Re: [Xen-users] newbie in trouble with CentOS Xen

[Alexandre Kouznetsov <alk@xxxxxxxxxx>]

Hello.

Great reference.

El 05/04/13 09:28, Greg Woods escribiÃ:
> On Thu, 2013-04-04 at 16:26 -0600, Alexandre Kouznetsov wrote:
> > I expected pethX to keep the original interface's MAC.
> It doesn't on my systems. I'll admit that I do not fully understand how
> all this works, but here is partial ifconfig output from a working
> CentOS 5.9 system:
>
> eth2      Link encap:Ethernet  HWaddr 00:1B:21:A1:CA:B0
>            inet addr:192.168.203.2  Bcast:192.168.203.255
> Mask:255.255.255.0
>            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>            RX packets:40680 errors:0 dropped:0 overruns:0 frame:0
>            TX packets:40048 errors:0 dropped:0 overruns:0 carrier:0
>            collisions:0 txqueuelen:0
>            RX bytes:10464680 (9.9 MiB)  TX bytes:10335739 (9.8 MiB)
>
> peth2     Link encap:Ethernet  HWaddr FE:FF:FF:FF:FF:FF
>            UP BROADCAST RUNNING NOARP  MTU:1500  Metric:1
>            RX packets:40298 errors:0 dropped:0 overruns:0 frame:0
>            TX packets:40189 errors:0 dropped:0 overruns:0 carrier:0
>            collisions:0 txqueuelen:1000
>            RX bytes:9853371 (9.3 MiB)  TX bytes:10403372 (9.9 MiB)
>            Memory:fa7e0000-fa800000
>
> xenbr2    Link encap:Ethernet  HWaddr FE:FF:FF:FF:FF:FF
>            UP BROADCAST RUNNING NOARP  MTU:1500  Metric:1
>            RX packets:78922 errors:0 dropped:0 overruns:0 frame:0
>            TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
>            collisions:0 txqueuelen:0
>            RX bytes:19374293 (18.4 MiB)  TX bytes:0 (0.0 b)
>
>  From "brctl show":
>
> xenbr2          8000.feffffffffff       no              vif5.1
>                                                          vif4.1
>                                                          vif3.1
>                                                          vif2.1
>                                                          vif1.1
>                                                          vif0.2
>                                                          peth2
>
> Then all the /etc/xen config files just reference xenbr2.
> All of the xenbrX and pethX devices have this same pseudo-MAC address.
> It is not clear to me how they are connected to the underlying ethX
> device.
It seems like, Dom0's IP connectivity is not done directly via the 
actual device. Instead it creates a vif0.2 and maps it as eth2 to Dom0, 
as it would do with any other Dom.
Seems much cleaner than the setup I described before, as "old ways", 
when a eth was renamed to peth and a bridge called eth was created.
> All this said, if "ifconfig eth0" shows no output, while this device is
> supposed to be used for bridged networking in Xen, that's a problem. If
> it were me, I'd be looking at "dmesg" output to figure out why the
> "eth0" device isn't being set up at boot time. Fix what you know is
> broken first.
I's more clear to me now.
In Dave's case, "ifconfig eth0" within Dom0 should show a eth0 in 
inactive state. That should be normal, if Dom0 where not supposed to 
have a IP interface for that network.
What is still weired, is that he said his eth1 goes to a Cisco router, 
while this configuration would make more sense if eth0 where the public 
interface.
Hey, Dave, didn't you misswired your Supermicro networking connections?


--
Alexandre Kouznetsov


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