Use the automatically created SLB instance - User Guide for Serverless Kubernetes Clusters| Alibaba Cloud Documentation Center

If you do not use an annotation to specify an existing Server Load Balancer (SLB) instance when you create an Ingress, the system automatically creates an Internet-facing SLB instance. This topic describes how to use the automatically created SLB instance with an Ingress to set up forwarding.

Prerequisites

A serverless Kubernetes (ASK) cluster is created. You must configure a network address translation (NAT) gateway for the virtual private cloud (VPC) where the cluster is created so that the cluster can download container images from the Internet. For more information, see Create an ASK cluster.
The kubectl client is connected to the ASK cluster. For more information, see Use kubectl to connect to an ASK cluster.

Procedure

Step 1: Deploy applications

Create the cafe-service.yaml file, copy the following code to the file, and run the kubectl apply -f cafe-service.yaml command to deploy a coffee application and a tea application:

apiVersion: apps/v1 
kind: Deployment
metadata:
  name: coffee
spec:
  replicas: 2
  selector:
    matchLabels:
      app: coffee
  template:
    metadata:
      labels:
        app: coffee
    spec:
      containers:
      - name: coffee
        image: registry.cn-hangzhou.aliyuncs.com/acs-sample/nginxdemos:latest
        ports:
        - containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
  name: coffee-svc
spec:
  ports:
  - port: 80
    targetPort: 80
    protocol: TCP
  selector:
    app: coffee
  clusterIP: None
---
apiVersion: apps/v1 
kind: Deployment
metadata:
  name: tea
spec:
  replicas: 1
  selector:
    matchLabels:
      app: tea 
  template:
    metadata:
      labels:
        app: tea 
    spec:
      containers:
      - name: tea 
        image: registry.cn-hangzhou.aliyuncs.com/acs-sample/nginxdemos:latest
        ports:
        - containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
  name: tea-svc
  labels:
spec:
  ports:
  - port: 80
    targetPort: 80
    protocol: TCP
  selector:
    app: tea
  clusterIP: None

The following output is returned:

deployment "coffee" created
service "coffee-svc" created
deployment "tea" created
service "tea-svc" created

Run the following command to view the application status:

kubectl get svc,deploy

The following output is returned:

NAME             TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
svc/coffee-svc   ClusterIP   <none>       <none>        80/TCP    1m
svc/tea-svc      ClusterIP   <none>       <none>        80/TCP    1m

NAME            DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
deploy/coffee   2         2         2            2           1m
deploy/tea      1         1         1            1           1m

Step 2: Configure an Ingress

Create the cafe-ingress.yaml file, copy the following code to the file, and run the kubectl apply -f cafe-ingress.yaml command to configure an Ingress. The Ingress specifies the domain name and path that are used to expose the coffee and tea applications to the Internet.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: cafe-ingress
spec:
  ingressClassName: slb
  rules:
  # Configure a Layer 7 domain name.
  - host: foo.bar.com
    http:
      paths:
      # Configure a context path.
      - path: /tea
        backend:
          service: 
            name: tea-svc
            port:
              number: 80
        pathType: ImplementationSpecific
      # Configure a context path.
      - path: /coffee
        backend:
          service: 
            name: coffee-svc
            port:
              number: 80
        pathType: ImplementationSpecific

The following output is returned:

ingress "cafe-ingress" created

Run the following command to obtain the IP address of the SLB instance:

kubectl get ing

The following output is returned:

NAME           HOSTS         ADDRESS          PORTS     AGE
cafe-ingress   foo.bar.com   139.168.XX.XX    80        1m

Step 3: Access the applications

Note You must resolve the domain name to the IP address of the SLB instance.

In this example, the following DNS rule is added for the domain name to enable access to the applications. We recommend that you apply for an Internet Content Provider (ICP) number for the domain name if the domain name is used in the production environment.

139.168.XX.XX    foo.bar.com

Access the coffee application.

Access the coffee application by using a browser.
Access the coffee application by using the command line tool.
```
curl -H "Host: foo.bar.com" http://139.168.XX.XX/coffee
```

Access the tea application.

Access the tea application by using a browser.
Access the tea application by using the command line tool.
```
curl -H "Host: foo.bar.com" http://139.168.XX.XX/tea
```