When setting up a K8s environment the Storage Class by default is created with one main restriction and this is represented with the parameter allowVolumeExpansion: false
this will not allow you to expand your disk when these are filling up. It is recommended to create a new Storage Class with at least these next parameters:
reclaimPolicy: Retain
volumeBindingMode: WaitForFirstConsumer
allowVolumeExpansion: true
Here is an example working in a AWS environment:
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
name: io1
provisioner: kubernetes.io/aws-ebs
parameters:
type: io1
iopsPerGB: "50"
reclaimPolicy: Retain
volumeBindingMode: WaitForFirstConsumer
allowVolumeExpansion: true
and if you’re using GKE:
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
name: ssd
provisioner: kubernetes.io/gce-pd
parameters:
type: pd-ssd
reclaimPolicy: Retain
volumeBindingMode: WaitForFirstConsumer
allowVolumeExpansion: true
Check the Storage Class documentation for more details and other providers.
Do not forget using your custom Storage Class when you create a cluster, check the required parameters in Cluster Parameters
Important note: Make sure you include these parameters in order to avoid some of the next errors:
Autoscaler not working as expected:
cluster-autoscaler pod didn't trigger scale-up (it wouldn't fit if a new node is added)
Volumes not assigned:
N node(s) had no available volume zone
Losing data by accidentally removing a volume:
reclaimPolicy: Retain
will guarantee the volume is not delete when a claim no longer exist.