Kubrnetes: Example of StorageClass

Choose a storage class and set it as your default by setting the storageclass.kubernetes.io/is-default-class=true annotation.

$ kubectl patch storageclass CUSTOM_STORAGE_CLASS_NAME -p '{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"true"}}}'

$ kubectl annotate storageclass CUSTOM_STORAGE_CLASS_NAME storageclass.kubernetes.io/is-default-class=trueCode language: JavaScript (javascript)

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: CUSTOM_STORAGE_CLASS_NAME
provisioner: kubernetes.io/aws-ebs
reclaimPolicy: Retain
parameters:
  type: gp2
  zone: '*AWS_ZONE*'Code language: JavaScript (javascript)

kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: gp2
  annotations:
    storageclass.kubernetes.io/is-default-class: "true"
provisioner: kubernetes.io/aws-ebs
parameters:
  type: gp2
reclaimPolicy: Retain
mountOptions:
  - debug
allowedTopologies:
- matchLabelExpressions:
  - key: failure-domain.beta.kubernetes.io/zone
    values:
    - ap-southeast-1a
    - ap-southeast-1b
    - ap-southeast-1c

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: standard
provisioner: kubernetes.io/aws-ebs
parameters:
  type: gp2
reclaimPolicy: Retain
allowVolumeExpansion: true
mountOptions:
  - debug
volumeBindingMode: ImmediateCode language: JavaScript (javascript)

kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: gp2
  annotations:
    storageclass.kubernetes.io/is-default-class: "true"
provisioner: kubernetes.io/aws-ebs
parameters:
  type: gp2
  fsType: ext4 

Scheduling based on Node label selector

The ‘Allowed Topologies’ feature allows you select the Nodes where the application Pods may be scheduled based on Node labels.

The nodes which are preferred for scheduling may be labelled using a unique label and key. Multiple such labels and keys per label may be specified. All of the selection criteria is AND-ed.

The following is a sample StorageClass which allows scheduling on nodes with the labels kubernetes.io/hostname=worker-2, kubernetes.io/hostname=worker-3 and kubernetes.io/hostname=worker-5.

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: custom-hostpath
  annotations:
    openebs.io/cas-type: local
    cas.openebs.io/config: |
      - name: StorageType
        value: "hostpath"
      - name: BasePath
        value: "/var/openebs/local"
provisioner: openebs.io/local
volumeBindingMode: WaitForFirstConsumer
allowedTopologies:
- matchLabelExpressions:
  - key: kubernetes.io/hostname
    values:
    - worker-2
    - worker-3
    - worker-5Code language: JavaScript (javascript)

Rajesh Kumar

I’m Rajesh Kumar, a DevOps, SRE, DevSecOps, Cloud, and Platform Engineering expert passionate about sharing practical knowledge, real-world experiences, and industry best practices. I have worked at Cotocus and regularly write about technology, travel, investing, health, product reviews, and digital marketing through my various platforms.

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