If you have a Kubernetes cluster running for couple of years, you would probably have legacy StorageClass defined which does not contain allowVolumeExpansion: true bit set. If this bit is not set on your storageClass, then you cannot expand your PVCs which are using this storageClass.
But, if you try to edit storage class to add this attribute to the specs, kubernetes does not allow you to do so saying that this field is immutable and cannot be changed after definition.
So now, how do we expand these PVCs which are created using legacy storage class without allowVolumeExpansion bit set?
It turns out – its quite easy. You can delete your old storage class without affecting your PVCs. And recreate it again, with same name, but this time with allowVolumeExpansion: true in the sepcs.
Now the old PVCs which were creating using the said StorageClass can now be expanded, automatically!!
That’s it for today!