zlacker

>>hugodu+(OP)
Listen people, Firecracker is NOT A HYPERVISOR. A hypervisor runs right on the hardware. KVM is a hypervisor. Firecracker is a process that controls KVM. If you want to call firecracker (and QEMU, when used in conjunction with KVM) a VMM ("virtual machine monitor") I won't complain. But please please please, we need a word for what KVM and Xen are, and "hypervisor" is the best fit. Stop using that word for a user-level process like Firecracker.

>>gwd+j3
> virtual machine monitor

Is it good to think of libvirt as a virtual machine mointor, or is that more "virtual machine management"?

>>Muffin+Qc
I'd love to get a clear explanation of what libvirt actually does. As far as I can tell it's a qemu argument assembler and launcher. For my own use-case, I just launch qemu from systemd unit files:

https://wiki.archlinux.org/title/QEMU#With_systemd_service

>>zbroze+Yf
> As far as I can tell it's a qemu argument assembler

Raises a few questions to me:

Can you use KVM/do KVM stuff without QEMU?

Can you do libvirt stuff without QEMU?

Hoping the answers to both aren't useless/"technically, but why would you want to?"

>>Muffin+Ol
> Can you use KVM/do KVM stuff without QEMU?

Yes there's a few things out there like Firecracker that use KVM without using QEMU. I'm not completely aware of all of them but they do exist

> Can you do libvirt stuff without QEMU?

Yes it can also manager LXC containers and a few other types like Xen and Bhyve and Virtuozzo, like QEMU without KVM. The without KVM part is important to letting you run VMs that are emulating other architectures than the native one.

For a good bit of this, it is "why would you want to" but there are definitely real cases where you'd want to be able to do this. Like the LXC or Virtuozzo support means that you can run lighter weight containers (same underlying tech as Docker essentially) through the same orchestration/management that you use for virtual machines. And the Bhyve support lets you do the same thing for running things on top of FreeBSD (though I've never used it this way) so that a heterogeneous mix of hosts is managed through the same interfaces.