Comment by sofixa
For a cool practical example, check out Nomad's (flexible workload orchestrator) exec2 task driver: https://github.com/hashicorp/nomad-driver-exec2
It allows running non/semi-trusted workloads with isolation. Pretty useful to onboard applications into a proper scheduler with all bells and whistles without having to containerise, but still with decent levels of isolation between them.
I switched away from Nomad when HashiCorp moved from FOSS licenses to the BSL. But man, I do miss its simplicity.