Storage Classes

In this lesson, we’ll explore how StorageClasses enable dynamic volume provisioning in Kubernetes. If you’re familiar with static provisioning—where you manually create cloud disks and bind them via PersistentVolumes (PVs) and PersistentVolumeClaims (PVCs)—you’ll see how StorageClasses automate this workflow.

Static Provisioning Recap
Dynamic Provisioning with StorageClass
StorageClass Definition
Using a Dynamic PVC and Pod
Comparing Provisioning Methods
Customizing StorageClass Parameters
Defining Service Tiers
Links and References

Static Provisioning Recap

With static provisioning, you manually create the underlying cloud disk before you define a PV:

gcloud beta compute disks create \
  --size=1GB \
  --region=us-east1 \
  pd-disk

Then you define:

# pv-definition.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv-vol1
spec:
  capacity:
    storage: 500Mi
  accessModes:
    - ReadWriteOnce
  gcePersistentDisk:
    pdName: pd-disk
    fsType: ext4

# pvc-definition.yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: myclaim
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 500Mi

# pod-definition.yaml
apiVersion: v1
kind: Pod
metadata:
  name: random-number-generator
spec:
  containers:
    - name: alpine
      image: alpine
      command: ["/bin/sh", "-c"]
      args:
        - shuf -i 0-100 -n 1 >> /opt/number.out
      volumeMounts:
        - name: data-volume
          mountPath: /opt
  volumes:
    - name: data-volume
      persistentVolumeClaim:
        claimName: myclaim

Static provisioning works, but each new disk requires manual cloud CLI steps. Maintenance and scaling can become cumbersome.

Dynamic Provisioning with StorageClass

With a StorageClass, Kubernetes can automatically create and bind a PV when you apply a PVC. This dynamic provisioning eliminates manual disk creation.

StorageClass Definition

Define a StorageClass that uses the GCE PD provisioner:

# sc-definition.yaml
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: google-storage
provisioner: kubernetes.io/gce-pd

Using a Dynamic PVC and Pod

Create a PVC that references your StorageClass:

# pvc-dynamic.yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: myclaim
spec:
  storageClassName: google-storage
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 500Mi

Deploy a Pod that mounts the PVC:

# pod-dynamic.yaml
apiVersion: v1
kind: Pod
metadata:
  name: random-number-generator
spec:
  containers:
    - name: alpine
      image: alpine
      command: ["/bin/sh", "-c"]
      args:
        - shuf -i 0-100 -n 1 >> /opt/output.txt
      volumeMounts:
        - name: data-volume
          mountPath: /opt
  volumes:
    - name: data-volume
      persistentVolumeClaim:
        claimName: myclaim

Kubernetes will then:

Provision a new GCE PD of the requested size.
Create a corresponding PV.
Bind your PVC to that PV.
Attach the volume to your Pod.

Comparing Provisioning Methods

Feature	Static Provisioning	Dynamic Provisioning (StorageClass)
Disk Creation	Manual via cloud CLI	Automated by Kubernetes
PV Definition	Pre-created `PersistentVolume`	Generated automatically
PVC Binding	Manual or automatic if labels match	Automatic
Scalability	Limited (manual work for each disk)	High (one PVC, one step)
Flexibility	Low	High (parameters, tiers, provisioners)

Customizing StorageClass Parameters

Most provisioners let you fine-tune disks. For GCE PD, you can specify:

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: google-storage
provisioner: kubernetes.io/gce-pd
parameters:
  type: pd-standard        # pd-standard or pd-ssd
  replication-type: none   # none or regional-pd

Be cautious with regional-pd: it offers high availability at higher cost. Always choose based on your SLA requirements.

Defining Service Tiers

You can create multiple StorageClasses to represent different performance tiers:

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: silver
provisioner: kubernetes.io/gce-pd
parameters:
  type: pd-standard
  replication-type: none
---
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: gold
provisioner: kubernetes.io/gce-pd
parameters:
  type: pd-ssd
  replication-type: none
---
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: platinum
provisioner: kubernetes.io/gce-pd
parameters:
  type: pd-ssd
  replication-type: regional-pd

Tier	Disk Type	Replication	Use Case
silver	pd-standard	none	Development, testing
gold	pd-ssd	none	Production, low-latency
platinum	pd-ssd	regional-pd	Mission-critical, high-availability

When you create a PVC, just set storageClassName to select your tier. Kubernetes handles provisioning and binding behind the scenes.

Links and References

Mastering StorageClasses empowers you to build scalable, self-service storage in your Kubernetes clusters—no more manual volume management!

Introduction

Docker Engine

Docker Image Management

Docker Engine - Security

Docker Engine - Networking

Docker Engine - Storage

Docker Compose

Docker Swarm

Kubernetes

Docker Engine Enterprise

Docker Trusted Registry

Disaster Recovery

Table of Contents

Static Provisioning Recap

Dynamic Provisioning with StorageClass

StorageClass Definition

Using a Dynamic PVC and Pod

Comparing Provisioning Methods

Customizing StorageClass Parameters

Defining Service Tiers

Links and References

Watch Video

​Table of Contents

​Static Provisioning Recap

​Dynamic Provisioning with StorageClass

​StorageClass Definition

​Using a Dynamic PVC and Pod

​Comparing Provisioning Methods

​Customizing StorageClass Parameters

​Defining Service Tiers

​Links and References

Watch Video

Table of Contents

Static Provisioning Recap

Dynamic Provisioning with StorageClass

StorageClass Definition

Using a Dynamic PVC and Pod

Comparing Provisioning Methods

Customizing StorageClass Parameters

Defining Service Tiers

Links and References