volume-types.md

Volume Types

EmptyDir and HostPath

The following YAML file, for Pod ExampleA creates a Pod with two containers, one called alphacont, the other called betacont both with access to a shared volume called sharevol:

{% tabs %} {% tab title="EmptyDir" %}

 containers:
 - name: alphacont
   image: busybox
   volumeMounts:
   - mountPath: /alphadir
     name: sharevol
 - name: betacont
   image: busybox
   volumeMounts:
   - mountPath: /betadir
     name: sharevol
 volumes:
 - name: sharevol
   emptyDir: {} 

{% endtab %}

{% tab title="Hostpath" %}

 containers:
 - name: alphacont
   image: busybox
   volumeMounts:
   - mountPath: /alphadir
     name: sharevol
 - name: betacont
   image: busybox
   volumeMounts:
   - mountPath: /betadir
     name: sharevol
 volumes:
 - name: sharevol
   hostPath:
     path: /vol/dir

{% endtab %} {% endtabs %}

Run the file and check if it's mounted or not

$ kubectl exec -ti exampleA -c betacont -- touch /betadir/foobar
$ kubectl exec -ti exampleA -c alphacont -- ls -l /alphadir

You could use emptyDir or hostPath easily, since those types do not require any additional setup, and will work in your Kubernetes cluster.

Note that one container wrote, and the other container had immediate access to the data. There is nothing to keep the containers from overwriting the other’s data. Locking or versioning considerations must be part of the application to avoid corruption.