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StorageClasses

Our Managed Kubernetes clusters come with a couple of predefined storage classes. If there is no storage class that meets your needs, custom ones can be created. For more information take a look at the Cinder-CSI Driver documentation or feel free to contact our support team for assistance.

$ kubectl get sc
NAME                  PROVISIONER                RECLAIMPOLICY   VOLUMEBINDINGMODE      ALLOWVOLUMEEXPANSION
encrypted             cinder.csi.openstack.org   Delete          Immediate              true
encrypted-high-iops   cinder.csi.openstack.org   Delete          Immediate              true
high-iops             cinder.csi.openstack.org   Delete          Immediate              true
nws-storage           cinder.csi.openstack.org   Delete          Immediate              true
standard (default)    cinder.csi.openstack.org   Delete          Immediate              true

standard (Default)

---
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  annotations:
    storageclass.kubernetes.io/is-default-class: "true"
  name: standard
allowVolumeExpansion: true
parameters:
  csi.storage.k8s.io/fstype: ext4
provisioner: cinder.csi.openstack.org
reclaimPolicy: Delete
volumeBindingMode: Immediate

The StorageClass standard is the default class that is used when no StorageClass is specified.

It provisions an ext4 formatted Volume in OpenStack and deletes it if the referencing PersistentVolumeClaim (PVC) gets deleted. VolumeExpansion is also supported. It enables the user to update the size of a PVC and let Kubernetes handle the resize.

The IOPS limit is set to 1000 IOPS, but enables a boost of up to 2000 IOPS for 60s.

nws-storage

---
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: nws-storage
allowVolumeExpansion: true
parameters:
  csi.storage.k8s.io/fstype: xfs
provisioner: cinder.csi.openstack.org
reclaimPolicy: Delete
volumeBindingMode: Immediate

The nws-storage class is similar to standard, but uses xfs as it's filesystem.

This is useful for PersistentVolumeClaims with many small files, e.g. databases or logging systems, as xfs can scale inodes dynamically. This stands in contrast to ext4, which creates a fixed size of inodes at creation time.

high-iops

---
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: high-iops
parameters:
  csi.storage.k8s.io/fstype: ext4
  type: Ceph-High-IOPS
allowVolumeExpansion: true
provisioner: cinder.csi.openstack.org
reclaimPolicy: Delete
volumeBindingMode: Immediate

The high-iops StorageClass uses a different volume type in OpenStack called Ceph-High-IOPS, which allows the system up to 2000 IOPS for sustained loads and 4000 IOPS for bursts (60s).

encrypted(-high-iops)

---
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: encrypted
parameters:
  csi.storage.k8s.io/fstype: ext4
  type: Ceph-Encrypted(-High-IOPS)
allowVolumeExpansion: true
provisioner: cinder.csi.openstack.org
reclaimPolicy: Delete
volumeBindingMode: Immediate

The StorageClasses starting with encrypted use OpenStacks volume type that transparently enables encryption for the volume. The two classes differ in the same way standard and high-iops do.

Custom

You can of course also create your own StorageClass with any of the parameters and options available to the Cinder CSI Driver and Kubernetes.

For reference, the following custom StorageClass would use the Ceph-Encrypted Volume type with the XFS format while retaining the backing PersistentVolume after deleting the PersistentVolumeClaim:

$ kubectl apply -f - <<EOF
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: encrypted-xfs-retain
parameters:
  csi.storage.k8s.io/fstype: xfs
  type: Ceph-Encrypted
allowVolumeExpansion: true
provisioner: cinder.csi.openstack.org
reclaimPolicy: Retain
volumeBindingMode: Immediate
EOF

ReadWriteMany

Unfortunately, we currently don't provide Volumes with the RWX access type. This is on our roadmap, but we cannot commit to any timeframe at this point. For now, you will need to build your own solution, e.g. based on NFS or Rook Ceph. We would be happy to assist you with that.

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