[et-mgmt-tools] Networking modes from koan ("user" vs "bridged")
Daniel P. Berrange
berrange at redhat.com
Mon Aug 13 23:17:52 UTC 2007
On Mon, Aug 13, 2007 at 06:47:33PM -0400, Michael DeHaan wrote:
> Hi folks,
>
> Apparently I had koan set up to install Xen guests in "user" networking
> mode instead of "bridged" mode, which means the IP's the virtual guests
> would be not be accessible
> from outside the virtual host. This does not seem to be what most
> folks would want, so I've changed it to "bridged".
>
> I've fixed this upstream (see git). Basically if you want to change
> this yourself, just change "user" to "bridged" in xencreate.py
> (/usr/lib/python2.4/site-packages/koan/xencreate.py).
>
> Or, here's the patch to do the same:
>
> http://git.fedoraproject.org/?p=hosted/koan;a=commitdiff;h=3cf1bcd2a967fc8dfb84cff7b5e55234a96ed445
>
> That same one-line change is not working for me with KVM though I'm
> going to investigate and see what it takes to make KVM work this way as
> well -- assuming it's doable --
> which it most likely is.
It should work with KVM - you just need to have something to bridge to
and you need to specify what it is. There's basically 3 networking modes
- type="bridge" - bridge the virtual interface to the physical LAN. Needs
to have host setup so that one or more of the physical ethernet devices
are members of bridges. Xen's network script does this automatically for
eth0/xenbr0. I don't recommend using that though. Instead follow example
number #2 here
http://watzmann.net/blog/index.php/2007/04/27/networking_with_kvm_and_libvirt
When passing type='bridge' you also need to specufy what device you want to
bridge to - ie the name of the bridge shown by brctl show. If following the
link above, this would be 'eth0' (your physical device is peth0).
- type="network" - connect the virtual interface to a virtual network. This
virtual network consists of an isolated bridge device with no physical
devices attached. Connectivity to the outside world is via NAT. This is
xample #1 in the URL above
When passing type='user' you also need to specify what network you wanto
to attach to. Libvirt provides one called 'default' out of the box (this
is where the virbr0 comes from).
- type="user" - this is only relevant for QEMU guests - it is not supported
for Xen. It is a special NAT style connetion that doesn't rely on the
host networking stack at all. It is basically only intended for people
who don't have root who still want to use QEMU. If it works at all with
Xen that is pure luck & certainly not intended - it is a bug that libvirt
does not reject this config in the Xen case
The type='bridge' is the only one which really makes much sense for koan
I think, perhaps type='network' in some real niche cases & certainly not
type='user'.
Regards,
Dan.
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