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 clusters 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

Connect to Kubernetes clusters by using kubectl.

Create a YAML file named nginx.yaml and copy the following content to the file:

apiVersion: v1
kind: Service
metadata:
  name: nginx-service
spec:
  ports:
  - port: 80
    protocol: TCP
  selector:
    app: nginx
  type: LoadBalancer
---
apiVersion: apps/v1  #Specify the version based on the Kubernetes version that you use. 
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"

Note The relationships between Kubernetes versions and the apiVersion of Deployments:

Kubernetes versions earlier than 1.6: extensions/v1beta1.
Kubernetes 1.6 to 1.9: apps/v1beta1.
Kubernetes versions later than 1.9: apps/v1.

Run the following command to deploy an NGINX application in the ASK cluster:

kubectl apply -f nginx.yaml

Expected output:

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.
1. Run the following command to query the states of the pods that are provisioned for the application:
```
kubectl get pod
```
  Expected output:
```
nginx-deploy-55d8dcf755-bxk8n   1/1     Running   0          36s
nginx-deploy-55d8dcf755-rchhq   1/1     Running   0          36s
```
2. Run the following command to query the states of the created Services:
```
kubectl get svc
```
  Expected output:
```
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
```
3. Run the following command to use the IP address of the created SLB instance to access the NGINX application:
```
curl 47.57.**.**
```
  Expected output:
```
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
...
</html>
```

Scale out the created Deployment.

Run the following command to query the created Deployment:

kubectl get deploy

Expected output:

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

Run the following command to scale out the created Deployment:

kubectl scale deploy nginx-deploy --replicas=10

Expected output:

deployment.extensions/nginx-deploy scaled

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

kubectl get pod

Expected output:

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