Alibaba Cloud Service Mesh (ASM) provides cross-region traffic distribution and failover capabilities for applications. The cross-region traffic distribution feature implements cross-region load balancing by routing traffic to multiple clusters based on their weights. The cross-region failover feature implements cross-region disaster recovery by transferring traffic from a faulty region to another region. This topic shows you how to use the cross-region failover and traffic distribution features to implement cross-region disaster recovery and load balancing. In the example of this topic, the Bookinfo application is used.

Plan a network

Before you use ASM, you must complete network configurations for ASM. This involves the CIDR blocks and names of vSwitches, virtual private clouds (VPCs), and clusters. In this example, a network is created based on the following plan:
Note For more information about how to plan for CIDR blocks of multiple clusters on the data plane, see Plan CIDR blocks for multiple clusters on the data plane.
  • Network plan for vSwitches and VPCs
    • vSwitches
      Notice To prevent route conflicts when you use Cloud Enterprise Network (CEN) to connect to a VPC, specify a unique CIDR block for each vSwitch.
      Category vSwitch VPC IPv4 CIDR block
      Cluster vpc-hangzhou-switch-1 vpc-hangzhou 20.0.0.0/16
      vpc-shanghai-switch-1 vpc-shanghai 21.0.0.0/16
      ASM instance vpc-hangzhou-switch-2 vpc-hangzhou2 192.168.0.0/24
    • VPCs
      Category VPC Region IPv4 CIDR block
      Cluster vpc-hangzhou cn-hangzhou 20.0.0.0/8
      vpc-shanghai cn-shanghai 21.0.0.0/8
      ASM instance vpc-hangzhou2 cn-hangzhou 192.168.0.0/16
  • Network plan for pods and services in clusters
    Cluster Region VPC Pod CIDR block Service CIDR block
    ack-hangzhou cn-hangzhou vpc-hangzhou 10.0.0.0/16 172.16.0.0/16
    ack-shanghai cn-shanghai vpc-shanghai 10.1.0.0/16 172.17.0.0/16

Step 1: Create clusters in different regions

  1. Create two vSwitches in the China (Hangzhou) and China (Shanghai) regions based on the preceding plan, and then create VPCs that are associated with the vSwitches. For more information, see Create a vSwitch and Create a VPC.
  2. Use the VPCs that you created and the preceding network plan to create clusters in the China (Hangzhou) and China (Shanghai) regions. For more information, see Create an ACK managed cluster.
  3. Create an ASM instance in the China (Hangzhou) region based on the preceding network plan. For more information, see Create an ASM instance.

Step 2: Use CEN to implement cross-region VPC communication

You can connect the VPCs among clusters and those between the clusters and the ASM instance by using CEN.

  1. Create a CEN instance.
    Note In this example, a CEN instance is created in the earlier version of the CEN console. You can click Previous Version in the upper-right corner of the CEN console to use the earlier version.
    1. Log on to the CEN console.
    2. On the Instances page, click Create CEN Instance.
    3. In the Create CEN Instance panel, set the parameters and click OK.
      Parameter Description
      Name The name of the CEN instance.

      The name must be 2 to 128 characters in length and can contain digits, underscores (_), and hyphens (-). The name must start with a letter.

