## ZFS-LocalPV Volume Resize We can resize the volume by updating the PVC yaml to the desired size and apply it. The ZFS Driver will take care of updating the quota in case of dataset. If we are using a Zvol and have mounted it as ext2/3/4 or xfs file system, the driver will take care of expanding the volume via reize2fs/xfs_growfs binaries. For resize, storageclass that provisions the pvc must support resize. We should have allowVolumeExpansion as true in storageclass ``` $ cat sc.yaml apiVersion: storage.k8s.io/v1 kind: StorageClass metadata: name: openebs-zfspv allowVolumeExpansion: true parameters: poolname: "zfspv-pool" provisioner: zfs.csi.openebs.io $ kubectl apply -f sc.yaml storageclass.storage.k8s.io/openebs-zfspv created ``` Create the PVC using the above storage class ``` $ cat pvc.yaml kind: PersistentVolumeClaim apiVersion: v1 metadata: name: csi-zfspv spec: storageClassName: openebs-zfspv accessModes: - ReadWriteOnce resources: requests: storage: 4Gi $ kubectl apply -f pvc.yaml persistentvolumeclaim/csi-zfspv created ``` OpenEBS ZFS driver supports Online Volume expansion, which means that we can expand the volume even if volume is being used by the application and we also don't need to restart the application to use the expanded volume, the ZFS Driver will take care of making the space availbale to it. Please note that file system expansion does not happen until a Application pod references the resized volume, so if no pods referencing the volume are running, file system expansion will not happen. Deploy the application using the PVC. Here is sample yaml for the application : ``` $ cat fio.yaml apiVersion: apps/v1 kind: Deployment metadata: name: fio labels: name: fio spec: replicas: 1 selector: matchLabels: name: fio template: metadata: labels: name: fio spec: containers: - resources: name: perfrunner image: ljishen/fio imagePullPolicy: IfNotPresent command: ["/bin/sh"] args: ["-c", "while true ;do sleep 50; done"] volumeMounts: - mountPath: /datadir name: fio-vol volumes: - name: fio-vol persistentVolumeClaim: claimName: csi-zfspv $ kubectl apply -f fio.yaml deployment.apps/fio created $ kubectl get po NAME READY STATUS RESTARTS AGE fio-5b7884bc7b-4mssk 1/1 Running 0 40s ``` Check the current PVC status ``` $ kubectl get pvc NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE csi-zfspv Bound pvc-966b0749-5dea-442f-a584-013cf5d25201 4Gi RWO openebs-zfspv 85s ``` Exec into the application pod and check the size ``` # df -h /datadir/ Filesystem Size Used Available Use% Mounted on /dev/zd0 3.9G 16.0M 3.8G 0% /datadir ``` Deploy the application using the PVC which supports volume expansion. Once the application pod is deployed, we will expand the PVC to 5Gi from 4Gi. Just edit the PVC yaml and update the size to 5Gi and apply it :- ``` $ cat pvc.yaml kind: PersistentVolumeClaim apiVersion: v1 metadata: name: csi-zfspv spec: storageClassName: openebs-zfspv accessModes: - ReadWriteOnce resources: requests: storage: 5Gi ``` Apply the above yaml which will resize the volume ``` $ kubectl apply -f pvc.yaml persistentvolumeclaim/csi-zfspv configured ``` Check the PVC yaml ```yaml $ kubectl get pvc csi-zfspv -oyaml apiVersion: v1 kind: PersistentVolumeClaim metadata: annotations: kubectl.kubernetes.io/last-applied-configuration: | {"apiVersion":"v1","kind":"PersistentVolumeClaim","metadata":{"annotations":{},"name":"csi-zfspv","namespace":"default"},"spec":{"accessModes":["ReadWriteOnce"],"r esources":{"requests":{"storage":"5Gi"}},"storageClassName":"openebs-zfspv"}} pv.kubernetes.io/bind-completed: "yes" pv.kubernetes.io/bound-by-controller: "yes" volume.beta.kubernetes.io/storage-provisioner: zfs.csi.openebs.io creationTimestamp: "2020-03-06T06:40:08Z" finalizers: - kubernetes.io/pvc-protection name: csi-zfspv namespace: default resourceVersion: "2547405" selfLink: /api/v1/namespaces/default/persistentvolumeclaims/csi-zfspv uid: 966b0749-5dea-442f-a584-013cf5d25201 spec: accessModes: - ReadWriteOnce resources: requests: storage: 5Gi storageClassName: openebs-zfspv volumeMode: Filesystem volumeName: pvc-966b0749-5dea-442f-a584-013cf5d25201 status: accessModes: - ReadWriteOnce capacity: storage: 4Gi conditions: - lastProbeTime: null lastTransitionTime: "2020-03-06T06:41:22Z" message: Waiting for user to (re-)start a pod to finish file system resize of volume on node. status: "True" type: FileSystemResizePending phase: Bound ``` Here you see in the message that it is waiting on FileSystemResizePending. The resize request will go to the node where appliccation pod is running. The ZFS driver node agent will resize the filesytem for the application. Keep checking the PVC yaml for FileSystemResizePending to go away, once PVC is resized, the yaml will look like this :- ```yaml $ kubectl get pvc csi-zfspv -oyaml apiVersion: v1 kind: PersistentVolumeClaim metadata: annotations: kubectl.kubernetes.io/last-applied-configuration: | {"apiVersion":"v1","kind":"PersistentVolumeClaim","metadata":{"annotations":{},"name":"csi-zfspv","namespace":"default"},"spec":{"accessModes":["ReadWriteOnce"],"resources":{"requests":{"storage":"5Gi"}},"storageClassName":"openebs-zfspv"}} pv.kubernetes.io/bind-completed: "yes" pv.kubernetes.io/bound-by-controller: "yes" volume.beta.kubernetes.io/storage-provisioner: zfs.csi.openebs.io creationTimestamp: "2020-03-06T06:40:08Z" finalizers: - kubernetes.io/pvc-protection name: csi-zfspv namespace: default resourceVersion: "2547449" selfLink: /api/v1/namespaces/default/persistentvolumeclaims/csi-zfspv uid: 966b0749-5dea-442f-a584-013cf5d25201 spec: accessModes: - ReadWriteOnce resources: requests: storage: 5Gi storageClassName: openebs-zfspv volumeMode: Filesystem volumeName: pvc-966b0749-5dea-442f-a584-013cf5d25201 status: accessModes: - ReadWriteOnce capacity: storage: 5Gi phase: Bound ``` ``` $ kubectl get pvc NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE csi-zfspv Bound pvc-675bf643-c744-4a30-984c-5b2c53c51f14 5Gi RWO openebs-zfspv 28m ``` Also, we can exec into the application pod and verify the same :- ``` # df -h /datadir/ Filesystem Size Used Available Use% Mounted on /dev/zd0 4.9G 16.0M 4.8G 0% /datadir ``` As we can see the volume mount point /datadir is showing that it has been resized.