How to Create a Storage Class in Kubernetes¶

This guide explains how to create and use Storage Classes in Kubernetes for dynamic provisioning of persistent volumes.

Prerequisites¶

Running Kubernetes cluster
kubectl installed and configured
Storage provider/provisioner (cloud provider, local storage, etc.)

What is a Storage Class?¶

A StorageClass provides a way to describe the "classes" of storage offered by the cluster. Different classes might map to: - Quality-of-Service levels - Backup policies - Arbitrary policies determined by cluster administrators

Creating Storage Classes¶

Basic Storage Class¶

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: standard
provisioner: kubernetes.io/aws-ebs
parameters:
  type: gp2
reclaimPolicy: Delete
allowVolumeExpansion: true
volumeBindingMode: WaitForFirstConsumer

Storage Class with Different Providers¶

1. AWS EBS¶

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: fast
provisioner: kubernetes.io/aws-ebs
parameters:
  type: gp3
  iops: "3000"
  throughput: "125"

2. Azure Disk¶

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: managed-premium
provisioner: kubernetes.io/azure-disk
parameters:
  storageaccounttype: Premium_LRS
  kind: Managed

3. Google Cloud Persistent Disk¶

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: standard-gcp
provisioner: kubernetes.io/gce-pd
parameters:
  type: pd-standard
  replication-type: none

Using Storage Classes¶

1. Create PVC with Storage Class¶

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: fast-pvc
spec:
  accessModes:
    - ReadWriteOnce
  storageClassName: fast
  resources:
    requests:
      storage: 10Gi

2. Pod Using PVC with Storage Class¶

apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod
spec:
  containers:
  - name: nginx
    image: nginx
    volumeMounts:
    - name: data
      mountPath: /data
  volumes:
  - name: data
    persistentVolumeClaim:
      claimName: fast-pvc

Storage Class Parameters¶

Common Parameters¶

Volume Binding Mode

volumeBindingMode: WaitForFirstConsumer  # or Immediate

Reclaim Policy
```
reclaimPolicy: Delete  # or Retain
```
Allow Volume Expansion
```
allowVolumeExpansion: true
```

Production Examples¶

Multi-tier Storage Setup¶

---
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: fast-ssd
  labels:
    environment: production
annotations:
  storageclass.kubernetes.io/is-default-class: "false"
provisioner: kubernetes.io/aws-ebs
parameters:
  type: gp3
  iops: "16000"
  throughput: "1000"
  encrypted: "true"
reclaimPolicy: Retain
allowVolumeExpansion: true
volumeBindingMode: WaitForFirstConsumer
---
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: standard-hdd
  labels:
    environment: production
provisioner: kubernetes.io/aws-ebs
parameters:
  type: st1
  encrypted: "true"
reclaimPolicy: Delete
allowVolumeExpansion: true
volumeBindingMode: WaitForFirstConsumer

Application Using Multiple Storage Classes¶

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: postgres-ha
spec:
  serviceName: postgres
  replicas: 3
  selector:
    matchLabels:
      app: postgres
  template:
    metadata:
      labels:
        app: postgres
    spec:
      containers:
      - name: postgres
        image: postgres:13
        volumeMounts:
        - name: data
          mountPath: /var/lib/postgresql/data
        - name: backup
          mountPath: /backup
  volumeClaimTemplates:
  - metadata:
      name: data
    spec:
      accessModes: [ "ReadWriteOnce" ]
      storageClassName: fast-ssd
      resources:
        requests:
          storage: 100Gi
  - metadata:
      name: backup
    spec:
      accessModes: [ "ReadWriteOnce" ]
      storageClassName: standard-hdd
      resources:
        requests:
          storage: 500Gi

Best Practices¶

1. Storage Class Design¶

Create classes for different performance needs
Consider cost implications
Plan for scalability

2. Security¶

Enable encryption
Use appropriate access modes
Implement backup strategies

3. Performance¶

Match storage class to workload requirements
Monitor storage performance
Configure appropriate IOPS and throughput

Common Operations¶

Managing Storage Classes¶

# List storage classes
kubectl get storageclass

# Get storage class details
kubectl describe storageclass storage-class-name

# Set default storage class
kubectl patch storageclass storage-class-name -p '{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"true"}}}'

Volume Management¶

# List PVCs using storage class
kubectl get pvc --all-namespaces -o custom-columns=NAME:.metadata.name,STORAGECLASS:.spec.storageClassName

# Check PV provisioning status
kubectl get pv -o custom-columns=NAME:.metadata.name,STORAGECLASS:.spec.storageClassName,STATUS:.status.phase

Troubleshooting¶

Common Issues and Solutions¶

PVC Stuck in Pending

# Check PVC status
kubectl describe pvc pvc-name

# Verify storage class exists
kubectl get storageclass

Volume Provisioning Failed

# Check events
kubectl get events --field-selector involvedObject.name=pvc-name

# Check cloud provider quotas and limits

Performance Issues

# Monitor storage metrics
kubectl top pod pod-name

# Check storage class parameters
kubectl describe storageclass storage-class-name

Advanced Configurations¶

1. Custom Storage Provisioner¶

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: custom-storage
provisioner: custom.provisioner/nfs
parameters:
  server: nfs-server.default.svc.cluster.local
  path: /shares
  readOnly: "false"

2. Storage Class with Topology¶

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: topology-aware
provisioner: kubernetes.io/aws-ebs
parameters:
  type: gp3
allowedTopologies:
- matchLabelExpressions:
  - key: topology.kubernetes.io/zone
    values:
    - us-east-1a
    - us-east-1b

Next Steps¶

Implement automated storage management
Set up monitoring and alerts
Create backup and disaster recovery plans
Study advanced storage patterns
Explore CSI drivers