Configuring Application Traffic Mirroring for an Nginx Ingress

Preparations

• Two CCE standard clusters, cluster 1 and cluster 2, are available. For details, see Buying a CCE Standard/Turbo Cluster.
• The NGINX Ingress Controller add-on has been installed in both clusters.
• kubectl has been installed and configured to access the two clusters. For details, see .

Step 1: Creating a Workload and Exposing Services Through an Ingress

1. Deploy an application in cluster 1 and test the connection.
   Copy the following data and save it into the nginx-deploy.yaml file:

   apiVersion: apps/v1
   kind: Deployment
   metadata:
     labels:
       version: v1
     name: nginx
     namespace: default
   spec:
     selector:
       matchLabels:
         app: nginx
         version: v1
     template:
       metadata:
         labels:
           app: nginx
           version: v1
       spec:
         containers:
           - name: container-1
             image: nginx:latest
             imagePullPolicy: IfNotPresent
         terminationGracePeriodSeconds: 30
         dnsPolicy: ClusterFirst
     replicas: 1
   ---
   apiVersion: v1
   kind: Service
   metadata:
     name: nginx
     labels:
       app: nginx
     namespace: default
   spec:
     selector:
       app: nginx
     externalTrafficPolicy: Cluster
     ports:
       - name: cce-service-0
         targetPort: 80
         port: 80
         protocol: TCP
     type: NodePort
   ---
   apiVersion: networking.k8s.io/v1
   kind: Ingress
   metadata:
     name: nginx
     namespace: default
   spec:
     rules:
       - host: example.com
         http:
           paths:
             - path: /
               backend:
                 service:
                   name: nginx
                   port:
                     number: 80
               property:
                 ingress.beta.kubernetes.io/url-match-mode: STARTS_WITH
               pathType: ImplementationSpecific
     ingressClassName: nginx

2. Run the following command to create a workload for cluster 1:

   kubectl apply -f nginx-deploy.yaml

3. Repeat the preceding command to create the same workload in cluster 2.

Step 2: Configuring Traffic Replication

• As the destination of traffic, cluster 2 does not require any modifications. You only need to configure cluster 1.
• After the access traffic of the application in cluster 1 is replicated to the application in cluster 2, the client only receives the request response from cluster 1, while discarding the response from cluster 2.

Configure traffic mirroring for cluster 1. For more details, see Nginx Ingress Mirror.

kubectl patch ingress nginx --type merge --patch '"metadata": {"annotations": {"nginx.ingress.kubernetes.io/mirror-target": "http://<cluster_2_ingress_ip_address>:80/", "nginx.ingress.kubernetes.io/mirror-host": "example.com"}}'

In the preceding configuration, <cluster_2_ingress_ip_address> is the public IP address of the ingress load balancer in cluster 2.

Verification

Run the following command to access the application domain name example.com of cluster 1:

curl http://<cluster_1_ingress_ip_address>:80/ -H "Host: example.com"

Check nginx-ingress controller logs in cluster 1.

kubectl logs -f <cceaddon-nginx-ingress-controller_pod_name> -n kube-system

In the preceding command, <cceaddon-nginx-ingress-controller_pod_name> is the pod name of nginx-ingress controller.

According to the logs, whenever the domain name for the ingress in cluster 1 is requested, the request is duplicated and sent to the corresponding service in cluster 2.