PLEASE NOTE: This document applies to the HEAD of the source tree
If you are using a released version of Kubernetes, you should
refer to the docs that go with that version.
The latest release of this document can be found
[here](http://releases.k8s.io/release-1.1/examples/nfs/README.md).
Documentation for other releases can be found at
[releases.k8s.io](http://releases.k8s.io).
--
# Example of NFS volume
See [nfs-web-rc.yaml](nfs-web-rc.yaml) for a quick example of how to use an NFS
volume claim in a replication controller. It relies on the
[NFS persistent volume](nfs-pv.yaml) and
[NFS persistent volume claim](nfs-pvc.yaml) in this example as well.
## Complete setup
The example below shows how to export a NFS share from a single pod replication
controller and import it into two replication controllers.
### NFS server part
Define [NFS server controller](nfs-server-rc.yaml) and
[NFS service](nfs-server-service.yaml):
```console
$ kubectl create -f examples/nfs/nfs-server-rc.yaml
$ kubectl create -f examples/nfs/nfs-server-service.yaml
```
The server exports `/mnt/data` directory as `/` (fsid=0). The
directory contains dummy `index.html`. Wait until the pod is running
by checking `kubectl get pods -lrole=nfs-server`.
### Create the NFS claim
The [NFS busybox controller](nfs-busybox-rc.yaml) uses a simple script to
generate data written to the NFS server we just started. First, you'll need to
find the cluster IP of the server:
```console
$ kubectl describe services nfs-server
```
Replace the invalid IP in the [nfs PV](nfs-pv.yaml). (In the future,
we'll be able to tie these together using the service names, but for
now, you have to hardcode the IP.)
Create the the [persistent volume](../../docs/user-guide/persistent-volumes.md)
and the persistent volume claim for your NFS server. The persistent volume and
claim gives us an indirection that allow multiple pods to refer to the NFS
server using a symbolic name rather than the hardcoded server address.
```console
$ kubectl create -f examples/nfs/nfs-pv.yaml
$ kubectl create -f examples/nfs/nfs-pvc.yaml
```
## Setup the fake backend
The [NFS busybox controller](nfs-busybox-rc.yaml) updates `index.html` on the
NFS server every 10 seconds. Let's start that now:
```console
$ kubectl create -f examples/nfs/nfs-busybox-rc.yaml
```
Conveniently, it's also a `busybox` pod, so we can get an early check
that our mounts are working now. Find a busybox pod and exec:
```console
$ kubectl get pod -lname=nfs-busybox
NAME READY STATUS RESTARTS AGE
nfs-busybox-jdhf3 1/1 Running 0 25m
nfs-busybox-w3s4t 1/1 Running 0 25m
$ kubectl exec nfs-busybox-jdhf3 -- cat /mnt/index.html
Thu Oct 22 19:20:18 UTC 2015
nfs-busybox-w3s4t
```
You should see output similar to the above if everything is working well. If
it's not, make sure you changed the invalid IP in the [NFS PV](nfs-pv.yaml) file
and make sure the `describe services` command above had endpoints listed
(indicating the service was associated with a running pod).
### Setup the web server
The [web server controller](nfs-web-rc.yaml) is an another simple replication
controller demonstrates reading from the NFS share exported above as a NFS
volume and runs a simple web server on it.
Define the pod:
```console
$ kubectl create -f examples/nfs/nfs-web-rc.yaml
```
This creates two pods, each of which serve the `index.html` from above. We can
then use a simple service to front it:
```console
kubectl create -f examples/nfs/nfs-web-service.yaml
```
We can then use the busybox container we launched before to check that `nginx`
is serving the data appropriately:
```console
$ kubectl get pod -lname=nfs-busybox
NAME READY STATUS RESTARTS AGE
nfs-busybox-jdhf3 1/1 Running 0 1h
nfs-busybox-w3s4t 1/1 Running 0 1h
$ kubectl get services nfs-web
NAME LABELS SELECTOR IP(S) PORT(S)
nfs-web role=web-frontend 10.0.68.37 80/TCP
$ kubectl exec nfs-busybox-jdhf3 -- wget -qO- http://10.0.68.37
Thu Oct 22 19:28:55 UTC 2015
nfs-busybox-w3s4t
```
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