[ovirt-users] R: R: PXE boot of a VM on vdsm don't read DHCP offer

NUNIN Roberto Roberto.Nunin at comifar.it
Fri May 8 13:11:25 UTC 2015


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.
>
> 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.

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


Questo messaggio e' indirizzato esclusivamente al destinatario indicato e potrebbe contenere informazioni confidenziali, riservate o proprietarie. Qualora la presente venisse ricevuta per errore, si prega di segnalarlo immediatamente al mittente, cancellando l'originale e ogni sua copia e distruggendo eventuali copie cartacee. Ogni altro uso e' strettamente proibito e potrebbe essere fonte di violazione di legge.

This message is for the designated recipient only and may contain privileged, proprietary, or otherwise private information. If you have received it in error, please notify the sender immediately, deleting the original and all copies and destroying any hard copies. Any other use is strictly prohibited and may be unlawful.



More information about the Users mailing list