[packetlost]

I mean, Vagrant was basically docker before docker. People used it. But it turns out the overhead over booting a full VM + kernel adds latency which is undesirable for development workloads. The techniques used by firecracker could be used, but I suspect the overhead of allocating a namespace and loading a process will always be less than even restoring from a frozen VM, so I wouldn't hold my breath on it swinging back in VM's direction for developer workloads ever.

[yjftsjthsd-h]

It would be interesting to see a microvm (kata/firecracker/etc.) version of vagrant. And open source, of course. I can't see any technical reason why it would be particularly difficult.

[packetlost]

I don't think they're that valuable tbh. Outside of cases where you're running completely untrusted code or emulating a different architecture, there's no strong reason to pick any VM over one of the several container paradigms.

[yjftsjthsd-h]

One more usecase - which I admit is niche - is that I want a way to run multiple OSs as transparently as possible. A microvm that boots freebsd in less than a second and that acts almost like a native container would be excellent for certain development work.

Edit: Actually it's not just cross-OS work in the freebsd/linux sense; it would also be nice for doing kernel dev work. Edit my linux kernel module, compile, and then spawn a VM that boots and starts running tests in seconds.

[packetlost]

Yeah, there are definitely still cases, but they're when you specifically want/need a different kernel, which as you said are rather niche.

[mountainriver]

Oh they exist! Several of them in fact, they have never picked up a ton of steam though