Storage classes

The following article provides information on how version updates are handled for the STACKIT Kubernetes Engine (SKE) service.

Storage classes in STACKIT Kubernetes clusters

From the Kubernetes docs:

“A StorageClass provides a way for administrators to describe the “classes” of storage they offer. Different classes might map to quality-of-service levels, or to back up policies, or to arbitrary policies determined by the cluster administrators. Kubernetes itself is unopinionated about what classes represent. This concept is sometimes called “profiles” in other storage systems.”

SKE offers the following different storage classes based on the performance classes provided by the IaaS layer (see Basics Block Storage):

NAME PROVISIONER RECLAIMPOLICY VOLUMEBINDINGMODE ALLOWVOLUMEEXPANSION AGE
premium-perf0-stackit cinder.csi.openstack.org Delete Immediate true 33h
premium-perf1-stackit (default) cinder.csi.openstack.org Delete Immediate true 33h
premium-perf2-stackit cinder.csi.openstack.org Delete Immediate true 33h
premium-perf4-stackit cinder.csi.openstack.org Delete Immediate true 33h
premium-perf6-stackit cinder.csi.openstack.org Delete Immediate true 33h

A list of available storage classes in your Kubernetes cluster can be retrieved with the following command:

kubectl get storageclasses

Using storage classes for PVCs

To select a certain performance class for your Kubernetes persistent volumes be sure to set the storageClassName property to one of the available storage classes. In this example there one PVC is created with 20GB storage in the STACKIT Performance Class 4.

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: example
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 20Gi
  storageClassName: "premium-perf4-stackit"

If storageClassName is empty or absent than default StorageClass premium-perf1-stackit will be set.

Further information

For more information about persistent volumes and storageclasses you can find here: