:Migrate Nginx Ingress to ASM gateway

Step 2: Create an ASM gateway

You need to create an ASM gateway using YAML. However, you can still use the ASM gateway to create a page for visual configuration. Click the preview button at the bottom of the page to directly obtain a basic YAML file. After obtaining the file, you need to edit the serviceAnnotations in the YAML and add the following service annotations to reuse the CLB instance of Nginx Ingress.

service.beta.kubernetes.io/alibaba-cloud-loadbalancer-id: ${CLB instance ID}

service.beta.kubernetes.io/alibaba-cloud-loadbalancer-force-override-listeners: "false"

service.beta.kubernetes.io/alibaba-cloud-loadbalancer-vgroup-port: If you have multiple port and vServer group combinations, separate them with commas (,). For example, "${YOUR_VGROUP_ID_1}:80, ${YOUR_VGROUP_ID_2}:443". Note that you need to provide the vServer group ID, not the previously named name such as shared-80.

service.beta.kubernetes.io/alibaba-cloud-loadbalancer-weight: "0"

Example of ServiceAnnotations:

 serviceAnnotations:
    service.beta.kubernetes.io/alibaba-cloud-loadbalancer-id: "lb-xxxxx"  // Replace lb-xxxxx with the ID of the CLB instance that you created in the CLB console.
    service.beta.kubernetes.io/alibaba-cloud-loadbalancer-force-override-listeners: 'false'  // This must be explicitly set to false because Istio gateway overrides listeners by default.
    service.beta.kubernetes.io/alibaba-cloud-loadbalancer-vgroup-port: "${YOUR_VGROUP_ID}:80"   // Replace ${YOUR_VGROUP_ID} with the virtual server.
    service.beta.kubernetes.io/alibaba-cloud-loadbalancer-weight: "0"   // Set the service traffic weight. Initially set to 0 so the ASM gateway does not receive traffic.

Step 3: Manually transform ingress to VS, DR, and other Istio configurations

Transform Ingress into the corresponding VirtualService configuration for Istio. You can refer to the following Ingress configuration.

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: helloworld
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /$2
spec:
  rules:
    - http:
        paths:
          - backend:
              serviceName: helloworld
              servicePort: 80
            path: /helloworld(/|$)(.*)
      host: example.com

Expected output:

apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
  name: example-vs
spec:
  gateways:
  - istio-system/ingressgateway  ## your gateway name
  hosts:
  - example.com
  http:
  - name: route-helloworld
    match:
    - uri:
        prefix: /helloworld/
    - uri:
        prefix: /helloworld
    rewrite:
      uri: /
    route:
    - destination:
        host: helloworld
        port:
          number: 80

VirtualService and DestinationRule can be placed in the same namespace, with the service Deployment. If they are not in the same namespace, the destination.host field needs to be filled in FQDN format.