Refactoring across the call stack is orders of magnitude easier than refactoring across a socket.
Sacrificial or not, you can still write the Monolith as "Service Oriented", just that boundary is the call stack. Especially if you're comfortable with IoC and DI.
Building on the latter I've had success with that. Stubbing out hardcoded concepts that I know will come from a as-yet-unwritten service in the future. Then you start pushing those hardcoded things "down and out"; e.g. it was hardcoded in App A, but now App A requests it from App B, but App B just has the hardcoded thing.
Refactoring across the call stack is orders of magnitude easier than refactoring across a socket.
Sacrificial or not, you can still write the Monolith as "Service Oriented", just that boundary is the call stack. Especially if you're comfortable with IoC and DI.
Building on the latter I've had success with that. Stubbing out hardcoded concepts that I know will come from a as-yet-unwritten service in the future. Then you start pushing those hardcoded things "down and out"; e.g. it was hardcoded in App A, but now App A requests it from App B, but App B just has the hardcoded thing.