The part that stands out is that you are optimizing for warm state instead of cold boot. That feels right for dev shells. If the workload is repeated short lived environments, template fork time matters more than booting a minimal kernel fast. How do you handle template drift over time? Do you periodically rebuild and re-warm from scratch, or can you patch a warm template in place without losing the memory-sharing gains?

Thanks for sharing! I'm not sure your table under Why Clone is quite correct.

10x 512MB idle VMs should not take 5GB on Firecracker if they are started from snapshots since the 512MB memory file is mmap'ed with MAP_PRIVATE so is copy on write.

Firecracker has diff snapshots: https://github.com/firecracker-microvm/firecracker/blob/main...