[Users] Add NIC directly to VM (Dedicated)

[Matt .]

Hi,

I'm thinking about the way how I did that with the dedicated NIC to the VM.
I was discussing this a couple of months ago on IRC but I can't remeber and
I already tried to do this... no luck yet. I remember that the NICS were
just available when adding a nic to the VM, by MAC-address. Can't figure it
out yet what I did those except of not sleeping that much :)

About the error that I get I do the following:


Hosts > Network Interfaces > Setup Host Networks.

When I drag a network I created to a NIC and I don't set an IP or DHCP or
None I get that error: "Error while executing action Setup Networks:
Illegal or Incomplete IP Address"

When I set and IP to that network that is draaged to the Nic I don't get an
error, but why only and IP and no GW as this is IP seems to be bridged in
the host to the VM where you add a Nic to with that same network you just
gave an IP.

When saying the above, could have been possible that I have set the
Mac-Address of the real Nic @ the VM Nic ? As this is possible that might
have been the solution I used ?

For the rest this software is good and the support is superb!

Thanks so far again.

Matt


2013/2/10 Shahar Havivi <shaharh at redhat.com>

> On 10.02.13 16:16, Matt . wrote:
> > Hi Shahar,
> >
> > Thanks, I need to work this out further to have it 100% visible.
> >
> > I wonder why I was able in the past (3.1) to dedicate an NIC to a VM.
> >
> > Do you also have an explanation why I cannot save a network configuration
> > with a nic in DHCP mode ? It complains about a wrong IP and I have seen
> it
> > should be a bug. Is this right ?
> How did you that...
> I.e can you tell me the steps that you made in the UI? (for both cases)
> >
> > Cheers,
> >
> > Matt
> >
> >
> > 2013/2/10 Shahar Havivi <shaharh at redhat.com>
> >
> > > On 10.02.13 14:13, Dan Kenigsberg wrote:
> > > > On Sun, Feb 10, 2013 at 12:19:57PM +0100, Matt . wrote:
> > > > > Hi,
> > > > >
> > > > > For setting up a firewall in a VM I would like to add 2 of my 4
> nics
> > > > > directly to a VM.
> > > > >
> > > > > In my previous setup I thought I have done that, but at the moment
> I
> > > cannot
> > > > > figure this out and cannot find the docs to accomplish this.
> > > > >
> > > > > I would like to dedicate those 2 nics to my firewall VM's to avoid
> > > sharing
> > > > > them using a network per accident to other VM's.
> > > > >
> > > > > How is this be done at the moment ?
> > > >
> > > > AFAIK it can be done only with a vdsm hook. You'd need to define
> your VM
> > > > with no interface at all, but instead, mark it with a special custom
> > > > property you define. Then, you should write a hook that adds the two
> > > > host interfaces to the VM, by means of either
> > > > http://libvirt.org/formatdomain.html#elementsNICSDirect or
> > > > http://libvirt.org/formatdomain.html#elementsNICSHostdev
> > > >
> > > > Most probably, you would need to pin your firewall VM to a specific
> > > > host.
> > > >
> > > > Writing a hook is not too complex, but it requires understanding of
> how
> > > > vdsm and libvirt works. You can take
> > > > http://gerrit.ovirt.org/gitweb?p=vdsm.git;a=tree;f=vdsm_hooks/vmfexas a
> > > > reference, or ask for specific guidance here.
> > > >
> > > > Dan.
> > > Dan is right,
> > > Currently you can do it via hook,
> > > We do have promisc mode but currently we have mirroring mode only (ie
> you
> > > can
> > > monitor each VM traffic but cannot intercept it).
> > > The way to do it is via layer 2.
> > >
> > > its best to implement after_vm_start hook and use ebtables.
> > > you can pass to the hook the network name.
> > > when you have the network name you can prob for its mac address and in
> the
> > > libvirt xml
> > > you can view the interfaces that are part of that network and get the
> mac
> > > addresses as well. (look at other hooks as Dan point out)
> > >
> > > when you have the network name the network mac and the target
> interface you
> > > can use ebtables:
> > > 1. set the bridge in promisc mode
> > >    $ ifconfig <netwok name> promisc
> > > 2. traffic to the monitoring machine
> > >    $ ebtables -t nat -A PREROUTING -d 00:1a:4a:16:01:51 -i eth0 -j dnat
> > > --to-destination 00:1a:4a:16:01:11
> > > 3. traffic from the monitoring machine
> > >    $ ebtables -t nat -A PREROUTING -s 00:1a:4a:16:01:51 -i vnet0 -j
> dnat
> > > --to-destination 00:1a:4a:16:01:11
> > >
> > > 1. set the network interface in promiscous mode
> > > 2. traffic that ment to the vm mac will go to the destination mac
> > > 2. traffic that sent from the vm mac will go to the destination mac
> > >
> > > note that the -i <interface> is the interface name and I think it can
> be
> > > omitted...
> > >
> > > Shahar Havivi.
> > >
>
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