[Users] Add NIC directly to VM (Dedicated)

[Shahar Havivi]

On 10.02.13 16:36, Matt . wrote:
> 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 :)
I don't remember that, sorry...
> 
> 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!
I can't reproduce this error,
its look like UI validation...
Alona,Moti did you encounter this error?

> 
> 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.
> > > >
> >