Well at the VM level live migration and vmotion have been around for a while. I've watched a VM get migrated while ping is running without missing a single packet.
CRIU is used lots of places for Linux processes but in my experience is far more low level and finicky and it tends to do things that require root permissions. It's used in production, but I would be shocked if, for example, someone made it so k8s could just live migrate any pod with CRIU.
Just think of the possible ways apps that might break if you changed their hostname or pid out from under them. And that's not even including stuff like connections to localhost or shared memory.
CRIU is used lots of places for Linux processes but in my experience is far more low level and finicky and it tends to do things that require root permissions. It's used in production, but I would be shocked if, for example, someone made it so k8s could just live migrate any pod with CRIU.
Just think of the possible ways apps that might break if you changed their hostname or pid out from under them. And that's not even including stuff like connections to localhost or shared memory.