...
Dynamic Volumes using the NFS Provisioner
Coming soon!
See https://github.com/kubernetes-incubator/external-storage/tree/master/nfs
In a slightly more complex example, we can actually have Kubernetes provision volumes dynamically for us from an NFS export.
- Clone the repo above
- Locate the nfs/deploy/kubernetes subfolder
- Edit deployment.yaml (e.g. change nodeSelector, change mount path/config)
- kubectl create -f auth/serviceaccount.yaml -f auth/clusterrole.yaml -f auth/clusterrolebinding.yaml
- kubectl create -f class.yaml -f deployment.yaml
Congratulations! Wasn't that easy?
Testing it Out
A simple test case for consuming a dynamic PVC can be found below:
- kubectl create -f claim.yaml
- kubectl create -f write_pod.yaml
Expected output:
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ubuntu@mltf-master:~/external-storage/nfs/deploy/kubernetes$ kubectl get pvc,pv
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
persistentvolumeclaim/nfs Bound pvc-253140dc-6dc2-11e8-9b58-fa163eace583 1Mi RWX example-nfs 15m
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
persistentvolume/pvc-253140dc-6dc2-11e8-9b58-fa163eace583 1Mi RWX Delete Bound default/nfs example-nfs 15m
# Look up the UID of our PVC (we will need this to find it on disk later)
ubuntu@mltf-master:~/external-storage/nfs/deploy/kubernetes$ kubectl get pvc -o yaml
apiVersion: v1
items:
- apiVersion: v1
kind: PersistentVolumeClaim
metadata:
annotations:
control-plane.alpha.kubernetes.io/leader: '{"holderIdentity":"c9839a10-6dc1-11e8-b790-0a580af40112","leaseDurationSeconds":15,"acquireTime":"2018-06-11T21:55:25Z","renewTime":"2018-06-11T21:55:27Z","leaderTransitions":0}'
... ... ... ... ... ... ... ... ... ...
volume.beta.kubernetes.io/storage-class: example-nfs
volume.beta.kubernetes.io/storage-provisioner: example.com/nfs
... ... ... ... ... ... ... ... ... ...
uid: 253140dc-6dc2-11e8-9b58-fa163eace583
spec:
... ... ... ... ... ... ... ... ... ...
requests:
storage: 1Mi
volumeName: pvc-253140dc-6dc2-11e8-9b58-fa163eace583
status:
... ... ... ... ... ... ... ... ... ...
# Wait for the write-pod to finish executing
ubuntu@mltf-master:~/external-storage/nfs/deploy/kubernetes$ kubectl get pods
NAME READY STATUS RESTARTS AGE NODE
mongo-k2pqv 1/1 Running 0 1h mltf-worker0
ndslabs-apiserver-pd62v 2/2 Running 0 1h mltf-storage1
ndslabs-etcd-ppsdv 1/1 Running 0 23m mltf-worker0
ndslabs-webui-qx4fb 1/1 Running 0 1h mltf-storage1
nfs-provisioner-7f78fcc699-vjr8d 1/1 Running 0 6m mltf-storage0
nfs-server-wc8h6 1/1 Running 0 5h mltf-storage0
web 1/1 Running 0 2h mltf-storage0
web2 1/1 Running 0 4h mltf-storage0
web3 1/1 Running 0 4h mltf-worker0
write-pod 0/1 Completed 0 2m mltf-storage1 <-------
# SSH into "storage0" (this is where the nfs-provisioner is currently running)
ubuntu@mltf-master:~/external-storage/nfs/deploy/kubernetes$ ssh 192.168.0.3
Welcome to Ubuntu 16.04.4 LTS (GNU/Linux 4.4.0-127-generic x86_64)
* Documentation: https://help.ubuntu.com
* Management: https://landscape.canonical.com
* Support: https://ubuntu.com/advantage
Get cloud support with Ubuntu Advantage Cloud Guest:
http://www.ubuntu.com/business/services/cloud
14 packages can be updated.
7 updates are security updates.
Last login: Mon Jun 11 21:55:53 2018 from 192.168.0.6
# Locate the subdirectory of the nfs-provisioner on our OpenStack volume for shared storage
ubuntu@mltf-storage0:~$ ls -al /data
total 32
drwxr-xr-x 5 root root 4096 Jun 11 21:51 .
drwxr-xr-x 26 root root 4096 Jun 11 21:19 ..
drwx------ 2 root root 16384 Jun 8 22:46 lost+found
drwxr-xr-x 4 root root 4096 Jun 11 20:52 nfs
drwxr-xr-x 3 root root 4096 Jun 11 21:55 nfs-provisioner
# Locate the subdirectory of our specific PVC (NOTE: this will match the "volume name" and UID of the PVC we looked up earlier)
ubuntu@mltf-storage0:~$ ls -al /data/nfs-provisioner/
total 36
drwxr-xr-x 3 root root 4096 Jun 11 21:55 .
drwxr-xr-x 5 root root 4096 Jun 11 21:51 ..
-rw-r--r-- 1 root root 14791 Jun 11 21:55 ganesha.log
-rw------- 1 root root 36 Jun 11 21:51 nfs-provisioner.identity
drwxrwsrwx 2 root root 4096 Jun 11 21:56 pvc-253140dc-6dc2-11e8-9b58-fa163eace583
-rw------- 1 root root 902 Jun 11 21:55 vfs.conf
# Verify the contents of the PVC
ubuntu@mltf-storage0:~$ ls -al /data/nfs-provisioner/pvc-253140dc-6dc2-11e8-9b58-fa163eace583/
total 8
drwxrwsrwx 2 root root 4096 Jun 11 21:56 .
drwxr-xr-x 3 root root 4096 Jun 11 21:55 ..
-rw-r--r-- 1 root root 0 Jun 11 21:56 SUCCESS <------
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