Migrating to Rollouts

Migrating to Argo Rollouts involves converting an existing Deployment resource, to a Rollout resource.

When converting a Deployment to a Rollout, it involves changing three fields:

1. Replacing the apiVersion from apps/v1 to argoproj.io/v1alpha1
2. Replacing the kind from Deployment to Rollout
3. Replacing the deployment strategy with a blue-green or canary strategy

Below is an example of a Rollout resource using the canary strategy.

apiVersion: argoproj.io/v1alpha1  # Changed from apps/v1
kind: Rollout                     # Changed from Deployment
metadata:
  name: rollouts-demo
spec:
  selector:
    matchLabels:
      app: rollouts-demo
  template:
    metadata:
      labels:
        app: rollouts-demo
    spec:
      containers:
      - name: rollouts-demo
        image: argoproj/rollouts-demo:blue
        ports:
        - containerPort: 8080
  strategy:
    canary:                        # Changed from rollingUpdate or recreate
      steps:
      - setWeight: 20
      - pause: {}

Other Considerations

When migrating a Deployment which is already serving live production traffic, a Rollout should run next to the Deployment before deleting the Deployment. Not following this approach might result in downtime. It also allows for the Rollout to be tested before deleting the original Deployment.