Getting Started - Istio¶
- Kubernetes cluster with Istio installed
See the environment setup guide for Istio on how to setup a local minikube environment with Istio
1. Deploy the Rollout, Services, Istio VirtualService, and Istio Gateway¶
When Istio is used as the traffic router, the Rollout canary strategy must define the following mandatory fields:
apiVersion: argoproj.io/v1alpha1 kind: Rollout metadata: name: rollouts-demo spec: strategy: canary: # Reference to a Service which the controller updates to point to the canary ReplicaSet canaryService: rollouts-demo-canary # Reference to a Service which the controller updates to point to the stable ReplicaSet stableService: rollouts-demo-stable trafficRouting: istio: virtualService: # Reference to a VirtualService which the controller updates with canary weights name: rollouts-demo-vsvc routes: - primary # optional if there is a single route in VirtualService, required otherwise ...
The VirtualService and route referenced in
trafficRouting.istio.virtualService is required
to have a HTTP route which splits between the stable and canary Services, referenced in the rollout.
In this guide, those Services are named:
respectively. The weight values for these services used should be initially set to 100% stable,
and 0% on the canary. During an update, these values will be modified by the controller.
apiVersion: networking.istio.io/v1alpha3 kind: VirtualService metadata: name: rollouts-demo-vsvc spec: gateways: - rollouts-demo-gateway hosts: - rollouts-demo.local http: - name: primary # Should match spec.strategy.canary.trafficRouting.istio.virtualService.routes route: - destination: host: rollouts-demo-stable # Should match spec.strategy.canary.stableService weight: 100 - destination: host: rollouts-demo-canary # Should match spec.strategy.canary.canaryService weight: 0
Run the following commands to deploy:
- A Rollout
- Two Services (stable and canary)
- An Istio VirtualService
- An Istio Gateway
kubectl apply -f https://raw.githubusercontent.com/argoproj/argo-rollouts/master/docs/getting-started/istio/rollout.yaml kubectl apply -f https://raw.githubusercontent.com/argoproj/argo-rollouts/master/docs/getting-started/istio/services.yaml kubectl apply -f https://raw.githubusercontent.com/argoproj/argo-rollouts/master/docs/getting-started/istio/virtualsvc.yaml kubectl apply -f https://raw.githubusercontent.com/argoproj/argo-rollouts/master/docs/getting-started/istio/gateway.yaml
After applying the manifests you should see the following rollout, services, virtualservices, and gateway resources in the cluster:
$ kubectl get ro NAME DESIRED CURRENT UP-TO-DATE AVAILABLE rollouts-demo 1 1 1 1 $ kubectl get svc NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE rollouts-demo-canary ClusterIP 10.103.146.137 <none> 80/TCP 37s rollouts-demo-stable ClusterIP 10.101.158.227 <none> 80/TCP 37s $ kubectl get virtualservice NAME GATEWAYS HOSTS AGE rollouts-demo-vsvc [rollouts-demo-gateway] [rollouts-demo.local] 54s $ kubectl get gateway NAME AGE rollouts-demo-gateway 71s
kubectl argo rollouts get rollout rollouts-demo
2. Perform an update¶
Update the rollout by changing the image, and wait for it to reached the paused state.
kubectl argo rollouts set image rollouts-demo rollouts-demo=argoproj/rollouts-demo:yellow kubectl argo rollouts get rollout rollouts-demo
At this point, both the canary and stable version of the Rollout are running, with 5% of the traffic directed to the canary. To understand how this works, inspect the VirtualService which the Rollout was referencing. When looking at the VirtualService, we see that the route destination weights have been modified by the controller to reflect the current weight of the canary.
apiVersion: networking.istio.io/v1beta1 kind: VirtualService metadata: name: rollouts-demo-vsvc namespace: default spec: gateways: - rollouts-demo-gateway hosts: - rollouts-demo.local http: - name: primary route: - destination: host: rollouts-demo-stable weight: 95 - destination: host: rollouts-demo-canary weight: 5
As the Rollout progresses through steps, the HTTP route destination weights will be adjusted to match the current setWeight of the steps.