‘Probably the biggest is: how do you deal with the migration of legacy things? At Bustle we ended up mostly re-architecting our entire platform around serverless, and so that’s one option, but certainly not available to everybody. But even then, the first time we launched a serverless service, we brought down all of our Redis instances — because Lambda spun up all these containers and we hit connection limits that you would never expect to hit in a normal app.
‘So if you’ve got something sitting on a mainframe somewhere that is used to only having 20 connections and then you moved over some upstream service to Lambda and suddenly it has 10,000 connections instead of 20. You’ve got a problem. If you’ve bought into service-oriented architecture as a whole over the last four or five years, then you might have a better time, because you can say “Well, all these things do is talk to each other via an API, so we can replace a single service with serverless functions.”’
Original source: Serverless at Bustle