[Gllug] Bits of virtualisation

David L Neil GLLUG at GetAroundToIt.co.uk
Thu Dec 29 09:27:02 UTC 2011


>> Should I load the 64-bit offering or in practice might the 32-bit
>> option hold advantage?
> Sort answer = 64-bit

=downloads in progress!

>> Calling for virt-expertise please.
>> I have purchased two ex-lease VT-x desktops with a view to gaining
>> some hands-on experience of KVM and maybe 'private cloud'.
>> Simultaneously I have discovered that I must install Virtual Box on
>> my Thinkpad as a prerequisite of a course commencing next month
>> (distributing envs in disk image containers?).
>> lscpu tells me the machines are all 64-bit capable and possess
>> virtualisation h/w. Thus logic directs me to install 64-bit options.
>> However might it be better to stick with the 32-bit choice in the
>> same way that historically one might do similarly to avoid browser
>> and audio-visual issues or lesser-complete software? (for example
>> GetFirefox recommends that I install the 32-bit FF on the Thinkpad's
>> Windows-as-delivered system)
>> - yes, I could make different choices in the two cases...
> I would go for 64-bit Linux for a new virtualisation host for the
> following reasons:
> 1) A 64-bit host can run 32-bit and 64-bit guests, but a 32-bit
> guest can only run 32-bit guests.

=value flexibility!

> 2) 32-bit hosts have a max guest memory limitation (2GB I think)
> 3) You can run 32-bit software on a 64-bit machine, but not the
> other way around.

=yes, what I've been doing on my Athlon dev-and-svr with 64-bit CentOS 
and 32-bit Firefox etc. Also fyi/context: previous virtualisation 
experience was on IBM mainframes.

> 4) There is no easy way to upgrade from 32-bit to 64-bit, and
> reinstalling any machine is a pain.

=I concur

> I colleague of mine runs 64-bit Ubuntu on a laptop and has not had any
> problems with Firefox. He uses libvirt with KVM (same as our servers).

=which servers are they? You run a service?

> I assume that your Windows laptop is 32-bit and will stay that way.

=apologies for mis-impression: m/c has been delivered with a 'Windows 
load' for testing/guarantee purposes. Which is as far as I have 
progressed (awaiting extra RAM that 'missed' the delivery...) It was  my 
intention to immediately load Fedora. However now that the Virtual  Box 
requirement has been reared its ugly head...

=then, no - please see below:-

> Virtual Box is a nice GUI to get a few virtual machines running on a
> desktop system, especially Windows where virtualisation options are
> more limited, but not really suitable for a server. There you'll be
> running something like KVM or Zen, with OpenStack or Eucalpytus for
> cloud management on larger clusters.

=concur again. Thus:-

Installing and learning Fedora KVM is in my plan for the two recycled 
desktop/servers/test-beds. OpenStack is what I have my eyes on for 
'cloud', but first things first (and availability of 'play time'...) 
Also invited to Red Hat's RHEV3beta but they want three dedicated 
RHEL-64 m/cs, so pulled-out.

Virtual Box is for Thinkpad and course work (but will likely suit some 
degree of client separation if I can put each one into a separate 
VM-instance...). However (from above) rather than keeping this at 
32-bits, isn't the logic to install the 64-bit Virtual Box and Fedora 
16's 64-bit desktop; and to drop down to 32-bits for the likes of 
Firefox (32-bit app on 64-bit OS/instance) only?

> I hope the course is just using Virtual Box to create disk images,
> and then distribute them to real machines.

=I don't KNOW but that's what I assume - a handy way to create a 
consistent platform amongst distributed and distant students! (also to 
keep class-work away from work-work!) I caught a brief mention in an 
overview document (eg recommended text list, etc) and nothing else is 
written down - plus everyone is 'closed for the holidays'... (see also 
(4) above!)

=Many thanks,

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