      Description The description of the CEN instance.
      Network Type The type of the network instance that you want to attach to the CEN instance. In this example, VPC is used.
      Region The region in which the network instance that you want to attach resides. In this example, China (Hangzhou) is used.
      Networks The network instance that you want to attach. In this example, the VPC that you created in the China (Hangzhou) region is used.
  2. Attach network instances.
    1. Attach the VPC of the cluster that resides in the China (Shanghai) region.
      1. On the Instances page, find the CEN instance that you created and click its ID.
      2. Click the Networks tab, and then click Attach Network.
      3. In the Attach Network panel, set the parameters on the Your Account tab and click OK.
        Parameter Description
        Network Type The type of the network instance that you want to attach to the CEN instance. In this example, VPC is used.
        Region The region in which the network instance that you want to attach resides. In this example, China (Shanghai) is used.
        Networks The network instance that you want to attach. In this example, the VPC that you created in the China (Shanghai) region is used.
    2. Attach the VPC of the ASM instance that resides in the China (Hangzhou) region.
      1. Click the Networks tab, and then click Attach Network.
      2. In the Attach Network panel, set the parameters on the Your Account tab and click OK.
        Parameter Description
        Network Type The type of the network instance that you want to attach to the CEN instance. In this example, VPC is used.
        Region The region in which the network instance that you want to attach resides. In this example, China (Hangzhou) is used.
        Networks The network instance that you want to attach. In this example, the VPC that you created in the China (Hangzhou) region is used.
  3. Purchase a bandwidth plan. For more information, see Purchase a bandwidth plan.
  4. Set the cross-region connection bandwidth.
    1. On the Instances page, find the CEN instance that you created and click its ID.
    2. Click the Region Connections tab, and then click Set Region Connection.
    3. In the Set Region Connection panel, select the bandwidth plan that you purchased from the Bandwidth Plans drop-down list, set the Connected Regions parameter to China (Shanghai) and China (Hangzhou), and then click OK.
  5. Add security group rules.
    Add the pod CIDR block of the ack-shanghai cluster to the security group of the ack-hangzhou cluster and vice versa. This allows IP addresses from within the pod CIDR block of a cluster to access the other cluster.
    1. Log on to the ACK console.
    2. On the Clusters page, find the ack-shanghai cluster and click Details in the Actions column.
    3. On the Cluster Information page, click the Basic Information tab.
      View the pod CIDR block of the ack-shanghai cluster and go back to the Clusters page.
    4. On the Clusters page, find the ack-hangzhou cluster and click Details in the Actions column.
    5. On the Cluster Information page, click the Cluster Resources tab. Then, click the security group ID next to Security Group.
    6. On the Security Group Rules page, click Add Rule on the Inbound tab.
    7. Set the Protocol Type parameter to All and the Source parameter to the pod CIDR block of the ack-shanghai cluster. Then, click Save in the Actions column.
    8. Repeat the preceding substeps to view the pod CIDR block of the ack-hangzhou cluster and add the pod CIDR block to the security group of the ack-shanghai cluster.

Step 3: Publish the pod route information to CEN

  1. Log on to the ACK console.
  2. On the Clusters page, find the ack-hangzhou cluster and click Details in the Actions column.
  3. On the cluster details page, click the Cluster Resources tab and click the VPC ID next to VPC.
  4. On the Information tab, view the router ID in the vRouter Basic Information section.
  5. In the left-side navigation pane of the VPC console, click Route Tables.
  6. On the Route Tables page, find the router ID and click the name of the route instance.
  7. On the Route Entry List tab, click Custom.
  8. Click Publish next to the pod CIDR block. In this example, a CIDR block of 10.45.0.0/16 is used.
  9. In the Publish Route Entry dialog box, click OK.
  10. Repeat the preceding substeps to publish the pod route information about the ack-shanghai cluster to CEN.
  11. Verify whether the pod route information about the ack-hangzhou and ack-shanghai clusters is published to CEN.
    On the details page of the route table in the China (Hangzhou) region, click Dynamic on the Routes tab. You can view the route information of the pod CIDR block in the ack-shanghai cluster and the route information about the IPv4 CIDR block of vpc-shanghai-switch-1. On the details page of the route table in the China (Shanghai) region, you can also view the route information of the pod CIDR block in the ack-hangzhou cluster and the route information about the IPv4 CIDR block of vpc-hangzhou-switch-1. This indicates that the pod route information about the ack-hangzhou and ack-shanghai clusters is published to CEN.

Step 4: Add clusters to an ASM instance

Add the ack-hangzhou and ack-shanghai clusters that you created to an ASM instance.

  1. Log on to the ASM console.
  2. In the left-side navigation pane, choose Service Mesh > Mesh Management.
  3. On the Mesh Management page, find the ASM instance that you want to configure. Click the name of the ASM instance or click Manage in the Actions column.
  4. On the details page of the ASM instance, choose Cluster & Workload Management > Kubernetes Clusters in the left-side navigation pane. On the Kubernetes Clusters page, click Add.
  5. In the Add Cluster panel, select the ack-hangzhou cluster and click OK.
  6. In the Note dialog box, click OK.
  7. Repeat the preceding substeps to add the ack-shanghai cluster to the same ASM instance.

