A legacy billing monolith must be replaced over the next year. You want a growing share of invoice requests sent to new Cloud Run services while the monolith keeps serving everything else, and you need to be able to roll a route back quickly. Which approach and traffic mechanism fit?
Show answer and explanation
Answer: A
The strangler pattern replaces a monolith one capability at a time. A gateway or HTTP(S) load balancer sends chosen paths to the new Cloud Run services while the monolith handles the rest, and reverting a route is a configuration change rather than a redeployment.
Why the other options are wrong
- B. A big-bang cutover moves all traffic at once, so there is no gradual share, and rolling back means reversing an entire system change under pressure.
- C. Dropping the database before replacement destroys data that the monolith and the new services depend on, and it provides no routing at all.
- D. Cloud Scheduler triggers jobs on timers and is not a request router for live invoice traffic, so it cannot split or steer user requests.