Customize Istio

Customize Istio Gateways

You can customize 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/v1alpha1
kind: Verrazzano
metadata:
  name: example-verrazzano
spec:
  profile: prod
  components:
    istio:
      ingress:
        kubernetes:
          replicas: 3
          affinity:
            podAntiAffinity:
              requiredDuringSchedulingIgnoredDuringExecution:
                - weight: 25
                    labelSelector:
                      matchExpressions:
                        - key: app
                          operator: In
                          values:
                            - istio-ingressgateway
                    topologyKey: kubernetes.io/hostname
      egress:
        kubernetes:
          replicas: 3
          affinity:
            podAntiAffinity:
              requiredDuringSchedulingIgnoredDuringExecution:
                - labelSelector:
                    matchExpressions:
                      - key: app
                        operator: In
                        values:
                          - istio-egressgateway
                  topologyKey: kubernetes.io/hostname