Step 5: Configure an ingress gateway in ASM

  1. View the ID of the ack-shanghai cluster.
    1. Log on to the ACK console.
    2. On the Clusters page, find the ack-shanghai cluster and click Details in the Actions column.
    3. On the Cluster Information page, click the Basic Information tab.
      In the Basic Information section, view the ID of the ack-shanghai cluster.
  2. Log on to the ASM console.
  3. In the left-side navigation pane, choose Service Mesh > Mesh Management.
  4. On the Mesh Management page, find the ASM instance that you want to configure. Click the name of the ASM instance or click Manage in the Actions column.
  5. On the details page of the ASM instance, click ASM Gateways in the left-side navigation pane. On the ASM Gateways page, click Create.
  6. On the Create page, select the ack-hangzhou cluster from the Cluster drop-down list, set the SLB Instance Type parameter to Internet Access, and then select a Server Load Balancer (SLB) instance from the Create SLB Instance drop-down list. Use the default values for other parameters. Then, click Create.
  7. On the ASM Gateways page, find a gateway named ingressgateway and click YAML in the Actions column.
  8. In the Edit panel, enter the ID of the ack-shanghai cluster and click OK. 
    spec:
  clusterIds:
    - ack-hangzhou cluster-id
    - ack-shanghai cluster-id

