What is the correct action to take when employing a blue/green deployment strategy in Google Kubernetes Engine?

In a blue/green deployment strategy, the primary goal is to minimize downtime and reduce the risk associated with new application releases. This is accomplished by running two identical environments, allowing one (blue) to serve production traffic while the other (green) is used for staging a new version of the application.

Updating the service selector for the blue version is a logical action because once the new environment (green) has been fully tested and is confirmed to be stable, the traffic can be switched from the blue deployment to the green deployment. However, by maintaining the blue deployment in a ready state and updating its selector to point to the new version in the green deployment, you ensure that rollbacks can be performed seamlessly if any issues arise post-deployment.

This approach allows you to hold the current stable version (blue) while preparing the new version (green) for production. If there’s confidence in the green deployment after testing, the traffic can be switched over to it, officially making it the new live version.

The other options do not align effectively with the blue/green strategy. For instance, simply updating the version of the blue deployment or changing the service selector to point to the green deployment without verification can lead to instability or errors in production. It's also crucial