All live migration systems basically follow the same pattern https://cloud.google.com/compute/docs/instances/live-migrati...

And as others have mentioned upthread, Mosix was an extension to Linux that also implemented fork() in such a way that the child could be local or remote with file handles retained across the cluster. We had a Linux lan party when I was in college and managed to scrape together a Mosix cluster across a bunch of machines.

Ignore the uncreative pedants.