A production web application runs on four EC2 instances behind an Elastic Load Balancer and is managed by AWS Elastic Beanstalk. A developer needs to update the platform version (Node.js) and deploy new application code for testing without any downtime. Which deployment approach satisfies these requirements?

An immutable update ensures zero downtime and easy rollback by deploying the new application version to an entirely new set of EC2 instances. Once these new instances pass health checks, the Elastic Load Balancer seamlessly shifts traffic to them. This approach prevents issues from affecting the live production environment during deployment and allows for a quick rollback by simply terminating the new instances if problems arise. Cloning the environment and swapping URLs is a valid strategy for major platform upgrades but is more involved than necessary for a typical code deployment. All-at-once deployment causes downtime and high risk. Rolling deployments can still introduce issues to a portion of the live environment during the update process.