Step 6: Deploy the Bookinfo application

  1. Use kubectl to connect to the ack-hangzhou cluster. For more information, see Connect to ACK clusters by using kubectl.
  2. Create an ack-hangzhou-k8s.yaml file that contains the following content: 
    # Details service
apiVersion: v1
kind: Service
metadata:
  name: details
  labels:
    app: details
    service: details
spec:
  ports:
  - port: 9080
    name: http
  selector:
    app: details
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: bookinfo-details
  labels:
    account: details
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: details-v1
  labels:
    app: details
    version: v1
spec:
  replicas: 1
  selector:
    matchLabels:
      app: details
      version: v1
  template:
    metadata:
      labels:
        app: details
        version: v1
    spec:
      serviceAccountName: bookinfo-details
      containers:
      - name: details
        image: docker.io/istio/examples-bookinfo-details-v1:1.16.2
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 9080
        securityContext:
          runAsUser: 1000
---
# Ratings service
apiVersion: v1
kind: Service
metadata:
  name: ratings
  labels:
    app: ratings
    service: ratings
spec:
  ports:
  - port: 9080
    name: http
  selector:
    app: ratings
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: bookinfo-ratings
  labels:
    account: ratings
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: ratings-v1
  labels:
    app: ratings
    version: v1
spec:
  replicas: 1
  selector:
    matchLabels:
      app: ratings
      version: v1
  template:
    metadata:
      labels:
        app: ratings
        version: v1
    spec:
      serviceAccountName: bookinfo-ratings
      containers:
      - name: ratings
        image: docker.io/istio/examples-bookinfo-ratings-v1:1.16.2
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 9080
        securityContext:
          runAsUser: 1000
---
# Reviews service
apiVersion: v1
kind: Service
metadata:
  name: reviews
  labels:
    app: reviews
    service: reviews
spec:
  ports:
  - port: 9080
    name: http
  selector:
    app: reviews
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: bookinfo-reviews
  labels:
    account: reviews
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: reviews-v1
  labels:
    app: reviews
    version: v1
spec:
  replicas: 1
  selector:
    matchLabels:
      app: reviews
      version: v1
  template:
    metadata:
      labels:
        app: reviews
        version: v1
    spec:
      serviceAccountName: bookinfo-reviews
      containers:
      - name: reviews
        image: docker.io/istio/examples-bookinfo-reviews-v1:1.16.2
        imagePullPolicy: IfNotPresent
        env:
        - name: LOG_DIR
          value: "/tmp/logs"
        ports:
        - containerPort: 9080
        volumeMounts:
        - name: tmp
          mountPath: /tmp
        - name: wlp-output
          mountPath: /opt/ibm/wlp/output
        securityContext:
          runAsUser: 1000
      volumes:
      - name: wlp-output
        emptyDir: {}
      - name: tmp
        emptyDir: {}
---
# Productpage services
apiVersion: v1
kind: Service
metadata:
  name: productpage
  labels:
    app: productpage
    service: productpage
spec:
  ports:
  - port: 9080
    name: http
  selector:
    app: productpage
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: bookinfo-productpage
  labels:
    account: productpage
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: productpage-v1
  labels:
    app: productpage
    version: v1
spec:
  replicas: 1
  selector:
    matchLabels:
      app: productpage
      version: v1
  template:
    metadata:
      labels:
        app: productpage
        version: v1
    spec:
      serviceAccountName: bookinfo-productpage
      containers:
      - name: productpage
        image: docker.io/istio/examples-bookinfo-productpage-v1:1.16.2
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 9080
        volumeMounts:
        - name: tmp
          mountPath: /tmp
        securityContext:
          runAsUser: 1000
      volumes:
      - name: tmp
        emptyDir: {}
---
  3. Run the following command to deploy the Bookinfo application in the ack-hangzhou cluster: 
    kubectl apply -f ack-hangzhou-k8s.yaml
  4. Use kubectl to connect to the ack-shanghai cluster. For more information, see Connect to ACK clusters by using kubectl.
    Note When you use kubectl to connect to the ack-shanghai cluster, you must switch the kubeconfig of the ack-hangzhou cluster to that of the ack-shanghai cluster.
  5. Create an ack-shanghai.yaml file that contains the following content: 
    # Details service
apiVersion: v1
kind: Service
metadata:
  name: details
  labels:
    app: details
    service: details
spec:
  ports:
  - port: 9080
    name: http
  selector:
    app: details
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: bookinfo-details
  labels:
    account: details
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: details-v1
  labels:
    app: details
    version: v1
spec:
  replicas: 1
  selector:
    matchLabels:
      app: details
      version: v1
  template:
    metadata:
      labels:
        app: details
        version: v1
    spec:
      serviceAccountName: bookinfo-details
      containers:
      - name: details
        image: docker.io/istio/examples-bookinfo-details-v1:1.16.2
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 9080
        securityContext:
          runAsUser: 1000
---
# Ratings service
apiVersion: v1
kind: Service
metadata:
  name: ratings
  labels:
    app: ratings
    service: ratings
spec:
  ports:
  - port: 9080
    name: http
  selector:
    app: ratings
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: bookinfo-ratings
  labels:
    account: ratings
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: ratings-v1
  labels:
    app: ratings
    version: v1
spec:
  replicas: 1
  selector:
    matchLabels:
      app: ratings
      version: v1
  template:
    metadata:
      labels:
        app: ratings
        version: v1
    spec:
      serviceAccountName: bookinfo-ratings
      containers:
      - name: ratings
        image: docker.io/istio/examples-bookinfo-ratings-v1:1.16.2
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 9080
        securityContext:
          runAsUser: 1000
---
# Reviews service
apiVersion: v1
kind: Service
metadata:
  name: reviews
  labels:
    app: reviews
    service: reviews
spec:
  ports:
  - port: 9080
    name: http
  selector:
    app: reviews
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: bookinfo-reviews
  labels:
    account: reviews
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: reviews-v2
  labels:
    app: reviews
    version: v2
spec:
  replicas: 1
  selector:
    matchLabels:
      app: reviews
      version: v2
  template:
    metadata:
      labels:
        app: reviews
        version: v2
    spec:
      serviceAccountName: bookinfo-reviews
      containers:
      - name: reviews
        image: docker.io/istio/examples-bookinfo-reviews-v2:1.16.2
        imagePullPolicy: IfNotPresent
        env:
        - name: LOG_DIR
          value: "/tmp/logs"
        ports:
        - containerPort: 9080
        volumeMounts:
        - name: tmp
          mountPath: /tmp
        - name: wlp-output
          mountPath: /opt/ibm/wlp/output
        securityContext:
          runAsUser: 1000
      volumes:
      - name: wlp-output
        emptyDir: {}
      - name: tmp
        emptyDir: {}
---
# Productpage services
apiVersion: v1
kind: Service
metadata:
  name: productpage
  labels:
    app: productpage
    service: productpage
spec:
  ports:
  - port: 9080
    name: http
  selector:
    app: productpage
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: bookinfo-productpage
  labels:
    account: productpage
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: productpage-v1
  labels:
    app: productpage
    version: v1
spec:
  replicas: 1
  selector:
    matchLabels:
      app: productpage
      version: v1
  template:
    metadata:
      labels:
        app: productpage
        version: v1
    spec:
      serviceAccountName: bookinfo-productpage
      containers:
      - name: productpage
        image: docker.io/istio/examples-bookinfo-productpage-v1:1.16.2
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 9080
        volumeMounts:
        - name: tmp
          mountPath: /tmp
        securityContext:
          runAsUser: 1000
      volumes:
      - name: tmp
        emptyDir: {}
---
  6. Run the following command to deploy the Bookinfo application in the ack-shanghai cluster: 
    kubectl apply -f ack-shanghai.yaml
  7. Use kubectl to connect to the ASM instance. For more information, see Use kubectl to connect to an ASM instance.
    Note When you use kubectl to connect to the ASM instance, you must switch the kubeconfig of the ack-shanghai cluster to that of the ASM instance.
  8. Create an asm.yaml file that contains the following content: 
    apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
  name: bookinfo-gateway
spec:
  selector:
    istio: ingressgateway # use istio default controller
  servers:
  - port:
      number: 80
      name: http
      protocol: HTTP
    hosts:
    - "*"
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: bookinfo
spec:
  hosts:
  - "*"
  gateways:
  - bookinfo-gateway
  http:
  - match:
    - uri:
        exact: /productpage
    - uri:
        prefix: /static
    - uri:
        exact: /login
    - uri:
        exact: /logout
    - uri:
        prefix: /api/v1/products
    route:
    - destination:
        host: productpage
        port:
          number: 9080
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: productpage
spec:
  host: productpage
  subsets:
  - name: v1
    labels:
      version: v1
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: reviews
spec:
  host: reviews
  subsets:
  - name: v1
    labels:
      version: v1
  - name: v2
    labels:
      version: v2
  - name: v3
    labels:
      version: v3
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: ratings
spec:
  host: ratings
  subsets:
  - name: v1
    labels:
      version: v1
  - name: v2
    labels:
      version: v2
  - name: v2-mysql
    labels:
      version: v2-mysql
  - name: v2-mysql-vm
    labels:
      version: v2-mysql-vm
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: details
spec:
  host: details
  subsets:
  - name: v1
    labels:
      version: v1
  - name: v2
    labels:
      version: v2
---
  9. Run the following command to create a routing rule in the ASM instance: 
    kubectl apply -f asm.yaml
  10. Verify whether the Bookinfo application is deployed.
    1. Log on to the ACK console.
    2. In the left-side navigation pane of the ACK console, click Clusters.
    3. On the Clusters page, find the ack-hangzhou cluster and click Details in the Actions column.
    4. In the left-side navigation pane of the details page, choose Network > Services
    5. At the top of the Services page, select istio-system from the Namespace drop-down list. Find an ingress gateway named istio-ingressgateway and view the IP address whose port is 80 in the External Endpoint column.
    6. Enter <IP address of the ingress gateway>/productpage in the address bar of your browser.
      Refresh the page multiple times. The following images alternately appear on the screen. review1review1

