Chapter 5. Migrating gateways

Procedure

1. Run the following command to label the gateway namespace to ensure that gateway injection is enabled from the new mesh and add the maistra.io/ignore-namespace: "true" label:

   $ oc label namespace <gateway_namespace> istio.io/rev=<istio_revision_name> maistra.io/ignore-namespace="true"

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   1. Remove the istio-injection=enabled label, if needed.

2. Deploy a canary gateway by using the following example:

   Example YAML for canary gateway

   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: istio-ingressgateway-canary
     namespace: istio-ingress 

   1

   
   spec:
      selector:
        matchLabels:
          istio: ingressgateway 

   2

   
      template:
        metadata:
          annotations:
            inject.istio.io/templates: gateway
          labels:
            istio: ingressgateway
            istio.io/rev: canary 

   3

   
        spec:
          containers:
          - name: istio-proxy
            image: auto

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   1

   Your Deployment resource must be in in the same namespace as your existing gateway.

   2

   Your spec.selector.matchlabels.istio parameter must match your existing gateway service selector.

   3

   Set your OpenShift Service Mesh 3.0 control plane revision as the value of the istio.io/rev label.

3. Ensure that the new gateway deployment is running with the new revision and is handling requests:

   1. Check that pods are running and in the Ready status.

   2. Check that the gateway is running the new revision by running the following command:

      $ istioctl ps -n istio-ingress

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   3. Test a sample route through the gateway.

4. Gradually shift traffic between deployments:

   1. Increase replicas for new gateway by running the following command:

      $ oc scale -n istio-ingress deployment/<new_gateway_deployment> --replicas <new_number_of_replicas>

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   2. Decrease replicas for old gateway by running the following command:

      $ oc scale -n istio-ingress deployment/<old_gateway_deployment> --replicas <new_number_of_replicas>

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   3. Repeat this process, incrementally adjusting replica counts until the new gateway handles all traffic to the gateway Service.

Procedure

1. Run the following command to label the gateway namespace to ensure that gateway injection is enabled from the new mesh and add the maistra.io/ignore-namespace: "true" label:

   $ oc label namespace <gateway_namespace> istio.io/rev=<istio_revision_name> maistra.io/ignore-namespace="true"

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   1. Remove the istio-injection=enabled label, if needed.

2. Restart the gateway deployment by running the following command:

   $ oc -n ${app_namespace} rollout restart deployment ${gateway_name}

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Verification

1. Check that the gateway is running the new revision by running the following command:

   $ istioctl ps -n istio-ingress

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2. Test application-specific routes.