<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:13px">Hello,<br style="" class="">I am seeing some weird behavior in my setup and would really appreciate if someone could clarify a few things below:<br style="" class=""><br style="" class="">Setup: Simple two node. One with control+compute (Node1) and another a compute (Node2). Since, Node2 is running low in HW, I create a AvlZone putting only Node2 so that I could also launch a VM in Node2. I use OVS as mech_driver. I use type_Driver as ‘local’, for test purposes. <br style="" class=""><br style="" class="">When a VM is launched in Node2:<br style="" class=""><br style="" class="">A DHCP Discover is sent out for the veth connected to the Linux Bridge side. Eventually, both the VM and veth connected to the bridge gets IP addresses (one a .2 and another .3). Ofcourse, the external DHCP server that I use, shouldn’t have given out an IP address for the veth, which should be corrected. But, why was a DHCP sent out in the first place on behalf of the veth? I didn’t see this behavior for VM’s launched in Node1 or even in other setups (I don’t use AvlZones in other setups).<br style="" class=""><div id="yui_3_16_0_1_1433274120660_5564" dir="ltr">So, I assume Nova (or is it libvirt underneath?) creates the veth and attaches one side to br-int and another side to Linux bridge. Is it a veth or LinuxBr property that signifies this DHCP behavior?</div><br style="" class="">————————<br style="" class=""><br style="" class="">Srvr23:~$ ifconfig qvb5d8aa01c-53<br style="" class="">qvb5d8aa01c-53 Link encap:Ethernet HWaddr 62:ab:98:e4:8a:7e <br style="" class=""> inet addr:145.189.82.2 Bcast:145.189.82.255 Mask:255.255.255.0<br style="" class=""> inet6 addr: fe80::60ab:98ff:fee4:8a7e/64 Scope:Link<br style="" class=""> UP BROADCAST RUNNING PROMISC MULTICAST MTU:1500 Metric:1<br style="" class="">…………….<br style="" class=""><br style="" class="">Srvr23:~$ brctl show<br style="" class="">bridge name bridge id STP enabled interfaces<br style="" class="">qbr5d8aa01c-53 8000.62ab98e48a7e no qvb5d8aa01c-53<br style="" class=""> tap5d8aa01c-53<br style="" class=""><br style="" class="">Srvr23:~$ sudo ovs-vsctl show<br style="" class="">5dfbb68a-7d32-4efb-b9df-6e04d5c1b402<br style="" class=""> Bridge br-int<br style="" class=""> fail_mode: secure<br style="" class=""> Port int-br-ethd<br style="" class=""> Interface int-br-ethd<br style="" class=""> type: patch<br style="" class=""> options: {peer=phy-br-ethd}<br style="" class=""> Port br-int<br style="" class=""> Interface br-int<br style="" class=""> type: internal<br style="" class=""> Port "qvo5d8aa01c-53"<br style="" class=""> tag: 10<br style="" class=""> Interface "qvo5d8aa01c-53"<br style="" class=""><br style="" class="">—————————————<br style="" class=""><br style="" class="">Now, my compute server’s (Node2) default gateway is messed up and connectivity is lost. Now, the default GW points to whatever is sent out by my external DHCP server. BTW, I haven’t created any external network or Neutron routers.<br style="" class=""><br style="" class="">————<br style="" class="">Before VM was spawned:<br style="" class=""><br style="" class="">Srvr23:~$ route -n<br style="" class="">Kernel IP routing table<br style="" class="">Destination Gateway Genmask Flags Metric Ref Use Iface<br style="" class="">0.0.0.0 172.28.12.1 0.0.0.0 UG 0 0 0 eth2 <----- Original Default GW<br style="" class="">169.254.0.0 0.0.0.0 255.255.0.0 U 1000 0 0 eth2<br style="" class="">172.28.12.0 0.0.0.0 255.255.255.0 U 0 0 0 eth2<br style="" class=""><br style="" class="">After VM was spawned:<br style="" class=""><br style="" class="">Srvr23:~$ route -n<br style="" class="">Kernel IP routing table<br style="" class="">Destination Gateway Genmask Flags Metric Ref Use Iface<br style="" class="">0.0.0.0 145.189.82.1 0.0.0.0 UG 0 0 0 qvb5d8aa01c-53 <---- Default GW modified<br style="" class="">145.189.82.0 0.0.0.0 255.255.255.0 U 1 0 0 qvb5d8aa01c-53<br style="" class="">169.254.0.0 0.0.0.0 255.255.0.0 U 1000 0 0 eth2<br style="" class="">172.28.12.0 0.0.0.0 255.255.255.0 U 0 0 0 eth2<br style="" class="">------------<br style="" class=""><br style="" class=""><div id="yui_3_16_0_1_1433274120660_5595">This is stable/Juno.</div><div id="yui_3_16_0_1_1433274120660_5616"><br></div>Thanks,<br style="" class=""><div id="yui_3_16_0_1_1433274120660_5638" dir="ltr">Paddu</div></div></body></html>