Quickstart: Deploy an application using the Dapr cluster extension for Azure Kubernetes Service (AKS) or Arc-enabled Kubernetes

Artikel
08/01/2024

In this quickstart, you use the Dapr cluster extension in an AKS or Arc-enabled Kubernetes cluster. You deploy a hello world example, which consists of a Python application that generates messages and a node application that consumes and persists the messages.

Prerequisites

An Azure subscription. If you don't have an Azure subscription, you can create a free account.
Azure CLI or Azure PowerShell installed.
An AKS or Arc-enabled Kubernetes cluster with the Dapr cluster extension enabled.

Clone the repository

Clone the Dapr quickstarts repository using the git clone command.
```
git clone https://github.com/dapr/quickstarts.git
```
Change to the hello-kubernetes directory using cd.
```
cd quickstarts/tutorials/hello-kubernetes/
```

Create and configure a state store

Dapr can use many different state stores, such as Redis, Azure Cosmos DB, DynamoDB, and Cassandra, to persist and retrieve state. For this example, we use Redis.

Create a Redis store

Open the Azure portal to start the Azure Cache for Redis creation flow.
Fill out the necessary information.
Select Create to start the Redis instance deployment.
Take note of the hostname of your Redis instance, which you can retrieve from the Overview section in Azure. The hostname might be similar to the following example: xxxxxx.redis.cache.windows.net:6380.
Under Settings, navigate to Access keys to get your access keys.
Create a Kubernetes secret to store your Redis password using the kubectl create secret generic redis command.
```
kubectl create secret generic redis --from-literal=redis-password=<your-redis-password>
```

Configure the Dapr components

Once your store is created, you need to add the keys to the redis.yaml file in the deploy directory of the Hello World repository. You can learn more here.

Replace the redisHost value with your own Redis master address.
Replace the redisPassword with your own Secret.

Add the following two lines below redisPassword to enable connection over TLS

- name: redisPassword
    secretKeyRef:
      name: redis
      key: redis-password
- name: enableTLS
  value: true

Apply the configuration

Apply the redis.yaml file using the kubectl apply command.
```
kubectl apply -f ./deploy/redis.yaml
```
Verify your state store was successfully configured using the kubectl get components.redis command.
```
kubectl get components.redis -o yaml
```
You should see output similar to the following example output:
```
component.dapr.io/statestore created
```

Deploy the Node.js app with the Dapr sidecar

Apply the Node.js app deployment to your cluster using the kubectl apply command.
```
kubectl apply -f ./deploy/node.yaml
```
Note

Kubernetes deployments are asynchronous, which means you need to wait for the deployment to complete before moving on to the next steps. You can do so with the following command:
```
kubectl rollout status deploy/nodeapp
```
This deploys the Node.js app to Kubernetes. The Dapr control plane automatically injects the Dapr sidecar to the Pod. If you take a look at the node.yaml file, you see how Dapr is enabled for that deployment:
- dapr.io/enabled: true: tells the Dapr control plane to inject a sidecar to this deployment.
- dapr.io/app-id: nodeapp: assigns a unique ID or name to the Dapr application, so it can be sent messages to and communicated with by other Dapr apps.
Access your service using the kubectl get svc command.
```
kubectl get svc nodeapp
```
Make note of the EXTERNAL-IP in the output.

Verify the service

Call the service using curl with your EXTERNAL-IP.
```
curl $EXTERNAL_IP/ports
```
You should see output similar to the following example output:
```
{"DAPR_HTTP_PORT":"3500","DAPR_GRPC_PORT":"50001"}
```

Submit an order to the application using curl.

curl --request POST --data "@sample.json" --header Content-Type:application/json $EXTERNAL_IP/neworder

Confirm the order has persisted by requesting it using curl.
```
curl $EXTERNAL_IP/order
```
You should see output similar to the following example output:
```
{ "orderId": "42" }
```

Deploy the Python app with the Dapr sidecar

Navigate to the Python app directory in the hello-kubernetes quickstart and open app.py.

This example is a basic Python app that posts JSON messages to localhost:3500, which is the default listening port for Dapr. You can invoke the Node.js application's neworder endpoint by posting to v1.0/invoke/nodeapp/method/neworder. The message contains some data with an orderId that increments once per second:
```
n = 0
while True:
    n += 1
    message = {"data": {"orderId": n}}

    try:
        response = requests.post(dapr_url, json=message)
    except Exception as e:
        print(e)

    time.sleep(1)
```
Deploy the Python app to your Kubernetes cluster using the kubectl apply command.
```
kubectl apply -f ./deploy/python.yaml
```
Note

As with the previous command, you need to wait for the deployment to complete before moving on to the next steps. You can do so with the following command:
```
kubectl rollout status deploy/pythonapp
```

Observe messages and confirm persistence

Now that both the Node.js and Python applications are deployed, you watch messages come through.

Get the logs of the Node.js app using the kubectl logs command.

kubectl logs --selector=app=node -c node --tail=-1

If the deployments were successful, you should see logs like the following example logs:

Got a new order! Order ID: 1
Successfully persisted state
Got a new order! Order ID: 2
Successfully persisted state
Got a new order! Order ID: 3
Successfully persisted state

Call the Node.js app's order endpoint to get the latest order using curl.
```
curl $EXTERNAL_IP/order
{"orderID":"42"}
```
You should see the latest JSON in the response.

Remove the resource group, cluster, namespace, and all related resources using the az group delete command.
```
az group delete --name MyResourceGroup
```

Next steps

Learn how to create the Dapr extension

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