[Gllug] Xen - bit of a ramble

[Daniel P. Berrange]

On Mon, May 15, 2006 at 03:44:54PM +0100, Adrian McMenamin wrote:
> I had forgotten, of course, that Fedora installs SE Linux by default so
> when I realised that appeared to be messing up by system I removed the
> SELinux rpms whereupon I lost bash and much else besides so had to
> reinstall the whole thing.

Removing RPMs with --force will always result in much pain & suffering, the
RPM dependancies aren't just there for fun you know. SELinux can be disabled
by putting 'selinux=0' on the grub command line, or using the regular system
config files /etc/sysconfig/selinux, setting it to either 'permissive' or
'disabled'. Or there's a GUI admin tool to disable it, if you don't want to
touch the config files directly.

> Got to that point and then discovered (this is now 1am this morning) that
> the xen kernel yum offers is b0rked (see
> https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=190899) but at least
> there is a promise of a fix.

Yeah, there was a nasty mid-air collision with that kernel version which
really screwed up everything - I'm rather surprised it hasn't been pushed
from 'updates-testing' to 'update' yet considering just how broken -2111
was.

> But when I finally get that done, and get guest systems installed etc, how
> do I access the virtual systems over ssh or similar? There isn't much
> about this to be found anywhere.

THe regular Fedora Xen install script should setup a bridged network 
configuration, so your guest OS will appear to be connected directly
to the LAN in the same way a non-virtualized OS would be. So the guests
should just PXE/DHCP boot normally, be accessible via SSH just like a
physical machine would be. 

If networking isn't working for whatever reason, you can use 'xm console'
to get a serial console type connection to the guest.

> http://ftp.hpl.hp.com/techreports/2004/HPL-2004-207R1.pdf suggests using
> vnc but what about simple cli access? And how does networking work - can I
> assume that the whole xen system is a bit like a NAT-in-a-box?

No, its properly bridged to the LAN by default in Fedora, no NAT involved
anymore. 

> I know these are basic questions but I have been googling and it's not
> clear to me.

There's fedora-xen at redhat.com mailing list which may be of some use to
you. The Xen stuff is in quite a state of flux so unfortunately rather
alot of documentation on the web is misleading, just plain wrong, or
reflects a particular person's home grown solution. Hopefully things
will settle down somewhat when Xen gets merged in the upstream kernel,
only time will tell...

Regards,
Dan.
-- 
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|=-   berrange at redhat.com  -  Daniel Berrange  -  dan at berrange.com    -=|
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