Customize Istio

You can customize the Verrazzano Istio component using settings in the Verrazzano custom resource.

The following table describes the fields in the Verrazzano custom resource pertaining to the Istio component.

Path to Field Description
spec.components.istio.egress.kubernetes.replicas The number of pods to replicate. The default is 2 for the prod profile and 1 for all other profiles.
spec.components.istio.egress.kubernetes.affinity The pod affinity definition expressed as a standard Kubernetes affinity definition. The default configuration spreads the Istio gateway pods across the available nodes. 
spec:
  components:
    istio:
      egress:
        kubernetes:
          affinity:
            podAntiAffinity:
              preferredDuringSchedulingIgnoredDuringExecution:
                - weight: 100
                  podAffinityTerm:
                    labelSelector:
                      matchExpressions:
                        - key: app
                          operator: In
                          values:
                            - istio-egressgateway
                    topologyKey: kubernetes.io/hostname
spec.components.istio.ingress.kubernetes.replicas The number of pods to replicate. The default is 2 for the prod profile and 1 for all other profiles.
spec.components.istio.ingress.kubernetes.affinity The pod affinity definition expressed as a standard Kubernetes affinity definition. The default configuration spreads the Istio gateway pods across the available nodes. 
spec:
  components:
    istio:
      ingress:
        kubernetes:
          affinity:
            podAntiAffinity:
              preferredDuringSchedulingIgnoredDuringExecution:
                - weight: 100
                  podAffinityTerm:
                    labelSelector:
                      matchExpressions:
                        - key: app
                          operator: In
                          values:
                            - istio-ingressgateway
                    topologyKey: kubernetes.io/hostname

The following example customizes a Verrazzano prod profile as follows:

  • Increases the replicas count to 3 for istio-ingressgateway and istio-egressgateway
  • Changes the podAffinity configuration to use requiredDuringSchedulingIgnoredDuringExecution for istio-ingressgateway and istio-egressgateway 
    apiVersion: install.verrazzano.io/v1beta1
kind: Verrazzano
metadata:
  name: example-verrazzano
spec:
  profile: prod
  components:
    istio:
      overrides:
      - values:
          apiVersion: install.istio.io/v1alpha1
          kind: IstioOperator
          spec:
            components:
              egressGateways:
                - enabled: true
                  k8s:
                    affinity:
                      podAntiAffinity:
                        requiredDuringSchedulingIgnoredDuringExecution:
                          - podAffinityTerm:
                              labelSelector:
                                matchExpressions:
                                  - key: app
                                    operator: In
                                    values:
                                      - istio-egressgateway
                              topologyKey: kubernetes.io/hostname
                            weight: 100
                    replicaCount: 3
                  name: istio-egressgateway
              ingressGateways:
                - enabled: true
                  k8s:
                    affinity:
                      podAntiAffinity:
                        requiredDuringSchedulingIgnoredDuringExecution:
                          - podAffinityTerm:
                              labelSelector:
                                matchExpressions:
                                  - key: app
                                    operator: In
                                    values:
                                      - istio-ingressgateway
                              topologyKey: kubernetes.io/hostname
                            weight: 100
                    replicaCount: 3
                    service:
                      type: LoadBalancer
                  name: istio-ingressgateway