Step 7: Use the cross-region traffic distribution and failover features

Configure cross-region traffic distribution

  1. Log on to the ASM console.
  2. In the left-side navigation pane, choose Service Mesh > Mesh Management.
  3. On the Mesh Management page, find the ASM instance that you want to configure. Click the name of the ASM instance or click Manage in the Actions column.
  4. On the details page of the ASM instance, choose ASM Instance > Base Information in the left-side navigation pane. On the Basic Information page, click Settings.
  5. On the Basic Information page, click Enable locality traffic distribution on the right of Locality-Failover.
    Note If you have enabled cross-region failover, you must disable cross-region failover before you can enable cross-region traffic distribution.
  6. In the Locality-Traffic-Distribution dialog box, set the Policy parameter to cn-hangzhou and click New Policy.
  7. Click the Show icon icon and then the Create icon icon. Set the To parameter to cn-hangzhou and the Weight parameter to 90%.
  8. Click the Create icon icon, set the To parameter to cn-shanghai and the Weight parameter to 10%, and then click Submit.
  9. Run the following command to request the Bookinfo application 10 times to verify whether the cross-region traffic distribution is successful: 
    for ((i=1;i<=10;i++));do curl http://<Ingress gateway endpoint of port 80 in the ack-hangzhou cluster>/productpage 2>&1grep full.stars;done

