Re: VMWARE/ESXi Linux

In article <slrnvkgb2b.2dr8a.mwilson@daenerys.home.mattwilson.org>,
Matthew R. Wilson <mwilson@mattwilson.org> wrote:

On 2024-11-28, Lawrence D'Oliveiro <ldo@nz.invalid> wrote:

On Wed, 27 Nov 2024 22:24 +0000 (GMT Standard Time), John Dallman wrote:
>

In article <vi84pm$6ct6$4@dont-email.me>, ldo@nz.invalid (Lawrence
D'Oliveiro) wrote:

>
On Wed, 27 Nov 2024 16:33:56 -0500, David Turner wrote:
>

I keep being told that VMWARE is not an OS in itself.
But it is... based on Ubuntu Kernel....  stripped down but still
Linux

 
And not even using the native KVM virtualization architecture that is
built into Linux.

 
History: VMware ESXi was released in 2001 and KVM was merged into the
Linux kernel in 2007.

>
In other words, VMware has long been obsoleted by better solutions.

>
Please explain how ESXi is obsolete, and how KVM is a better solution.

I wouldn't bother trying to argue with him: he's a known troll.

Both KVM and ESXi use the processor's VT-d (or AMD's equivalent, AMD-Vi)
extensions on x86 to efficiently handle instructions that require
hypervisor intervention. I'm not sure how you'd judge which one is a
better solution in that regard. So the only thing that matters, really,
is the virtualization of everything other than the processor itself.

So Goldberg defined two "types" of hypervisor in his
dissertation: Types 1 and 2.  Of course, this is an over
simplification, and those of us who work on OSes and hypervisors
understand that these distinctions are blurry and more on a
continuum than hard and fast buckets, but to a first order
approximation these categories are useful.

Roughly, a Type-1 hypervisor is one that runs on the bare metal
and only supports guests; usually some special guest is
designated as a trusted "root VM".  Xen, ESXi, and Hyper-V are
examples of Type-1 hypervisors.

Again, roughly, a Type-2 hypervisor is one that runs in the
context of an existing operating system, using its services and
implementation for some of its functionality; examples include
KVM (they _say_ it's type 1, but that's really not true) and
PA1050.  Usually with a Type-2 HV you've got a userspace program
running under the host operating system that provides control
functionality, device models, and so on.  QEMU is an example of
such a thing (sometimes, confusingly, this is called the
hypervisor while the kernel-resident component, is called the
Virtual Machine Monitor, or VMM), but other examples exist:
CrosVM, for instance.

KVM is largely dependent on qemu to provide the rest of the actual
virtual system.

I think that QEMU is what one _often_ uses, but it doesn't have
to be.  I mentioned CrosVM above, which works with KVM, but
other examplex exist: Google, Amazon, and AliBaba all use KVM on
their cloud offerings, but at least neither Google nor Amazon
use QEMU; I don't know about AliBaba but I suspect they have
their own.  (Microsoft of course uses Hyper-V.)

qemu's a great project and I run a ton of desktop VMs
with qemu+KVM, but it just doesn't have the level of maturity or
edge-case support that ESXi does. Pretty much any x86 operating system,
historical or current, _just works_ in ESXi.  With qemu+KVM, you're
going to have good success with the "big name" OSes...Windows, Linux,
the major BSDs, etc., but you're going to be fighting with quirks and
problems if you're trying, say, old OS/2 releases. That's not relevant
for most people looking for virtualization solutions, and the problems
aren't always insurmountable, but you're claiming that KVM is a "better"
solution, whereas in my experience, in reality, ESXi is the better
technology.
>
(As an aside, VMWare's _desktop_ [not server] virtualization product,
VMWare Workstation, looks like it's making moves to use KVM under the
hood, but they have said they will continue using their own proprietary
virtual devices and drivers, which is really what sets VMWare apart from
qemu. This is a move they've already made on both the Windows and Mac OS
version of VMWare Workstation if I understand correctly [utilizing
Hyper-V and Apple's Virtualization framework]. This makes sense... as I
said, the underlying virtualization of the processor is being handled by
the VT-x capabilities of the processor whether you're using VMWare,
VirtualBox, KVM, etc., so when running a desktop product under Linux,
you may as well use KVM but you still need other software to build the
rest of the virtual system and its virtual devices, so that's where
VMWare and qemu will still differentiate themselves. None of this is
relevant for ESXi, though, because as has been pointed out earlier in
the thread, it is not running on Linux at all, so VMKernel is providing
its own implementation of, essentially, what KVM provides in the Linux
kernel.)

Well, what KVM provides+a whole lot more.  ESXi is effectively
its own operating system, even though it's marketed as a type-1
HV.

qemu and KVM have the huge advantage that they are open source and free
software, of course, whereas ESXi (and vCenter) are closed source and
expensive (barring the old no-cost ESXi license).
>
But ESXi just works. It's solid, it has a huge infrastructure around it
for vSAN stuff, virtual networking management, vMotion "just works," I
find the management interface nicer than, say, Proxmox (although Proxmox
is an impressive product), etc.
>
It's sad to see Broadcom is going to do everything they can to drive
away the VMWare customer base. VMWare will lose its market-leader
position, FAR fewer people will learn about it and experiment with it
since Broadcom killed the no-cost ESXi licenses, and popularity of
Proxmox is going to skyrocket, I suspect. Which isn't a bad thing --
when open source solutions get attention and traction, they continue to
improve, and as I said earlier, Proxmox is already an impressive product
so I look forward to its future.
>
But make no mistake: VMWare was -- and I'd say still is -- the gold
standard for virtualization, both on the server (ESXi) and the
workstation (VMWare Workstation). VMWare's downfall at the hands of
Broadcom will 100% be due to Broadcom's business practices, not
technology.

Yup, it's a bit sad, though it does open up a lot of market
opportunities for other players.

I'm a bit of a free software zealot, yet even I still use ESXi for my
"real" servers. I do look forward to eventually replacing my ESXi boxes
with Proxmox for philosophical reasons, but I'm in no rush.

Check out Bhyve; it's very nice.

- Dan C.