Re: Guests networking using driver domain

[Andrea Stevanato <andrea.stevanato@xxxxxxxxxxxxxxx>]

Hi,

On 03/03/2022 19:18, tosher 1 wrote:
> Hi Andrea,
>
> Can you access the network from the driver domain? I guess not because I see 
> you are not using a PCI passthrough network device in the driver domain. You 
> are not even using a virtual network in the driver domain. Therefore, even if 
> you can connect the guest domain (guest1) with the diver domain, you will not 
> have access to the network to talk to the outside world.
Well that is actually what I'm trying to achieve, the guests have just 
to be able to communicate with each other.
> I was able to make the driver domain work using the Ethernet PCI passthrough. 
> Detail on PCI passthrough can be found in the following link.
>
> https://wiki.xenproject.org/wiki/Xen_PCI_Passthrough
>
> I was not able to make the driver domain work having the virtual network in the 
> driver domain (guest0). It creates a nested paravirtualized network, which is a 
> little complicated. But, there should be some way to make it work.
>
> On top of that, to make a domain work as driver domain, you need to run the 
> following command to launch the driver domain daemon (guest0) before you launch 
> the guest domain (guest1).
>
> #xl devd
>
> If you do not have access to this daemon, we need to install it first in the 
> driver domain (guest0). One way to install this is to install Xen hypervisor on 
> the driver domain, but skip booting the Xen by selecting other option, say 
> Ubuntu, from the boot menu.
Btw it finds out that there is a BUG, 
https://lists.xenproject.org/archives/html/xen-devel/2022-03/msg00279.html
> I hope this helps.
>
> Bests,
> Mehrab
>   
>
>
>
> On Thursday, March 3, 2022, 07:30:05 AM EST, WebDawg <webdawg@xxxxxxxxx> wrote:
>
>
>
>
>
> Have you check that the interface is up on guest1?
>
> What I mean is have you configured the interface inside of guest1? ifconfig/ip
>
> On Thu, Mar 3, 2022, 5:32 AM Andrea Stevanato 
> <Andrea.Stevanato@xxxxxxxxxxxxxxx> wrote:
> >    
> >    
> >    
> >    
> > Hi all,
> > I'm trying to configure two guests that can communicate with each other using a 
> > "virtual" network card exploiting the netback and netfront driver.
> >
> > The first guest is created with the following configuration:
> >
> > name    = "guest0"
> > kernel  = "/media/sd-mmcblk0p1/Image"
> > ramdisk = "/media/sd-mmcblk0p1/rootfs.cpio.gz"
> > extra   = "console=hvc0 rdinit=/sbin/init root=/dev/ram0"
> > memory  = 1024
> > vcpus   = 2
> >
> > Once it is up and running, I create and setup the bridge:
> >
> > # brctl addbr xenbr0
> > # ip addr add 10.0.3.1/24 dev xenbr0
> > # ip link set dev xenbr0 up
> >
> > Then I configure the udhcpd server with the following configuration 
> > (/etc/udhcpd.conf):
> >
> > start 10.0.3.15
> > end 10.0.3.254
> > interface xenbr0
> > option subnet 255.255.255.0
> >
> > And start it with: `# udhcpd`​.
> >
> > The second guest is created with the following configuration:
> >
> > name    = "guest1"
> > kernel  = "/media/sd-mmcblk0p1/Image"
> > ramdisk = "/media/sd-mmcblk0p1/rootfs.cpio.gz"
> > extra   = "console=hvc0 rdinit=/sbin/init root=/dev/ram0"
> > memory  = 1024
> > vcpus   = 2
> > vif = [ 'bridge=xenbr0, backend=guest0' ]
> >
> > Once it is up and running on the guest0 the new interface (vifX.0) is created 
> > correctly, however on the guest1 the eth0 interface is not present.
> >
> > If I do the exact same thing on dom0, instead of guest0 (without attaching the 
> > eth0 to the bridge, since I do not need to reach outside), the eth0 on the 
> > guest is created correctly and get the 10.0.3.15 IP address.
> >
> > What I'm doing wrong?
> >
> > Andrea
Andrea