[linux-elitists] Virtualization

J. Paul Reed preed@sigkill.com
Wed Feb 23 13:53:27 PST 2005

On 23 Feb 2005 at 09:00:38, Greg KH arranged the bits on my disk to say:

> > Ahh... and Xen is different how? Oh right... they just modify the whole
> > damn kernel (and require you to patch your entire kernel every rev).
> No, Xen is going to make it into the mainline kernel soon, and then no
> patching will be needed.  When will vmware achieve this goal?  :)

Everyone is saying "Xen is going to be in the mainline kernel; no, really!"

I'm not disputing this fact, but I'll believe it when I see it. Right now,
it's vaporware. And a really crappy argument.

> No, I complain as the vmware module taints my kenel, requires a separate
> step to build from my normal kernel build process, and if I load it into
> my kernel, I invalidate any and all support contracts I might have paid
> for, and I can no longer ask for help with any kernel problems from
> anyone in the open source kernel community.

Some people actually want to use their Linux box to do useful things. If
you want to have the "purity" argument, go troll some Debian lists.

Me, I have no problem with a module that taints my kernel, especially when
I have source for it.

And with any other product, you can get support from VMware; they did,
after all, write it, and support is available. It's pretty good, to hear
other people talk about it, too.

> I also complain that the module is fragile in that sometimes it doesn't
> build properly due to the kernel apis changing all the time (and yes,
> that's sometimes due to work that I do, see
> http://www.kroah.com/log/linux/stable_api_nonsense.html for details as
> to why this will not change.)

Like all software, there are distributions and kernels which are supported
and those which are not.

I don't see you complaining that NPTL doesn't run on the 1.2.x kernel

You're effectively complaining about a subjective values judgement ("This
commercial software restricts me from what I can tinker with somewhat.") We
have different values, and neither is objectively "better" than the other,
although as I point out below, some of your complaints are invalid, due to
invalid information.

> > The correct answer is ESX is its own, proprietary kernel that was
> > developed entirely in house, and has nothing to do with a 2.4.9 kernel.
> Then why is a hacked up 2.4.9 kernel included in the ESX product?  See
> http://vmware-svca.www.conxion.com/secured/esx/VMware-esx-public-source-2.5.0-11343.tar.gz
> for details.
> Is this kernel the guest os?  And if so, why can't someone use any
> kernel they want as the guest os?  Or is it the host os as vmware is
> taking advantage of Linux drivers?

It's the Service Console.


It is not used for any of the things you mention.

In some sense, it's a glorified boot loader.

> Anyway, I'm not trying to argue here.  vmware is a great product, I use
> it all the time to reverse engineer windows drivers :)

That's a common use.

> I just don't like the fact that their kernel modules are not included in
> the main kernel tree.  I view Linux closed source modules as derivative
> works, and feel they should be required to be released under the GPL.  I
> know a lot of IP lawyers who also feel the same way.  See my, and other
> kernel developers effort to help fix this issue in the recent kernel
> releases (marking non-needed functions static, use of EXPORT_SYMBOL_GPL,
> etc.)

Except uhh... they're not closed source. You're whining about the binary
pre-built modules.

Don't want to use them? Compile your own modules; you have to do that
anyway if you're running a kernel version that doesn't have binary
pre-built modules. (And since you have to compile them yourself... uhh...
there's source code there.)

So I really don't know what you're whining about.

> I also begrudge the fact that the amount of development effort that
> vmware gives back to the kernel community is pretty much non-existant,
> in comparison to everything they are taking from it.  But for more
> details on that topic, see my OLS paper for this year...

What else would you like them to do?

They a) obviously don't take as much as you think they do; you're clearly
just plain wrong about what their "bread and butter" product actually is,
so they're not "stealing" what you think they are and b) they release all
of the changes they make to GPL software (see the tarball you link to
above), exactly as the GPL requires.

They also happen to support open source projects like Mozilla and Samba.

So... why exactly are you complaining again?

J. Paul Reed -- 0xDF8708F8 || preed@sigkill.com || web.sigkill.com/preed
Math, my dear boy, is nothing more than the lesbian sister of biology.
                                            -- Peter Griffin, Family Guy

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