Deploying the NFS provisioner for Kubernetes

Prerequisites

Configure the variables described in the section Kubernetes Persistent Volume configuration
Install the kubectl binary on your Ansible box
Install the UCP Client bundle for the admin user
Confirm that you can connect to the cluster by running a test command, for example, kubectl get nodes

Using NFS VM for post-deployment verification

In this example, it is assumed that the relevant variables are configured as follows:

Variable	Value
nfs_provisioner_namespace	`nfsstorage`
nfs_provisioner_role	`nfs-provisioner-runner`
nfs_provisioner_serviceaccount	`nfs-provisioner`
nfs_provisioner_name	`hpe.com/nfs`
nfs_provisioner_storage_class_name	`nfs`
nfs_provisioner_server_ip	`hpe2-nfs.am2.cloudra.local`
nfs_provisioner_server_share	`/k8s`

In this instance, the server IP is set to the NFS VM that has been deployed.

Running the playbook

Once the prerequisites are satisfied, run the appropriate playbook on your Ansible node:

# cd ~/Docker-SimpliVity
# ansible-playbook -i vm_hosts playbooks/nfs-provisioner.yml --vault-password-file .vault_pass

For validation, the playbook creates a test claim and a pod, the pod writes content to a file, the pod is deleted and then the playbook checks that the contents of the file have been persisted.

        kubectl -n {{ nfs_provisioner_namespace }} apply -f /tmp/nfs-provisioner-test-claim.yml
        kubectl -n {{ nfs_provisioner_namespace }} apply -f /tmp/nfs-provisioner-test-pod.yml

        sleep 5 # need sleep here to allow pod/container to start up and write file

        ssh {{ nfs_provisioner_server_ip }} ls -R {{ nfs_provisioner_server_share }}

        echo '*** delete test-pod ***'

        kubectl -n {{ nfs_provisioner_namespace }} delete -f /tmp/nfs-provisioner-test-pod.yml

        echo '*** cat bar.txt ***'

        ssh {{ nfs_provisioner_server_ip }} "cd {{ nfs_provisioner_server_share }}/{{nfs_provisioner_namespace }}*; cat bar.txt"

        echo '*** delete test-claim ***'
        kubectl -n {{ nfs_provisioner_namespace }} delete -f /tmp/nfs-provisioner-test-claim.yml

The output of the playbook shows the various steps taking place:

        "pod/test-pod created",
        "/k8s:",
        "nfsstorage-test-claim-pvc-e6a09191-3b41-11e9-a830-0242ac11000b",
        "",
        "/k8s/nfsstorage-test-claim-pvc-e6a09191-3b41-11e9-a830-0242ac11000b:",
        "bar.txt",
        "*** delete test-pod ***",
        "pod \"test-pod\" deleted",
        "*** cat bar.txt ***",
        "hello",
        "*** delete test-claim ***",
        "persistentvolumeclaim \"test-claim\" deleted"

Running the command kubectl get sc will show the storage class named nfs:

# kubectl get sc

NAME      PROVISIONER   AGE
nfs       hpe.com/nfs   5m

The following section shows how to manually perform a similar validation test to the one done by the playbook.

Manually testing the NFS provisioner

Create a temporary file /tmp/pvc.yml for a persistent volume claim (PVC) named dynnfs-testpvc with a storage class of nfs

# cat /tmp/pvc.yml <<EOF
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: dynnfs-testpvc
  annotations:
    volume.beta.kubernetes.io/storage-class: "nfs"
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 100Mi
EOF

Create the PVC resource by running kubectl apply on this file.

# kubectl apply -f /tmp/pvc.yml

persistentvolumeclaim "dynnfs-testpvc" created

Verify that the corresponding persistent volume (PV) was created at the same time.

# kubectl get pv

NAME                                       CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS    CLAIM                    STORAGECLASS   REASON    AGE
pvc-e685a9d2-8a6f-11e8-9025-0242ac110010   100Mi      RWX            Delete           Bound     default/dynnfs-testpvc   nfs                      4s

Define a pod that will mount the persistent volume through using the persistent volume claim. The persistent volume is mounted under /tmp/foo.

cat /tmp/pod.yml <<EOF
apiVersion: apps/v1beta2
kind: Deployment
metadata:
  name: dynnfs-testpod
spec:
  selector:
    matchLabels:
      app: dynnfs-testpod
  replicas: 1
  template:
    metadata:
      labels:
        app: dynnfs-testpod
    spec:
      volumes:
      - name: pod-data
        persistentVolumeClaim:
          claimName: dynnfs-testpvc
      containers:
      - name: dynnfs-testpod
        command:
        - sh
        - -c
        - while true; do sleep 1; done
        image: radial/busyboxplus:curl
        volumeMounts:
        - mountPath: /tmp/foo
          name: pod-data
EOF

Create the pod resource by running kubectl apply on the file.

# kubectl apply -f /tmp/pod.yml

deployment.apps "dynnfs-testpod" created

Retrieve the pod ID and then execute a command in the pod to create a test file on the persistent volume. The file is named /tmp/foo/bar.txt and contains the string hello.

# pod=$(kubectl get pod | awk '/dynnfs-testpod-/ {print $1}')
# kubectl exec -it $pod -- sh -c "echo hello >/tmp/foo/bar.txt"

In this example, where the NFS VM is being used as the storage back-end, you can examine the content of the folder containing the persistent volumes. Given the values specified above, where the NFS VM is named hpe2-nfs and the nfs_provisioner_server_share is k8s, you can connect to the VM and explore the folder as follows.

# ssh hpe2-nfs ls -R /k8s
/k8s:
default-dynnfs-testpvc-pvc-e685a9d2-8a6f-11e8-9025-0242ac110010
 
/k8s/default-dynnfs-testpvc-pvc-e685a9d2-8a6f-11e8-9025-0242ac110010:
bar.txt

Examine the contents of the file to ensure that the string hello has been persisted in the file bar.txt.

# ssh hpe2-nfs cat /k8s/default-dynnfs-testpvc-pvc-e685a9d2-8a6f-11e8-9025-0242ac110010/bar.txt
hello

# Deploying the NFS provisioner for Kubernetes

# Prerequisites

# Using NFS VM for post-deployment verification

# Running the playbook

# Manually testing the NFS provisioner

Deploying the NFS provisioner for Kubernetes

Prerequisites

Using NFS VM for post-deployment verification

Running the playbook

Manually testing the NFS provisioner