Direct Server Return Example with Two Single Legged Nodes and VRRP-HA

Figure 1: Network Setup

This example is similar to example 3, but shows the following more advanced techniques:

• Dual node HA setup with session table synchronization,
• Dual port setup which associates ports 80 and 443 to the same session,
• Health check with external http.monitor script,
• Session creation based on system load feedback retrieved with the BalanceNG agent "bngagent".

Establishing the Loopback Aliases

Use the following commands to establish the Loopback-alias on the Targets (as in example 3):

Linux:
  ifconfig lo:0 <IP-address> netmask 255.255.255.255 -arp up
Solaris:
  ifconfig lo0:1 plumb
  ifconfig lo0:1 <IP-address> netmask 255.255.255.255 up

In our example this would be the following command line (assuming a Linux operating system) executed on both Target 1 and Target 2:

# ifconfig lo:0 172.16.1.10 netmask 255.255.255.255 -arp up

Additionally it is necessary to disable invalid ARP replies (Linux 2.6 kernel, take a look at the FAQ question Q2.09):

# echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore
# echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce

If the target is a Windows system, please follow the steps in the FAQ question Q2.14.

Starting "bngagent" on both targets

The BalanceNG feedback agent has to be started on reboot on both targets listening on port 439 like this:

# /usr/local/bin/bngagent 439

The Master and Backup configuration files

The default parameter settings of "vrrppreempt" and "sessionssync" are unchanged in order to enable session table synchronization together with a master priority not equal to 255.

The server definition contains two ports 80 and 443, which declares connections to either of them to be related to the same session. If two ports are specified in a server, the target definitions of the associated targets must not contain any specific port or protocol settings.

• Example 5 Master Configuration File
• Example 5 Backup Configuration File

Please contact us in case of further questions, errors or suggestions at info@inlab.de.