Kubernetes nfs Volume Driver for windows

A simple volume driver based on Kubernetes' Flexvolume that allows Kubernetes hosts to mount nfs volumes (nfs shares) into pods and containers.

It has been tested under Kubernetes versions:

• 1.8.x
• 1.9.x
• 1.10.x
• 1.11.x
• 1.12.x
• 1.13.x
• 1.14.x
• 1.15.x
• 1.16.x
• 1.17.x
• 1.18.x

DaemonSet Installation

When dealing with a large cluster, manually copying the driver to all hosts becomes inhuman. As proposed in Flexvolume’s documentation, the recommended driver deployment method is to have a DaemonSet install the driver cluster-wide automatically.

A Docker image mcr.microsoft.com/powershell:7.1.0-preview.5-nanoserver-1809 is available for this purpose, which can be deployed into a Kubernetes cluster using the 01-flexvolume-nfs-windows.yaml from this repository. The image is built FROM nanoserver, so the it’s essentially very small.

git clone https://github.com/xmapst/k8s-flexvolume-windows-nfs.git
cd k8s-flexvolume-windows-nfs
kubectl create -f 00-q1-win~nfs.cmd.yaml
kubectl create -f 01-flexvolume-nfs-windows.yaml

NOTE: Note: This deployment automatically installs host dependencies and does not need to be completed manually on all hosts.

If you need to tweak or customize the installation, you can modify the 01-flexvolume-nfs-windows.yaml directly.

Installing is a one time job. So, once you have verified that it’s completed, the DaemonSet can be safely removed.

kubectl delete -f 01-flexvolume-nfs-windows.yaml
kubectl delete -f 00-q1-win~nfs.cmd.yaml

The Volume Plugin Directory

As of today with Kubernetes v1.16, the kubelet’s default directory for volume plugins is /usr/libexec/kubernetes/kubelet-plugins/volume/exec/. This could be different if your installation changed this directory using the --volume-plugin-dir parameter.

Please, review the kubelet command line parameters (namely --volume-plugin-dir) and make sure it matches the directory where the driver will be installed.

You can modify 01-flexvolume-nfs-windows.yaml and change the field spec.template.spec.volumes.hostPath.path to the path used by your Kubernetes installation.

Customizing the Vendor/Driver name

By default, the driver installation path is $KUBELET_PLUGIN_DIRECTORY/q1autoops-win/nfs.cmd.

For some installations, you may need to change the vendor + driver name. You can define the installed vendor name/directory by adjusting the 01-flexvolume-nfs-windows.yaml plugin directory.

## snippet ##

      containers:
        - image: mcr.microsoft.com/powershell:7.1.0-preview.5-nanoserver-1809
          env:
          - name: DRIVER
            value: q1autoops-win
          command: 
          - pwsh.exe
          args:
          - /Command
          - mkdir -Force c:\host\${DRIVER}~nfs.cmd;
          - cp -Force c:\kubelet-plugins\flexvolume.ps1 c:\host\${DRIVER}~nfs.cmd;
          - cp -Force c:\kubelet-plugins\nfs.cmd c:\host\${DRIVER}~nfs.cmd;
          - cp -Force c:\kubelet-plugins\nfs.ps1 c:\host\${DRIVER}~nfs.cmd;
          - cat c:\kubelet-plugins\Readme.md;
          - while ($true) {start-sleep -s 3600}

## snippet ##

The example above will install the driver in the path $KUBELET_PLUGIN_DIRECTORY/q1autoops-win~nfs.cmd/nfs.cmd. For the most part, changig the DRIVER variable should be enough to make your installation unique to your needs.

Example of Deployment

The following is an example of Deployment that uses the volume driver.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nfs
  namespace: nfs
  labels:
    app: nfs
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nfs
  template:
    metadata:
      labels:
        app: nfs
    spec:
      nodeSelector:
        beta.kubernetes.io/os: windows
      tolerations:
      - key: "os"
        operator: "Equal"
        value: "windows"
        effect: "NoSchedule"
      containers:
      - name: nfs
        image: mcr.microsoft.com/powershell:7.1.0-preview.5-nanoserver-1809
        imagePullPolicy: IfNotPresent
        command: ["ppwsh.exe"]
        args: ["/Command", "ping", "-t", "127.0.0.1", ">>", "/d/test.txt"]
        volumeMounts:
        - name: nfs-volume
          mountPath: /d
      imagePullSecrets:
      - name: shenzhen-regcred
      volumes:
      - name: nfs-volume
        flexVolume:
          driver: "q1-win/nfs.cmd"
          options:
            # source can be in any of the following formats
            # \\servername\share\path  (\'s will need to be escaped)
            # nfs://servername/share/path
            # //servername/share/path
            source: "nfs://xxx-xxx.cn-shenzhen.nas.aliyuncs.com/!"