[wellylug] Server virtualisation

Daniel Pittman daniel at rimspace.net
Fri Nov 28 14:01:34 NZDT 2008

"Callum Grant" <callum.el.grant at gmail.com> writes:

> I've recently come to the conclusion that since I need to run many
> different linux operating systems at once, I need to build a beefy
> virtualisation machine.

You really shouldn't need that for your use case, which you later
clarified is essentially "create a throw-away slice of a machine, plus a
couple of persistent slices".

> Can anyone recommend an open source virtual machine tool that I could
> use( not something like virtualbox though, e.g. geared to having at
> least 3 machines going at once).

Well, the other suggestions in the thread have been good, but two have
been missed:

KVM, which depends on having a processor with hardware support for
virtualization, works well and is now the "official" option for Fedora,
RHEL and Ubuntu, and is will supported in Debian.

If I had to use a "pretend hardware" solution that is what I would

For your use case, though, having to dedicate memory to each instance
and deal with multiple schedulers, etc, seems a significant waste of

I use, and would recommend to you, the OpenVZ solution.  This is a
"containers" solution, where a single kernel is used, but multiple
separate namespaces exist for resources such as the network, process and
user accounting.

This has a vastly lower overhead than pretend hardware, doesn't steal
and retain a chunk of memory for each container, and works very smoothly
in terms of scheduling overheads, etc.

For ease of use a CentOS 5 system with their YUM repository is probably
the best choice — this mirrors the upstream developers core platform, as
well as the supported platform for the commercial Virtuozzo variant.

I use it on Ubuntu 8.04, though, and Debian also ship with good OpenVZ
support, so I could happily recommend either of those as a platform.

Anyway, I generally recommend OpenVZ rather than a paravirtualized or
pretend hardware solution for "multiple linux distributions /
instances", and have used it with great success commercially.


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