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
I think you could help me answer the question that has been in my mind for a month :)

Is there any article that tells the difference and relationship between KVM, QEMU, libvirt, virt-manager, Xen, Proxmox etc. with their typical use cases?

>>arun-m+Le
I don't know if _one_ such article exists, but here is a piece of tech doc from oVirt (yet another tool) that shows how - or that - VDSM is used by oVirt to communicate with QEMU through libvirt: https://www.ovirt.org/develop/architecture/architecture.html...

In really simple terms, so simple that I'm not 100% sure they are correct:

* KVM is a hypervisor, or rather it lets you turn linux into a hypervisor [1], which will let you run VMs on your machine. I've heard KVM is rather hard to work with (steep learning curve). (Xen is also a hypervisor.)

* QEMU is a wrapper-of-a-sorts (a "machine emulator and virtualizer" [2]) which can be used on top of KVM (or Xen). "When used as a virtualizer, QEMU achieves near native performance by executing the guest code directly on the host CPU. QEMU supports virtualization when executing under the Xen hypervisor or using the KVM kernel module in Linux." [2]

* libvirt "is a toolkit to manage virtualization platforms" [3] and is used, e.g., by VDSM to communicate with QEMU.

* virt-manager is "a desktop user interface for managing virtual machines through libvirt" [4]. The screenshots on the project page should give an idea of what its typical use-case is - think VirtualBox and similar solutions.

* Proxmox is the above toolstack (-ish) but as one product.

---

[1] https://www.redhat.com/en/topics/virtualization/what-is-KVM

[2] https://wiki.qemu.org/Main_Page

[3] https://libvirt.org/

[4] https://virt-manager.org/

>>Izmaki+1l
Ps: typically if you want to run VMs you are faced with two paths only: 1) you want one or more VMs on your personal computer or 2) you want one or more VMs in an office environment.

On the first path you are likely going to be just fine with VirtualBox, VMWare Workstation or Hyper-V (Windows only) / Parallels (Mac intended). Which one you should pick depends on your desired use of the machines.

On the second path you would go with a solution that deals with the nitty-gritty details, such as Proxmox, oVirt, Hyper-V, ESXi, or any of the other many available options - granted you are not going full cloud-based, which opens up a whole lot of different options too.

You would generally never need to worry about which components are needed where and why. I've had to worry about it once or twice before, because I've had to debug why an oVirt solution was not behaving like I wanted it to behave. Knowing the inner workings helps in that case.