chore(doc): adding README for ZFSPV

Signed-off-by: Pawan <pawan@mayadata.io>

README.md

@@ -1,2 +1,156 @@
-# zfs-localpv
-CSI driver for provisioning Local PVs backed by ZFS and more. 
+# OpenEBS ZFS CSI Driver
+
+CSI driver for provisioning Local PVs backed by ZFS and more.
+
+## Project Status
+
+This project is under active development and considered to be in Alpha state.
+The current implementation only supports provisioning and de-provisioning of ZFS Volumes.
+
+## Usage
+
+### Prerequisites
+
+Before installing ZFS driver please make sure your Kubernetes Cluster
+must meet the following prerequisites:
+
+1. all the nodes must have zfs utils installed
+2. ZPOOL has been setup for provisioning the volume
+3. You have access to install RBAC components into kube-system namespace.
+   The OpenEBS ZFS driver components are installed in kube-system namespace
+   to allow them to be flagged as system critical components.
+
+### Setup
+
+All the node should have zfsutils-linux installed. We should go to the
+each node of the cluster and install zfs utils
+```
+$ apt-get install zfsutils-linux
+```
+
+### Installation
+
+OpenEBS ZFS driver components can be installed by running the
+following command.
+
+```
+kubectl apply -f https://raw.githubusercontent.com/openebs/zfs-localpv/master/deploy/zfs-operator.yaml
+```
+
+Verify that the ZFS driver Components are installed and running using below command :
+
+
+```
+$ kubectl get pods -n kube-system -l role=openebs-zfs
+```
+
+Depending on number of nodes, you will see one zfs-controller pod and zfs-node daemonset running
+on the nodes.
+
+```
+NAME                       READY   STATUS    RESTARTS   AGE
+openebs-zfs-controller-0   4/4     Running   0          5h28m
+openebs-zfs-node-4d94n     2/2     Running   0          5h28m
+openebs-zfs-node-gssh8     2/2     Running   0          5h28m
+openebs-zfs-node-twmx8     2/2     Running   0          5h28m
+
+```
+
+Once ZFS driver is installed we can provision a volume.
+
+
+### Deployment
+
+1. create a Storage class
+
+```yaml
+apiVersion: storage.k8s.io/v1
+kind: StorageClass
+metadata:
+  name: openebs-zfspv
+parameters:
+  blocksize: "4k"
+  compression: "off"
+  dedup: "off"
+  thinprovision: "no"
+  poolname: "zfspv-pool"
+provisioner: openebs.io/zfs
+```
+
+The storage class contains the volume paramaters like blocksize, compression, dedup and thinprovision. You can select what are all
+parameters you want. The above yaml shows the default values in case paramenters are not provided or wrong value has been provided.
+The *poolname* is the must argument. There must be a ZPOOL running on the node with the name given in this storage class.
+
+Here we have to give the provisioner as "openebs.io/zfs" which is the provisioner name of the ZFS driver.
+
+2. create a PVC
+
+```yaml
+kind: PersistentVolumeClaim
+apiVersion: v1
+metadata:
+  name: csi-zfspv
+spec:
+  storageClassName: openebs-zfspv
+  accessModes:
+    - ReadWriteOnce
+  resources:
+    requests:
+      storage: 4Gi
+```
+
+Create a PVC using the storage class created with the openebs.io/zfs provisioner.
+
+3. Deploy the application using this PVC
+
+```yaml
+apiVersion: v1
+kind: Pod
+metadata:
+  name: fio
+spec:
+  affinity:
+    nodeAffinity:
+      requiredDuringSchedulingIgnoredDuringExecution:
+        nodeSelectorTerms:
+        - matchExpressions:
+          - key: kubernetes.io/hostname
+            operator: In
+            values:
+            - gke-user-zfspv-default-pool-fb71317f-rgcm
+  restartPolicy: Never
+  containers:
+  - name: perfrunner
+    image: openebs/tests-fio
+    command: ["/bin/bash"]
+    args: ["-c", "while true ;do sleep 50; done"]
+    volumeMounts:
+       - mountPath: /datadir
+         name: fio-vol
+    tty: true
+  volumes:
+  - name: fio-vol
+    persistentVolumeClaim:
+      claimName: csi-zfspv
+```
+
+Here in alpha version of the ZFS driver we have to make use of node selector or node affinity
+to make the application pod stick to the node as the application pod should not move to the
+other node because the data will be there on one node only.
+
+After the deployment of the application we can go to the node and see that a zfs volume has been
+created in the pool mentioned in the storage class and application is using that volume for writting
+the data. This is in effect working like waitforFirstConsumer so the actual ZFS volume will be create
+when application is deployed to the node.
+
+```
+$ zfs list
+NAME                                                  USED  AVAIL  REFER  MOUNTPOINT
+zfspv-pool                                           4.25G  92.1G    96K  /zfspv-pool
+zfspv-pool/pvc-f52058b7-da1c-11e9-80e0-42010a800fcd  4.25G  96.4G  5.69M  -
+```
+
+4. for deprovisioning the volume we can delete the application which is using
+   the volume and then we can go ahead and delete the pv, as part of deletion of
+   pv this volume will also be deleted from the ZFS pool and data will be free.
+