Depending on your level of expertise in this area, you may wonder why Istio’s support for canary deployment is even needed, given that platforms like Kubernetes already provide a way to do version rollout and canary deployment. Problem solved, right? Well, not exactly. Although doing a rollout this way works in simple cases, it’s very limited, especially in large scale cloud environments receiving lots of (and especially varying amounts of) traffic, where autoscaling is needed.

apiVersion: v1
kind: ConfigMap
metadata:
  name: gw-options
data:
  horizontalPodAutoscaler: |
    spec:
      minReplicas: 2
      maxReplicas: 2

  deployment: |
    metadata:
      annotations:
        additional-annotation: some-value
    spec:
      replicas: 4
      template:
        spec:
          containers:
          - name: istio-proxy
            resources:
              requests:
                cpu: 1234m

  service: |
    spec:
      ports:
      - "\$patch": delete
        port: 15021