You are thinking in right direction. Ultra small but critical service like "is_even" and combining it with reliability of a kubernetes cluster, that is genius level stuff.
How many have even setup a Kubernetes cluster manually?
They use a Kubernetes “distribution” that adds another layer of automation on top of that!!!
The day is near where “is_even” will be decomposed into multiple containers, with an added caching layer, and extensible authentication layer.
You might hate/enjoy this then: https://andreasjhkarlsson.github.io/jekyll/update/2023/12/27...
Have people taken "Function-as-a-Service" too literally and done the equivalent of moving "is_even" into an AWS Lambda? Or maybe have a dedicated "is_even" nano-service with its own Kubernetes cluster?