open-source virtualization software...and moving off-topic

Kent Borg kentborg at borg.org
Fri Dec 14 18:18:38 EST 2007


Eugene Gorelik wrote:
> I am considering different virtualization software to create isolated
> environment for Development and QA and let developers shell access to the
> virtual environments.
> I am comparing Xen and OpenVZ. They provide different level of
> virtualization and OpenVZ is like an advanced jail, but I really like it
> because it has minimal performance overhead comparing to Xen. 

Xen is brittle.  Choose something where the client is more independent 
of the host.  A host upgrade in Xen can easily break your existing 
clients because both the host and client have to run matched kernels.  
The fact that Openvz is Linux-only makes me worry it might also have a 
too-tight coupling between host and guest.

Being completely virtual is a real nice feature.  It lets you run old or 
obscure stuff without any pesky version-skew issues. 

If I had KVM-compatible hardware I would run it, as it is I don't, so I 
chose what I think is the next closest thing: straight Qemu.


Somewhat off topic...

The popularity of virtualization brings up an interesting point.  To me 
it indicates a failure of Linux, et al. 

Linux offers some very cool features and APIs, yet the really *hot* API 
in the year 2007 is...<drum roll please>...a slightly evolved, bastard 
version of the original BIOS-architecture IBM hastily put in their 
original PC.  This is a design from over a quarter century ago, it was 
made for an 8-bit CPU, that ran at under 5 MHz, and could not have an 
entire megabyte of RAM.  I do note, however, that, as old as the PC is, 
the fundamental design of Unix (which Linux largely copies), is even older.

Unix/Linux is a multiuser design, the users are protected from each 
other.  So why isn't it good enough?  What is lacking from the services 
offered by the OS that so many of us are drooling over a simulated raw 
IBM PC?  What is so wrong with the OS that, as bloated as the OS can be, 
we are wanting to run multiple copies on a single computer?

I think the assumed requirements of what an OS does is in need of change.

Note that using virtualization as a way to host old software *is* pretty 
compelling, but people doing new engineering are using virtualization in 
their *NEW* designs!  Something is rotten in the state of our OS 
assumptions.


-kb, the Kent who frequently laments the lack of innovation in the 
tradition-bound computer world.


P.S.  It is almost as if shared libraries were the big mistake, that the 
savings came at such a high price in version hell, that we are willing 
to duplicate the whole OS to dig ourselves out.  This is clearly not the 
entire story, but it is part of it.

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