Re: [ovirt-users] R: PXE boot of a VM on vdsm don't read DHCP offer
On Thu, May 07, 2015 at 06:01:14PM +0200, NUNIN Roberto wrote:
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
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.
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?
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