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Comment by xmichael999 | Hacker News Reader

Does anyone actually use Xen as a VM host anymore? I thought it was pretty much dead?

Bit of a surprising comment - Xen is very widely used - even all of AWS is Xen (I believe), are you perhaps thinking of XenServer (Citrix's OS / Distro based on Xen)?

If you do mean XenServer, well - yes some large places are still using it but it's definitely dying out after they proved very slow to deliver new features then put a restriction on free / open source users as of 7.3 onwards that prevents clusters great that 3 hosts rendering mostly useless.

XCP-ng (https://xcp-ng.org/) is a fork of XenServer which is picked up where XenServer left off and is doing a lot in a short period of time (IMO) to add new features and build / support the community.

> even all of AWS is Xen

Majority, but the latest generation ("nitro") uses KVM.

AWS has been maintaining there own custom version for more than 2 years based on the open source code, and mostly use KVM now from what I understand.

I'm curious what led you to believe Xen was dead...?

There have been notable departures from Xen to KVM in the hosting space. Linode, for example. And while I did note in another comment that AWS uses Xen, it is also migrating away to KVM. Their firecracker VM is also KVM based. It seems fair to characterize it as legacy...though perhaps not dead.

The company I work for produces a VM based product and distributes at least 100 instances (copies of the VM product) a month. We ask what VM platform (and have maintained Xen support) in more than a year not one person has bought a Xen instance. Tons and tons of Hyper-V a fair bit of Vmware and a boat load of KVM variations (Generally using Proxmox and VirtualBox, or a taste of doing it ourselves) but never Citrix. I believe of the 3000+ instances we support only about 100 are Xen based.

Big and little providers are still using it. AWS and Prgmr.com, for example.

AWS is beginning to migrate away from it towards their in-house stuff, though.

(And though you're correct with regards to the question, I don't believe AWS uses Citrix's XenServer.)

Isn’t most of the legacy AWS EC2 stuff Xen?

Is the Xen VM host distinct from Xen the hypervisor? I'm pretty sure QubesOS still uses Xen for that.

No, Xen and XenServer are distinct because of that. The host OS can in theory be any OS (but almost always GNU/Linux). Xen is a type 1 hypervisor running before the OS kernel is even loaded.

Everyone not using KVM is using Xen, for local installs that is. There are other products but none of them are open enough to be considered in those cases.

That's probably broadly true, but on the low-end there are a lot of shared-hosting companies who use nothing, and a bunch of people sharing resources via OpenVZ etc.

Hence the 'for local installs that is' ;-)

There are generally two big FOSS hypervisors (Xen, KVM), a bunch of smaller ones (bhyve, vmm, the one in l4) and the somewhat-open ones like VirtualBox-OSS.

Then again, the whole local setup scope is a niche in itself.

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