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CSI Driver

To facilitate quick integration with Curvine in cloud-native environments, Curvine provides CSI driver support. Your Pod containers can access Curvine through PV (Persistent Volume) without requiring application modifications, enabling the use of Curvine's caching capabilities.

The Curvine CSI driver follows the standard CSI specification and includes:

  • CSI Controller, deployed in Deployment mode or Statefulset mode
  • CSI Node Plugin, deployed in DaemonSet mode

Deployment scripts are located in the curvine-csi/deploy directory. Execute:

kubectl create -f curvine-csi/deploy
warning

Currently, the curvine-csi depends on a fuse version that only supports cluster configuration file connection method. Therefore, in deploy/configmap.yaml, you need to fill in the master_addrs option with the real curvine master address.

This is a temporary solution. If you want to try it out, you can test it. We are working on supporting custom parameters for fuse, and various configuration parameters for connecting to the cluster will be customized through storageclass or pv attributes. This will be released soon, stay tuned!

The CSI driver is still in rapid iteration. If you encounter issues during use, welcome to submit an issue 😄!

After successful deployment, you will see the following pods:

NAME                     READY   STATUS    RESTARTS   AGE
curvine-controller-0     4/4     Running   0          4h32m
curvine-csi-node-jbvmt   3/3     Running   0          4h32m

csi-arch

warning

The Curvine CSI driver depends on fuse, which is established by the CSI node plugin. Since CSI driver upgrades will interrupt the fuse service, proceed with caution.

Deploy CSI​

First, deploy the CSI driver in the k8s cluster and ensure that the CSI node plugin is running properly.

PVC+Static PV​

You can manually create a static PV and bind the PVC to the static PV. Example:

---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: curvine-pv
  labels:
    type: curvine
spec:
  storageClassName: curvine-sc
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteOnce
  persistentVolumeReclaimPolicy: Delete
  csi:
    driver: curvine
    volumeHandle: curvine-volume-1
    volumeAttributes:
      curvinePath: "/"
      type: "Directory" # Using Directory type requires that the path must already exist
note

The following fields are required:

  • volumeAttributes.curvinePath must be /, as currently Curvine fuse only supports mounting the root path
  • volumeAttributes.type as Directory indicates the path already exists. DirectoryOrCreate indicates the path will be automatically created if it doesn't exist

PVC+Dynamic PV​

To use dynamic PV, you need to define a StorageClass first.

StorageClass example:

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: curvine-sc
provisioner: curvine
reclaimPolicy: Delete
volumeBindingMode: Immediate
allowVolumeExpansion: true
parameters:
  curvinePath: "/"
  type: "DirectoryOrCreate" #"DirectoryOrCreate" or "Directory"

PVC example:

---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: curvine-pvc
spec:
  storageClassName: curvine-sc
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 5Gi

After creating the PVC, a PV will be automatically created with the status Bound, as shown below:

$ kubectl get pvc
NAME          STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   VOLUMEATTRIBUTESCLASS   AGE
curvine-pvc   Bound    pvc-fce87a49-828f-43d2-8360-7901b0b5f886   5Gi        RWO            curvine-sc     <unset>                 16s

Creating a Pod​

Mount the Curvine volume to a pod. Example:

apiVersion: v1
kind: Pod
metadata:
  name: curvine-csi-pod
  labels:
    app: curvine-csi-pod
spec:
  containers:
    - name: web-server
      image: nginx
      ports:
        - containerPort: 80
          name: "http-server"
      volumeMounts:
        - mountPath: "/usr/share/nginx/html"
          name: curvine-storage
  volumes:
    - name: curvine-storage
      persistentVolumeClaim:
        claimName: curvine-pvc

Verification​

On a cluster with Curvine running, you can manually create a file in the root path, such as 'index.html'. You can use the fuse feature; by default, the fuse mounted by Curvine is at the /curvine-fuse path.

$ ls /curvine-fuse
index.html

Check in the pod:

$ kubectl exec curvine-test-pod -n default -- /usr/bin/cat /usr/share/nginx/html/index.html
<html>
        hello curvine csi
</html>