This topic describes how to use an existing Server Load Balancer (SLB) instance with an Ingress to set up forwarding. You can use an annotation to specify an SLB instance by ID when you create an Ingress.

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.
  • A guaranteed-performance SLB instance is created in the virtual private cloud (VPC) where the ASK cluster is deployed. Guaranteed-performance SLB instances support elastic network interfaces (ENIs).
    • If you have an SLB instance in the VPC where the ASK cluster is deployed, you can log on to the SLB console and obtain the ID of the SLB instance on the Instances page.
    • If you have no SLB instance, you must create a guaranteed-performance SLB instance in the VPC where the ASK cluster is deployed. For example, you can select the slb.s2.small instance type. The SLB instance can be internal-facing or Internet-facing. For more information, see Create a CLB instance.
    • In this example, an Internet-facing SLB instance is used.

Procedure

Note The Ingress controller automatically opens port 80 and 443 on the SLB instance. Make sure that port 80 and 443 are not used by other services.

Step 1: Deploy an application

  1. Create the tomcat-service.yml file, copy the following code to the file, and run the kubectl apply -f tomcat-service.yml command to deploy a tomcat application for testing: 
    apiVersion: apps/v1 
kind: Deployment
metadata:
  name: tomcat
spec:
  replicas: 1
  selector:
    matchLabels:
      run: tomcat
  template:
    metadata:
      labels:
        run: tomcat
    spec:
      containers:
      - image: tomcat:7.0
        imagePullPolicy: Always
        name: tomcat
        ports:
        - containerPort: 8080
          protocol: TCP
      restartPolicy: Always
---
apiVersion: v1
kind: Service
metadata:
  name: tomcat
spec:
  ports:
  - port: 8080
    protocol: TCP
    targetPort: 8080
  selector:
    run: tomcat
  clusterIP: None

    The following output is returned:

    deployment "tomcat" created
service "tomcat" created
  2. Run the following command to view the application status: 
    kubectl get svc,deploy tomcat

    The following output is returned:

    NAME         TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)    AGE
svc/tomcat   ClusterIP   <none>       <none>        8080/TCP   1m

NAME            DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
deploy/tomcat   1         1         1            1           1m

Step 2: Configure an Ingress

  1. Create the tomcat-ingress.yml file, copy the following code to the file, and run the kubectl apply -f tomcat-ingress.yml command to configure an Ingress: 
    apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: tomcat-ingress
  annotations:
    # Specify the ID of the existing SLB instance.
    service.beta.kubernetes.io/alicloud-loadbalancer-id: lb-xxxxxxxxxx            ##Replace lb-xxxxxxxxxx with the ID of your SLB instance.
    service.beta.kubernetes.io/alicloud-loadbalancer-force-override-listeners: "true"
spec:
  ingressClassName: slb
  rules:
  # Configure a Layer 7 domain name.
  - host: bar.foo.com
    http:
      paths:
      # Configure a context path.
      - path: /
        backend:
          service: 
            name: tomcat
            port:
              number: 8080
        pathType: ImplementationSpecific

    The following output is returned:

    ingress "tomcat-ingress" created
  2. Run the following command to obtain the IP address of the SLB instance: 
    kubectl get ing tomcat-ingress

    The following output is returned:

    NAME             HOSTS         ADDRESS        PORTS     AGE
tomcat-ingress   bar.foo.com   47.168.XX.XX   80, 443   1m

Step 3: Access the application

Note You must resolve the domain name to the IP address of the SLB instance.
In this example, the following DNS rule is created for the domain name to enable access to the test application. 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. 
47.168.XX.XX    bar.foo.com
  • Access the tomcat application by using a browser. S10
  • Access the tomcat application by using the command line tool. 
    curl -k -H "Host: bar.foo.com" https://47.168.XX.XX