[ovirt-users] R: R: PXE boot of a VM on vdsm don't read DHCP offer
Dan Kenigsberg
danken at redhat.com
Mon May 18 14:14:07 UTC 2015
On Fri, May 08, 2015 at 03:11:25PM +0200, NUNIN Roberto wrote:
> Hi Dan
> Thanks for answering
>
>
>
> > Which kernel does the el7 host run? I think that Ido has seen a case
> > where `brctl showmacs` was not populated with the VM mac, despite a
> > packet coming out of it.
>
> Kernel is: 3.10.0-123.20.1.el7.x86_64, package is vdsm only. Brctl isn't available within vdsm only package.
Could you try upgrading to a more up-to-date
http://mirror.centos.org/centos-7/7.1.1503/updates/x86_64/Packages/kernel-3.10.0-229.4.2.el7.x86_64.rpm
?
bridge-utils is a vdsm dependency. It must exist on your host. Please
see if the mac of the vNIC shows up on `brctl showmacs` as it should.
> >
> > Can you tcpdump and check whether the bridge propogated the DHCP offer
> > to the tap device of the said VM? Does the packet generated by
> > `ether-wake MAC-of-VM` reach the tap device?
>
> Yes: host "see" the broadcast :
> 0.000000 0.0.0.0 255.255.255.255 DHCP 346 DHCP Discover - Transaction ID 0x69267b67
> It came from the right MAC:
> Source: Qumranet_15:81:03 (00:1a:4a:15:81:03)
> And it is tagged correctly:
> 802.1Q Virtual LAN, PRI: 0, CFI: 0, ID: 3500
>
> This is the offer, on the bond interface:
> 1.012355 10.155.124.2 10.155.124.246 DHCP 346 DHCP Offer - Transaction ID 0x69267b67
> Layer 2 info:
> Ethernet II, Src: Cisco_56:83:c3 (84:78:ac:56:83:c3), Dst: Qumranet_15:81:03 (00:1a:4a:15:81:03)
> Tagging on the bond:
> 802.1Q Virtual LAN, PRI: 0, CFI: 0, ID: 3500
>
> The tag is correctly removed when DHCP offer is forwarded over the bond.3500.
> Here's the offer content, seems everything right:
>
> Client IP address: 0.0.0.0 (0.0.0.0)
> Your (client) IP address: 10.155.124.246 (10.155.124.246)
> Next server IP address: 10.155.124.223 (10.155.124.223)
> Relay agent IP address: 10.155.124.2 (10.155.124.2)
> Client MAC address: Qumranet_15:81:03 (00:1a:4a:15:81:03)
> Client hardware address padding: 00000000000000000000
> Server host name: 10.155.124.223
> Boot file name: pxelinux.0
> Magic cookie: DHCP
>
> Nothing of this offer appear on the VM side.
But does it show on the host's bridge? on the tap device?
>
> ether-wake -i bond0.3500 00:1a:4a:15:81:03 (started from the host)
> reach the VM eth0 interface:
> 2.002028 HewlettP_4a:47:b0 Qumranet_15:81:03 WOL 116 MagicPacket for Qumranet_15:81:03 (00:1a:4a:15:81:03)
>
> Really strange behavior.
>
> Roberto
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