Blue/green deployment with micro services and DNS
You should have 3 names when you're willing to do a blue/green deployment.

Two set of names, one for blue, one for green, which will works as is, and a production entrypoint which will point to either the blue name or green name.

The point of a blue/green deployment is to be able to test the full deploy before switching the clients entry point, so your services calls themselves don't have to use the entry point name itself.