Let's put k8s aside. If I had a complex system needing say five boxes, I might be able to admin it well - startup, shutdown, upgrade - if there was a simple orc

Let's put k8s aside. If I had a complex system needing say five boxes, I might be able to admin it well - startup, shutdown, upgrade - if there was a simple orchestrated glue between the boxes e.g. on the control box 1, run a script to start daemons/pids on boxes 2, 5 which blocks until success or failure ... something more sophisticated than remsh/ssh. This is old school, but it's just a script or three.