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

[Rik Theys]

Hi,

Is your DHCP server a VM running on the same host? I've seem some
strange issues where a VM could not obtain a DHCP lease if it was
running on the same physical machine as the client. If this is the case,
I can look up what I had to change, otherwise ignore it.

Regards,

Rik

> Further info about this case:
> 
> An already installed and running VM (Centos7) with static IPv4 assignment, if  changed to DHCP mode, do not acquire the
> IP address.
> 
>  
> 
> In this case, tcpdump taken on the VM, do not show DHCP offer packets that are instead seen on the host bond interface.
> 
> Seems that something is filtering DHCP offers between host physical eth interfaces and VM virtio eth interface.
> 
> Physical servers on the same VLAN keep DHCP offers and boot from PXE correctly.
> 
>  
> 
> Roberto
> 
>  
> 
>  
> 
>  
> 
> >Hi all
> 
>  
> 
> >We are using oVirt engine 3.5.1-0.0 on Centos 6.6
> 
> >We are deploying two hosts with vdsm-4.16.10-8.gitc937927.el7.x86_64
> 
> >No hosted-engine, it run on a dedicates VM, outside oVirt.
> 
>  
> 
> >Behavior: PXE boot of a VM, ends in timeout (0x4c106035), instead to accept the DHCP offer coming from DHCP server.
> 
> >Tcpdump capture started on the vdsm host, bond0 interface shows clearly that DHCP offers reach the vdsm interfaces
> >three times before PXE client ends in timeout.
> 
> >Incoming DHCP offer is correctly tagged when it comes to the bond0 interface and forwarded to the bond0.bridge
> >interface.
> 
> >PXE simply ignore it. PXE version is gPXE 0.9.7.
> 
> >bond0.bridge interface is already setup with STP=off and DELAY=0.
> 
>  
> 
> >If we install a VM using command  line boot parameters, VM install & run fine. The issue is only related to PXE
> process, >when it is expected to use the DHCP offer.
> 
>  
> 
> >I can provide tcpdump capture, but I’ve not attached to the email because I’m quite new of the community and don’t
> >know if it is allowed/correct.
> 
>  
> 
> >On another host, under the same engine, running vdsm-4.16.12-7.gita30da75.el6.x86_64 on Centos6.6, this behavior is
> >not happening, everything works fine.
> 
>  
> 
> >Any idea/suggestion/further investigation ?
> 
> >Thanks for attention
> 
> >Best regards
> 
>  
> 
>  
> 
> Roberto Nunin
> 
> Infrastructure Manager
> 
> Italy
> 
>  
> 
>  
> 
> Here are interfaces configs:
> 
> eno1:
> 
> DEVICE="eno1"
> 
> HWADDR="38:63:bb:4a:47:b0"
> 
> MASTER="bond0"
> 
> NM_CONTROLLED="no"
> 
> ONBOOT="yes"
> 
> SLAVE="yes"
> 
> eno2:
> 
> DEVICE="eno2"
> 
> HWADDR="38:63:bb:4a:47:b4"
> 
> MASTER="bond0"
> 
> NM_CONTROLLED="no"
> 
> ONBOOT="yes"
> 
> SLAVE="yes"
> 
> bond0:
> 
> BONDING_OPTS="mode=4 miimon=100"
> 
> DEVICE="bond0"
> 
> NM_CONTROLLED="no"
> 
> ONBOOT="yes"
> 
> TYPE="Bond"
> 
> bond0.3500:
> 
> DEVICE=bond0.3500
> 
> VLAN=yes
> 
> BRIDGE=DMZ3_DEV
> 
> ONBOOT=no
> 
> MTU=1500
> 
> NM_CONTROLLED=no
> 
> HOTPLUG=no
> 
> DMZ3_DEV:
> 
> DEVICE=DMZ3_DEV
> 
> TYPE=Bridge
> 
> DELAY=0
> 
> STP=off
> 
> ONBOOT=no
> 
> MTU=1500
> 
> DEFROUTE=no
> 
> NM_CONTROLLED=no
> 
> HOTPLUG=no
> 
>  
> 
>  
> 
>  
> 
> 
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