PV is bound to the PVC
Lost - bound not find PV

In the Pod

kind: Pod
apiVersion: v1
metadata:
name: mypod
spec:
containers:
- name: myfrontend
  image: dockerfile/nginx
  volumeMounts:
  - mountPath: "/var/www/html"
    name: mypd
volumes:
- name: mypd
  persistentVolumeClaim:
    claimName: myclaim