Deploy NGINX applications in ASK clusters - User Guide for Serverless Kubernetes Clusters| Alibaba Cloud Documentation Center

You do not need to create or manage nodes in serverless Kubernetes (ASK) clusters. This frees you from maintaining cloud resources for your applications and allows you to focus on your business development instead of managing the underlying infrastructure. This topic describes how to deploy web applications in ASK clusters.

Prerequisites

Create an ASK cluster

Background information

ASK cluster support standard Kubernetes semantics and API operations. You can create cluster resources with a few clicks, such as Deployments, StatefulSets, Jobs, Services, Ingresses, and custom resources. You can also use Helm to deploy a variety of Kubernetes-native applications in ASK clusters.

Procedure

Use kubectl to connect to an ACK cluster.

Create a file named nginx.yaml and copy the following content into the file.

apiVersion: v1
kind: Service
metadata:
  name: nginx-service
spec:
  ports:
  - port: 80
    protocol: TCP
  selector:
    app: nginx
  type: LoadBalancer
---
apiVersion: apps/v1beta2
kind: Deployment
metadata:
  name: nginx-deploy
  labels:
    app: nginx
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image:  nginx:alpine
        ports:
        - containerPort: 80
        resources:
          requests:
            cpu: "2"
            memory: "4Gi"

Deploy the nginx.yaml file.

kubectl apply -f nginx.yaml

service/nginx-service created
deployment.apps/nginx-deploy created

Check the states of the deployed pods and Services. You can use the IP address of the created Server Load Balancer (SLB) instance to access the NGINX application.

Run the following command to query the states of the NGINX pods:

kubectl get pod

nginx-deploy-55d8dcf755-bxk8n   1/1     Running   0          36s
nginx-deploy-55d8dcf755-rchhq   1/1     Running   0          36s

Run the following command to query the state of the created Service:

kubectl get svc

NAME            TYPE           CLUSTER-IP     EXTERNAL-IP   PORT(S)        AGE
kubernetes      ClusterIP      172. **. *.*     <none>        443/TCP        10d
nginx-service   LoadBalancer   172.19. *. ***   47.57. **. **   80:32278/TCP   39s

Run the following command to use the IP address of the created SLB instance to access the NGINX application:
```
curl 47.57. **. **
```
```
<! DOCTYPE html>
<html>
<head>
<title>Welcome to nginx! </title>
...
</html>
```

Scale out the NGINX Deployment.

Run the following command to query the NGINX Deployment:

kubectl get deploy

NAME           READY   UP-TO-DATE   AVAILABLE   AGE
nginx-deploy   2/2     2            2           9m32s

Run the following command to scale out the NGINX Deployment:

kubectl scale deploy nginx-deploy --replicas=10

deployment.extensions/nginx-deploy scaled

Run the following command to query the NGINX pods after the NGINX application is scaled out:

kubectl get pod

NAME                            READY   STATUS    RESTARTS   AGE
nginx-deploy-55d8dcf755-8jlz2   1/1     Running   0          39s
nginx-deploy-55d8dcf755-9jbzk   1/1     Running   0          39s
nginx-deploy-55d8dcf755-bqhcz   1/1     Running   0          38s
nginx-deploy-55d8dcf755-bxk8n   1/1     Running   0          10m
nginx-deploy-55d8dcf755-cn6x9   1/1     Running   0          38s
nginx-deploy-55d8dcf755-jsqjn   1/1     Running   0          38s
nginx-deploy-55d8dcf755-lhp8l   1/1     Running   0          38s
nginx-deploy-55d8dcf755-r2clb   1/1     Running   0          38s
nginx-deploy-55d8dcf755-rchhq   1/1     Running   0          10m
nginx-deploy-55d8dcf755-xspnt   1/1     Running   0          38s

You can use Horizontal Pod Autoscaler (HPA) to automatically scale out the NGINX Deployment when the CPU usage exceeds the scale-out threshold. After HPA is enabled, more pod replicas are added for the NGINX Deployment when the CPU usage exceeds the scale-out threshold.
1. Run the following command to scale in the number of pod replicas to one for the NGINX Deployment:
```
kubectl scale deploy nginx-deploy --replicas=1
```
```
deployment.extensions/nginx-deploy scaled
```
2. Run the following command to query the state of the NGINX pod:
```
kubectl get pod
```
```
NAME                            READY   STATUS    RESTARTS   AGE
nginx-deploy-55d8dcf755-rchhq   1/1     Running   0          16m
```
3. Run the following command to configure the scaling settings of HPA:
```
kubectl autoscale deployment nginx-deploy --cpu-percent=50 --min=1 --max=10
```
```
horizontalpodautoscaler.autoscaling/nginx-deploy autoscaled
```
4. Run the following command to query the state of HPA:
```
kubectl get hpa
```
```
NAME           REFERENCE                 TARGETS   MINPODS   MAXPODS   REPLICAS   AGE
nginx-deploy   Deployment/nginx-deploy   0%/30%    1         10        1          35s
```