NFS Persistent Volume Claim remains pending indefinitely - kubernetes

Question

I get the following error when creating a PVC and I have no idea what it means.
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal ExternalExpanding 1m (x3 over 5m) volume_expand Ignoring the PVC: didn't find a plugin capable of expanding the volume; waiting for an external
controller to process this PVC.
My PV for it is there and seems to be fine.
Here is the spec for my PV and PVC.
apiVersion: v1
kind: PersistentVolume
metadata:
creationTimestamp: null
finalizers:
- kubernetes.io/pv-protection
labels:
app: projects-service
app-guid: design-center-projects-service
asset: service
chart: design-center-projects-service
class: projects-service-nfs
company: mulesoft
component: projects
component-asset: projects-service
heritage: Tiller
product: design-center
product-component: design-center-projects
release: design-center-projects-service
name: projects-service-nfs
selfLink: /api/v1/persistentvolumes/projects-service-nfs
spec:
accessModes:
- ReadWriteOnce
capacity:
storage: 30Gi
claimRef:
apiVersion: v1
kind: PersistentVolumeClaim
name: projects-service-nfs-block
namespace: design-center
resourceVersion: "7932052"
uid: d114dd38-f411-11e8-b7b1-1230f683f84a
mountOptions:
- nfsvers=3
- hard
- sync
nfs:
path: /
server: 1.1.1.1
persistentVolumeReclaimPolicy: Retain
volumeMode: Block
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
creationTimestamp: null
finalizers:
- kubernetes.io/pvc-protection
labels:
app: projects-service
app-guid: design-center-projects-service
asset: service
chart: design-center-projects-service
company: mulesoft
component: projects
component-asset: projects-service
example: test
heritage: Tiller
product: design-center
product-component: design-center-projects
release: design-center-projects-service
name: projects-service-nfs-block
selfLink: /api/v1/namespaces/design-center/persistentvolumeclaims/projects-service-nfs-block
spec:
accessModes:
- ReadWriteOnce
dataSource: null
resources:
requests:
storage: 20Gi
selector:
matchLabels:
class: projects-service-nfs
storageClassName: ""
volumeMode: Block
volumeName: projects-service-nfs
Version:
$ kubectl version
Client Version: version.Info{Major:"1", Minor:"11", GitVersion:"v1.11.2", GitCommit:"bb9ffb1654d4a729bb4cec18ff088eacc153c239", GitTreeState:"clean", BuildDate:"2018-08-08T16:31:10Z", GoVersion:"go1.10.3", Compiler:"gc", Platform:"darwin/amd64"}
Server Version: version.Info{Major:"1", Minor:"12", GitVersion:"v1.12.1", GitCommit:"4ed3216f3ec431b140b1d899130a69fc671678f4", GitTreeState:"clean", BuildDate:"2018-10-05T16:36:14Z", GoVersion:"go1.10.4", Compiler:"gc", Platform:"linux/amd64"}

Answer 1

Looks like at some point you updated/expanded the PVC? which is calling:
func (expc *expandController) pvcUpdate(oldObj, newObj interface{})
...
The in the function it's trying to find a plugin for expansion and it can't find it with this:
volumePlugin, err := expc.volumePluginMgr.FindExpandablePluginBySpec(volumeSpec)
if err != nil || volumePlugin == nil {
err = fmt.Errorf("didn't find a plugin capable of expanding the volume; " +
"waiting for an external controller to process this PVC")
...
return
}
If you see this document it shows that the following volume types support PVC expansion with in-tree plugins: AWS-EBS, GCE-PD, Azure Disk, Azure File, Glusterfs, Cinder, Portworx, and Ceph RBD. So NFS is not one of them and that's why you are seeing the event. Looks like it could be supported in the future or also it could be supported with a custom plugin.
If you haven't updated the PVC I would recommend using the same capacity for the PV and PVC as described here