Why host is not connecting to virtual servers in piranha Load balancer?

Solution Verified - Updated -

Environment

  • Red Hat Enterprise Linux 6.3

Issue

  • While testing on the piranha server everything looks to work, but when connecting to the virtual ip address form a different host there is no connection to the real server.
  • Problem running Piranha.

Resolution

  • The default gateway on the real servers should be the nat_router ip i.e. nat virtual ip.

Root Cause

  • While analysing tcpdump we found that LVS is able to forward request to the real server but Real servers are not replying back. Default gateway of all real servers was not proper.

Reference :

1) /usr/share/doc/piranha-0.8.5/docs/HOWTO.direct-routing

2) http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Load_Balancer_Administration/ch-lvs-setup-VSA.html#s1-nat-router-ifcfg-VSA

Diagnostic Steps

Example : solution would be as below:

Loadbalancer: eth0 = 172.31.91.1, eth0:10 = 172.31.91.10
Loadbalancer: eth2 = 172.31.88.9, eth2:10 = 172.31.88.10
Real Servers: 172.31.88.1, 172.31.88.2 and 172.31.88.3
  • Configure the default gateway of all real servers to use 172.31.88.10 .

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