What about service discovery? What if you need to put power your node down for maintenance? What if your app goes crazy and consumes so much memory it OOMs some other services? Reliable, multi-service deployments ARE HARD and always be regardless what tech you use to achive it. Of course you can use Ansible and do it old-school way and wast lots of underutilised VMs and custom idempotent scripts. But K8S solves many of challenges in a standardised, data-driven way. It has steep learning curve but once learned, all resources/limits are properly set, logging in place, etc, it works nicely.