Add example deployment of nfs on top of a longhorn volume

This can be used to support RWX scenarios by exposing the longhorn volume via the nfs provisioner. The nfs-provisioner we use can be found at:
https://github.com/kubernetes-incubator/external-storage/tree/master/nfs

Signed-off-by: Joshua Moody <joshua.moody@rancher.com>

examples/rwx/01-security.yaml

@@ -0,0 +1,85 @@
+apiVersion: policy/v1beta1
+kind: PodSecurityPolicy
+metadata:
+  name: longhorn-nfs-provisioner
+spec:
+  fsGroup:
+    rule: RunAsAny
+  allowedCapabilities:
+    - DAC_READ_SEARCH
+    - SYS_RESOURCE
+  runAsUser:
+    rule: RunAsAny
+  seLinux:
+    rule: RunAsAny
+  supplementalGroups:
+    rule: RunAsAny
+  volumes:
+    - configMap
+    - downwardAPI
+    - emptyDir
+    - persistentVolumeClaim
+    - secret
+    - hostPath
+---
+kind: ClusterRole
+apiVersion: rbac.authorization.k8s.io/v1
+metadata:
+  name: longhorn-nfs-provisioner
+rules:
+  - apiGroups: [""]
+    resources: ["persistentvolumes"]
+    verbs: ["get", "list", "watch", "create", "delete"]
+  - apiGroups: [""]
+    resources: ["persistentvolumeclaims"]
+    verbs: ["get", "list", "watch", "update"]
+  - apiGroups: ["storage.k8s.io"]
+    resources: ["storageclasses"]
+    verbs: ["get", "list", "watch"]
+  - apiGroups: [""]
+    resources: ["events"]
+    verbs: ["create", "update", "patch"]
+  - apiGroups: [""]
+    resources: ["services", "endpoints"]
+    verbs: ["get"]
+  - apiGroups: ["extensions"]
+    resources: ["podsecuritypolicies"]
+    resourceNames: ["nfs-provisioner"]
+    verbs: ["use"]
+---
+kind: ClusterRoleBinding
+apiVersion: rbac.authorization.k8s.io/v1
+metadata:
+  name: longhorn-nfs-provisioner
+subjects:
+  - kind: ServiceAccount
+    name: longhorn-nfs-provisioner
+    namespace: longhorn-system
+roleRef:
+  kind: ClusterRole
+  name: longhorn-nfs-provisioner
+  apiGroup: rbac.authorization.k8s.io
+---
+kind: Role
+apiVersion: rbac.authorization.k8s.io/v1
+metadata:
+  name: longhorn-nfs-provisioner
+rules:
+  - apiGroups: [""]
+    resources: ["endpoints"]
+    verbs: ["get", "list", "watch", "create", "update", "patch"]
+---
+kind: RoleBinding
+apiVersion: rbac.authorization.k8s.io/v1
+metadata:
+  name: longhorn-nfs-provisioner
+subjects:
+  - kind: ServiceAccount
+    name: longhorn-nfs-provisioner
+    namespace: longhorn-system
+roleRef:
+  kind: Role
+  name: longhorn-nfs-provisioner
+  apiGroup: rbac.authorization.k8s.io
+---
+

examples/rwx/02-longhorn-nfs-provisioner.yaml

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+apiVersion: v1
+kind: ServiceAccount
+metadata:
+  name: longhorn-nfs-provisioner
+---
+kind: Service
+apiVersion: v1
+metadata:
+  name: longhorn-nfs-provisioner
+  labels:
+    app: longhorn-nfs-provisioner
+spec:
+  ports:
+    - name: nfs
+      port: 2049
+    - name: nfs-udp
+      port: 2049
+      protocol: UDP
+    - name: nlockmgr
+      port: 32803
+    - name: nlockmgr-udp
+      port: 32803
+      protocol: UDP
+    - name: mountd
+      port: 20048
+    - name: mountd-udp
+      port: 20048
+      protocol: UDP
+    - name: rquotad
+      port: 875
+    - name: rquotad-udp
+      port: 875
+      protocol: UDP
+    - name: rpcbind
+      port: 111
+    - name: rpcbind-udp
+      port: 111
+      protocol: UDP
+    - name: statd
+      port: 662
+    - name: statd-udp
+      port: 662
+      protocol: UDP
+  selector:
+    app: longhorn-nfs-provisioner
+---
+kind: Deployment
+apiVersion: apps/v1
+metadata:
+  name: longhorn-nfs-provisioner
+spec:
+  selector:
+    matchLabels:
+      app: longhorn-nfs-provisioner
+  replicas: 1
+  strategy:
+    type: Recreate
+  template:
+    metadata:
+      labels:
+        app: longhorn-nfs-provisioner
+    spec:
+      serviceAccount: longhorn-nfs-provisioner
+      containers:
+        - name: longhorn-nfs-provisioner
+          image: quay.io/kubernetes_incubator/nfs-provisioner:latest
+          ports:
+            - name: nfs
+              containerPort: 2049
+            - name: nfs-udp
+              containerPort: 2049
+              protocol: UDP
+            - name: nlockmgr
+              containerPort: 32803
+            - name: nlockmgr-udp
+              containerPort: 32803
+              protocol: UDP
+            - name: mountd
+              containerPort: 20048
+            - name: mountd-udp
+              containerPort: 20048
+              protocol: UDP
+            - name: rquotad
+              containerPort: 875
+            - name: rquotad-udp
+              containerPort: 875
+              protocol: UDP
+            - name: rpcbind
+              containerPort: 111
+            - name: rpcbind-udp
+              containerPort: 111
+              protocol: UDP
+            - name: statd
+              containerPort: 662
+            - name: statd-udp
+              containerPort: 662
+              protocol: UDP
+          securityContext:
+            capabilities:
+              add:
+                - DAC_READ_SEARCH
+                - SYS_RESOURCE
+          args:
+            - "-provisioner=nfs.longhorn.io"
+          env:
+            - name: POD_IP
+              valueFrom:
+                fieldRef:
+                  fieldPath: status.podIP
+            - name: SERVICE_NAME
+              value: longhorn-nfs-provisioner
+            - name: POD_NAMESPACE
+              valueFrom:
+                fieldRef:
+                  fieldPath: metadata.namespace
+          imagePullPolicy: "IfNotPresent"
+          volumeMounts:
+            - name: export-volume
+              mountPath: /export
+      volumes:
+        - name: export-volume
+          persistentVolumeClaim:
+            claimName: longhorn-nfs-provisioner
+---
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: longhorn-nfs-provisioner # longhorn backing pvc
+spec:
+  storageClassName: longhorn
+  accessModes:
+    - ReadWriteOnce
+  resources:
+    requests:
+      storage: "20G" # make this 10% bigger then the workload pvc
+---
+apiVersion: storage.k8s.io/v1
+kind: StorageClass
+metadata:
+  name: longhorn-nfs # workload storage class
+provisioner: nfs.longhorn.io
+parameters:
+  mountOptions: "vers=4.1"