You want to deploy a serverless app and route a small percentage of production traffic to a new version for testing. What should you do?

Cloud Run is ideal for serverless containerized applications and natively supports traffic splitting (gradual rollouts) for A/B testing or canary deployments. This allows you to route a small percentage of traffic to a new version without impacting the majority of users. GKE with Anthos Service Mesh is a powerful option but is more complex and not strictly serverless. Cloud Functions are serverless but lack built-in traffic splitting capabilities; including a version in the name doesn't facilitate traffic routing. App Engine allows multiple versions, but traffic splitting is typically done at the service level, not as granularly or as seamlessly as Cloud Run's gradual rollouts for containerized apps.