mjhjmtu

Morning all

I'm currently trying to set-up a Nested CentOS 7.0 KVM host inside a vSphere ESX 5.1.0 hypervisor. I've been following http://virtuallyhyper.com/2012/07/installing-kvm-as-a-virtual-machine-on-esxi5-with-bridged-networking/

I've managed to get the KVM Host installed successfully, and it's configured to support KVM and libvirt.

However the issue comes in when I try and pxeboot a KVM Guest against my existing DHCP server.

I can see a DHCPDISCOVER being issued by iPxe, and the DHCP server logs a DHCPOFFER, but it never receives a DHCPREQUEST from iPxe on the kvm-guest.

I've setup the KVM host with a bridged network, and disabled the 'default' NAT network:

[root@kvm-test ~]# brctl show
bridge name bridge id STP enabled interfaces
br0 8000.005056970ea0 yes ens160
 vnet0
[root@kvm-test ~]# ifconfig
br0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
 inet 192.168.18.51 netmask 255.255.255.0 broadcast 192.168.18.255
 inet6 fe80::250:56ff:fe97:ea0 prefixlen 64 scopeid 0x20<link>
 ether 00:50:56:97:0e:a0 txqueuelen 0 (Ethernet)
 RX packets 105230 bytes 13897310 (13.2 MiB)
 RX errors 0 dropped 11 overruns 0 frame 0
 TX packets 105566 bytes 44412894 (42.3 MiB)
 TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

ens160: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
 inet6 fe80::250:56ff:fe97:ea0 prefixlen 64 scopeid 0x20<link>
 ether 00:50:56:97:0e:a0 txqueuelen 1000 (Ethernet)
 RX packets 105378 bytes 15365254 (14.6 MiB)
 RX errors 0 dropped 0 overruns 0 frame 0
 TX packets 106773 bytes 44491366 (42.4 MiB)
 TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
 inet 127.0.0.1 netmask 255.0.0.0
 inet6 ::1 prefixlen 128 scopeid 0x10<host>
 loop txqueuelen 0 (Local Loopback)
 RX packets 217153 bytes 54126840 (51.6 MiB)
 RX errors 0 dropped 0 overruns 0 frame 0
 TX packets 217153 bytes 54126840 (51.6 MiB)
 TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

vnet0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
 inet6 fe80::fc54:ff:fec1:978 prefixlen 64 scopeid 0x20<link>
 ether fe:54:00:c1:09:78 txqueuelen 500 (Ethernet)
 RX packets 40 bytes 17480 (17.0 KiB)
 RX errors 0 dropped 0 overruns 0 frame 0
 TX packets 743 bytes 48921 (47.7 KiB)
 TX errors 0 dropped 755 overruns 0 carrier 0 collisions 0

The guest is configured with a 'bridged' interface:

[root@kvm-test ~]# virsh edit 2
<domain type='kvm'>
 <name>kvm-guest.test.card.co.uk</name>
 <uuid>82c15c03-aec5-4dd9-ad23-67275f742c89</uuid>
 ...
 <devices>
 <interface type='bridge'>
 <mac address='52:54:00:c1:09:78'/>
 <source bridge='br0'/>
 <model type='e1000'/>
 <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
 </interface>
 </devices>
</domain>

iptables is disabled on the KVM host, and there's no local dhcp server running.

Any ideas on what the issue could be?

Cheers

Gavin

I Had same problem and I solved it by typing the following command :

brctl setageing 'bridgename' 0. where the name of your bridge goes in the 'bridgename' spot.

To make it persitent after a reboot, you can add this command at the end of the file /etc/rc.local.

Br.

JY. A. above answer is a probable solution for your case. Setting ageing to '0' makes the Linux Bridge act as pure HUB and floods the message across all attached interfaces.

It solved my problem. I have been going through all portals and sites. Finally, the solution here worked.