Traffic Routing with Istio

FEATURE STATE: Kruise Rollout v0.5.0

This page is a demo to show how to utilize Kruise Rollout to do traffic routing with Istio.

A Complete Release Process

Deploy deployment workload-demo and service service-demo

apiVersion: v1
kind: Service
metadata:
  name: service-demo
spec:
  ports:
  - port: 80
    name: http
  selector:
    app: nginx
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: workload-demo
  labels:
    app: nginx
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx
        env:
        - name: version
          value: base
        ports:
        - containerPort: 80

Deploy VirtualService vs-demo which routes traffic to service-demo

apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
  name: vs-demo
spec:
  gateways:
  - simple-gateway
  hosts:
    - "*"
  http:
  - route:
      - destination:
          host: service-demo

Deploy Rollout rollouts-demo

apiVersion: rollouts.kruise.io/v1beta1
kind: Rollout
metadata:
  name: rollouts-demo
spec:
  workloadRef:
    apiVersion: apps/v1
    kind: Deployment
    name: workload-demo
  strategy:
    canary:
      steps:
      - replicas: 1
        matches:
        - headers:
          - type: Exact
            name: version
            value: canary
      - traffic: 50%
        replicas: 50%
      - traffic: 80%
        replicas: 80%
      trafficRoutings:
      - service: mocka
        customNetworkRefs:
        - apiVersion: networking.istio.io/v1alpha3
          kind: VirtualService
          name: vs-demo

When you apply a new revision for workload-demo, Kruise Rollout will modify configuration of VirtualService to comply with release strategies:

• A new canary Deployment will be created, and its replicas is 1. Traffic with header version=canary will be routed to the new-version pods while other traffic will be routed to stable-version pods.
• Update the replicas of canary Deployment to "50%" of workload-demo and route 20% of traffic to new-version pods.
• Update the replicas of canary Deployment to "80%" of workload-demo and route 80% of traffic to new-version pods.

Upgrade deployment workload-demo

Run the following command to update env version: base to version: canary to start release.

$ kubectl patch deployment workload-demo -p \
'{"spec":{"template":{"spec":{"containers":[{"name":"nginx", "env":[{"name":"version", "value":"canary"}]}]}}}}'

Wait a while, Kruise Rollout will do the following work for you:

• Pause the base Deployment.
• Create a new Deployment with env version: canary.
• Create a new Service service-demo-canary to route traffic to new-version pods.
• Update VirtualService vs-demo to do traffic routing.

After the first release step is done, check VirtualService vs-demo and you will see:

apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
  annotations:
    rollouts.kruise.io/original-spec-configuration: '{"spec":{"gateways":["simple-gateway"],"hosts":["*"],"http":[{"route":[{"destination":{"host":"service-demo"}}]}]},"annotations":{"kubectl.kubernetes.io/last-applied-configuration":"{\"apiVersion\":\"networking.istio.io/v1beta1\",\"kind\":\"VirtualService\",\"metadata\":{\"annotations\":{},\"name\":\"vs-demo\",\"namespace\":\"default\"},\"spec\":{\"gateways\":[\"simple-gateway\"],\"hosts\":[\"*\"],\"http\":[{\"route\":[{\"destination\":{\"host\":\"service-demo\"}}]}]}}\n"}}'
  name: vs-demo
spec:
  gateways:
  - simple-gateway
  hosts:
  - '*'
  http:
  # route traffic with header version=canary to new-version pods
  - match:
    - headers:
        version:
          exact: canary
    route:
    - destination:
        host: service-demo-canary
  - route:
    - destination:
        host: service-demo

Run kubectl-kruise rollout approve rollout/rollouts-demo -n default to start second release step. After the second release step is done, check VirtualService vs-demo and you will see:

apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
  annotations:
    rollouts.kruise.io/original-spec-configuration: '{"spec":{"gateways":["simple-gateway"],"hosts":["*"],"http":[{"route":[{"destination":{"host":"service-demo"}}]}]},"annotations":{"kubectl.kubernetes.io/last-applied-configuration":"{\"apiVersion\":\"networking.istio.io/v1beta1\",\"kind\":\"VirtualService\",\"metadata\":{\"annotations\":{},\"name\":\"vs-demo\",\"namespace\":\"default\"},\"spec\":{\"gateways\":[\"simple-gateway\"],\"hosts\":[\"*\"],\"http\":[{\"route\":[{\"destination\":{\"host\":\"service-demo\"}}]}]}}\n"}}'
  name: vs-demo
spec:
  gateways:
  - simple-gateway
  hosts:
  - '*'
  http:
  - route:
    - destination:
        host: service-demo
      weight: 50
    - destination:
        host: service-demo-canary
      weight: 50 # route 50% traffic to new-version pods

Run kubectl-kruise rollout approve rollout/rollouts-demo -n default to start third release step. After the third release step is done, check VirtualService vs-demo and you will see:

apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
  annotations:
    rollouts.kruise.io/original-spec-configuration: '{"spec":{"gateways":["simple-gateway"],"hosts":["*"],"http":[{"route":[{"destination":{"host":"service-demo"}}]}]},"annotations":{"kubectl.kubernetes.io/last-applied-configuration":"{\"apiVersion\":\"networking.istio.io/v1beta1\",\"kind\":\"VirtualService\",\"metadata\":{\"annotations\":{},\"name\":\"vs-demo\",\"namespace\":\"default\"},\"spec\":{\"gateways\":[\"simple-gateway\"],\"hosts\":[\"*\"],\"http\":[{\"route\":[{\"destination\":{\"host\":\"service-demo\"}}]}]}}\n"}}'
  name: vs-demo
spec:
  gateways:
  - simple-gateway
  hosts:
  - '*'
  http:
  - route:
    - destination:
        host: service-demo
      weight: 20
    - destination:
        host: service-demo-canary
      weight: 80 # route 80% traffic to new-version pods

Run kubectl-kruise rollout approve rollout/rollouts-demo -n default to complete the release, Kruise Rollout will do some finalising work:

• Delete the canary Deployment.
• Delete the canary Service service-demo-canary.
• Resume the base Deployment.
• Restore the VirtualService vs-demo.

After that, the release is done and your are ready to use the new-version service.