Deploying Stateful Applications with Azure Disk and Azure Files - Tutorial

Prerequisites

Before you begin, ensure you have the following prerequisites:

• An Azure subscription
• An AKS cluster deployed

Step 1: Create Azure Disk or Azure Files

To deploy a stateful application in AKS, you need to create Azure Disk or Azure Files as persistent storage. Follow these steps:

1. Create an Azure Disk by running the following Azure CLI command:

2. Create an Azure Files share by running the following Azure CLI command:

Step 2: Define Persistent Volume and Persistent Volume Claim

Next, you need to define Persistent Volume (PV) and Persistent Volume Claim (PVC) to associate the created storage with your stateful application. Follow these steps:

1. Create a PV manifest file specifying the storage details:

apiVersion: v1
kind: PersistentVolume
metadata:
  name: my-pv
spec:
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteOnce
  azureDisk:
    diskName: 
    diskURI: 
    fsType: 

2. Create a PVC manifest file specifying the desired storage capacity and access mode:

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

Step 3: Deploy Stateful Application with PVC

Finally, you can deploy your stateful application using the defined PVC. Follow these steps:

1. Create an application deployment manifest file specifying the PVC:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app
spec:
  replicas: 1
  selector:
    matchLabels:
      app: my-app
  template:
    metadata:
      labels:
        app: my-app
    spec:
      containers:
        - name: my-container
          image: my-image
          volumeMounts:
            - name: data
              mountPath: /data
      volumes:
        - name: data
          persistentVolumeClaim:
            claimName: my-pvc

2. Create the application deployment using the manifest file:

Common Mistakes to Avoid

• Using the incorrect disk or share name when creating the PV or PVC.
• Not specifying the correct access mode for the PV and PVC.
• Forgetting to associate the PVC with the deployment manifest, resulting in the application not using the intended storage.

Frequently Asked Questions

1. Can I use Azure Files for data storage in a multi-node AKS cluster?

   Yes, Azure Files can be used as a shared storage solution in a multi-node AKS cluster, allowing multiple pods to access the same files simultaneously.

2. Can I use an existing Azure Disk or Azure Files for my stateful application?

   Yes, you can use existing Azure Disk or Azure Files by specifying their names and URIs in the PV manifest file.

3. Can I use different access modes for a PVC?

   Yes, depending on your application's requirements, you can use different access modes such as ReadWriteOnce, ReadOnlyMany, or ReadWriteMany for your PVC.

4. Can I resize an Azure Disk or Azure Files used by a PVC?

   Yes, you can resize an Azure Disk by running the following Azure CLI command:

   az disk update --resource-group --name --size-gb

   For Azure Files, you can change the quota limit by running the following Azure CLI command:

   az storage share update --name --account-name --quota

5. Can I use managed disks with AKS?

   Yes, AKS supports the use of managed disks, which provide scalable and durable storage for your stateful applications.

Summary

Deploying stateful applications in Azure Kubernetes Service (AKS) requires the use of persistent storage. By following the steps outlined in this tutorial, including creating Azure Disk or Azure Files, defining Persistent Volume and Persistent Volume Claim, and deploying your stateful application with the PVC, you can ensure that your application data is stored reliably and can be accessed across different pods and nodes. Avoid common mistakes such as using incorrect disk or share names or forgetting to associate the PVC with the deployment manifest. With Azure Disk and Azure Files, you can deploy and manage stateful applications effectively in AKS.