Ah. VMware does something similar for hot provisioning VMs from a point in time memory snapshot.
So you guys boot the image in the background, then capture a memory dump of it so you can quickly launch VMs from that snapshot? Or you boot the VMs the traditional way the first time, and then just suspend them when not in use?
We do even more, we take snapshots as the "Layerfile" runs - this basically lets you merge the memory dump semantics you mention with the interface of Docker.
Also, we monitor which files are read by any step in the process, and let you skip setup chunks that don't need to run (i.e., installing libraries) without needing to micromanage what files you copy into the staging server.
Man that sounds cool. I don't have any use for something like that, but I would love to see it opensourced to play with it (which I assume you guys won't be doing anytime soon)
So you guys boot the image in the background, then capture a memory dump of it so you can quickly launch VMs from that snapshot? Or you boot the VMs the traditional way the first time, and then just suspend them when not in use?