    Expected output:

    <!-- full stars: -->
<!-- full stars: -->

    You can find that 10 access requests are made and two rows of full stars output are returned. This indicates that 9 of the 10 requests are routed to the v1 reviews service in the ack-hangzhou cluster and 1 request is routed to the v2 reviews service in the ack-shanghai cluster. Traffic is routed to different clusters based on the weights of the clusters.

Configure cross-region failover

  1. Disable the reviews service in the ack-hangzhou cluster.
    1. Log on to the ACK console.
    2. In the left-side navigation pane of the ACK console, click Clusters.
    3. In the left-side navigation pane of the details page, choose Workloads > Deployments.
    4. On the Deployments page, set the Namespace parameter to default, find reviews-v1, and then click Scale in the Actions column.
    5. In the Scale dialog box, set the Desired Number of Pods parameter to 0 and click OK.
  2. Configure a destination rule.
    Configure a destination rule. If the reviews service cannot be requested within 1 second, the reviews service will be ejected for 1 minute.
    1. Log on to the ASM console.
    2. In the left-side navigation pane, choose Service Mesh > Mesh Management.
    3. On the Mesh Management page, find the ASM instance that you want to configure. Click the name of the ASM instance or click Manage in the Actions column.
    4. On the details page of the ASM instance, choose Traffic Management > DestinationRule in the left-side navigation pane.
    5. On the DestinationRule page, find the reviews service and click YAML in the Actions column.
    6. In the Edit panel, copy the following content to the code editor and click OK: 
      spec:
  ......
  trafficPolicy:
    connectionPool:
      http:
        maxRequestsPerConnection: 1
    outlierDetection:
      baseEjectionTime: 1m
      consecutive5xxErrors: 1
      interval: 1s
      • maxRequestsPerConnection: specifies the maximum number of requests per connection.
      • baseEjectionTime: specifies the minimum ejection duration.
      • consecutive5xxErrors: specifies the number of consecutive errors.
      • interval: specifies the time interval for ejection analysis.
  3. Enable cross-region failover.
    1. On the details page of the ASM instance, choose ASM Instance > Base Information in the left-side navigation pane.
    2. On the Basic Information page, click Enable Locality-Failover on the right of Locality-Failover.
      Note If you have enabled cross-region traffic distribution, you must disable cross-region traffic distribution before you can enable cross-region failover.
    3. In the Locality-Failover dialog box, set the Failover parameter to cn-hangzhou if the From parameter is set to cn-shanghai. Set the Failover parameter to cn-shanghai if the From parameter is set to cn-hangzhou. Then, click Submit.
  4. Run the following command to request the Bookinfo application 10 times and record the number of successful routes to the v2 reviews service: 
    for ((i=1;i<=10;i++));do curl http://<Ingress gateway endpoint of port 80 in the ack-hangzhou cluster>/productpage 2>&1grep full.stars;donewc -l

    Expected output:

    20

    You can find that 10 access requests are made and 20 rows of results are returned. This is because a two-row result that contains full stars is returned each time a route to the v2 reviews service succeeds. This indicates that all 10 requests are routed to the v2 reviews service in the ack-shanghai cluster, and the cross-region failover is successful.

FAQ

I connect the VPCs of Kubernetes clusters by using CEN. However, an error message is displayed when I add the clusters to the ASM instance. What do I do?

If your clusters reside in different regions, you must purchase a cross-region data transfer plan and configure valid settings for cross-region data transfer when you connect the VPCs of the clusters by using CEN. Otherwise, the ASM instance fails to connect to the clusters on the data plane. In this case, you fail to add the clusters to the ASM instance.

To resolve this issue, you need to reconfigure valid settings for cross-region data transfer in the CEN console to connect the VPCs of the clusters by using CEN. For more information, see Step 2: Use CEN to implement cross-region VPC communication.