Volume lifecycle basics in Rancher

Create and use persistent volumes

Create and use volumes with CSI by configuring specs you create for your storage class, PVC, and volumes.

In this example, we are using the px-csi-db storage class out of the box. Please refer to CSI Enabled Storage Classes for a list of available CSI enabled storage classes offered by Portworx.

1. Create a PersistentVolumeClaim based on the px-csi-db StorageClass:

   kind: PersistentVolumeClaim
   apiVersion: v1
   metadata:
     name: px-mysql-pvc
   spec:
     storageClassName: px-csi-db
     accessModes:
       - ReadWriteOnce
     resources:
       requests:
         storage: 2Gi

2. Create a volume by referencing the PVC you created. This example creates a MySQL deployment referencing the px-mysql-pvc PVC you created in the previous step:

   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: mysql
   spec:
     selector:
       matchLabels:
         app: mysql
     strategy:
       rollingUpdate:
         maxSurge: 1
         maxUnavailable: 1
       type: RollingUpdate
     replicas: 1
     template:
       metadata:
         labels:
           app: mysql
           version: "1"
       spec:
         containers:
         - image: mysql:5.6
           name: mysql
           env:
           - name: MYSQL_ROOT_PASSWORD
             value: password
           ports:
           - containerPort: 3306
           volumeMounts:
           - name: mysql-persistent-storage
             mountPath: /var/lib/mysql
         volumes:
         - name: mysql-persistent-storage
           persistentVolumeClaim:
             claimName: px-mysql-pvc

Create sharedv4 CSI-enabled volumes

Create sharedv4 CSI-enabled volumes by performing the following steps.

1. Create a sharedv4 PVC by creating the following shared-pvc.yaml file:

   kind: PersistentVolumeClaim
   apiVersion: v1
   metadata:
     name: px-mysql-pvc
   spec:
     storageClassName: px-csi-db
     accessModes:
       - ReadWriteMany
     resources:
       requests:
         storage: 2Gi

2. Apply the shared-pvc.yaml file:

   kubectl apply -f shared-pvc.yaml

Clone volumes with CSI

You can clone CSI-enabled volumes, duplicating both the volume and content within it.

1. Create a PVC that references the PVC you wish to clone, specifying the dataSource with the kind and name of the target PVC you wish to clone. The following spec creates a clone of the px-mysql-pvc PVC in a YAML file named clonePVC.yaml:

   kind: PersistentVolumeClaim
   apiVersion: v1
   metadata:
       name: clone-of-px-mysql-pvc
   spec:
       storageClassName: px-csi-db
       accessModes:
         - ReadWriteOnce
       resources:
         requests:
           storage: 2Gi
       dataSource:
       kind: PersistentVolumeClaim
       name: px-mysql-pvc

2. Apply the clonePVC.yaml spec to create the clone:

   kubectl apply -f clonePVC.yaml

Migrate to CSI PVCs

Currently, you cannot migrate or convert PVCs created using the native Kubernetes driver to the CSI driver. However, this is not required, and both types of PVCs can co-exist on the same cluster.