[Openstack] packets not reaching VM

Priyanka ppnaik at cse.iitb.ac.in
Wed Jun 22 07:42:07 UTC 2016


Hi,

We have a Openstack Juno setup with 1 controller+neutron node and 3 
compute nodes. 1 VM (LB) has ipvsadm installed and two VMs act as back 
end server.

On the server with ipvsadm I have eth0:0 IP as 192.168.1.21 which acts 
as application IP. The ipvsadm uses round robin scheme. This is done 
using commands as below:

sudo ipvsadm -A -t 192.168.1.21:6000 -s rr
sudo ipvsadm -a -t 192.168.1.21:6000 -r 192.168.1.77:6000 -g
sudo ipvsadm -a -t 192.168.1.21:6000 -r 192.168.1.79:6000 -g

where 192.168.1.77 and 192.168.1.79 are back end server VM IP.

The problem is that the packets go out of the LB VM but never reach the 
back end server.

In the tcpdumps on various interfaces show that the packet reach till 
qbr of the LB VM but donot reach the qvo interface of LB VM. Are there 
any rules that get applied here which block these packets. The packets 
from the client VM are sent to back end server by the LB VM by changing 
the destination MAC of the packets.
  The packets that leave LB VM to reach back end VM have source as the 
client VM IP and destination IP as 192.168.1.21 (application IP) and the 
src MAC of LB VM and dst MAC of backend server VM. Is this the reason 
for the packets to be blocked. Is there any way to allow these packets 
to flow to the back end server?

Please help us regarding this.


Thanks,

Priyanka






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