There is a specific way to turn a slow database into a total outage, and it fits in one line of YAML.
You point your Kubernetes liveness probe at an endpoint that checks the database. The database gets slow. The probe times out. Kubernetes concludes the container is wedged and restarts it. It restarts every replica, all at once, because they all failed for the same reason at the same time. What was a degraded service — slow, but serving — is now nothing at all, and the restarts keep the database busy enough that it cannot recover.
I have never met an engineer who did this on purpose. It happens because liveness and readiness probes look interchangeable in the documentation, and the difference only becomes obvious at three in the morning.
That is exactly why it is a good interview question.
Naming tools is not the same as knowing what to do with them
