Network Dispatcher support

MQIPT can be used with IBM® Network Dispatcher to provide enhanced availability and load balancing across many servers by the use of custom advisors.

This section assumes that you are familiar with Network Dispatcher and custom advisors.

Two custom advisors are supplied with MQIPT; they can be found in the lib subdirectory. Follow the instructions in the Network Dispatcher User's Guide for installing custom advisors. Figure 1 shows an example of the use of the Network Dispatcher for monitoring port address 1414 for MQIPT. Note that each instance of MQIPT must have the same configuration file.

Follow the instructions in the Network Dispatcher User's Guide for configuring the dispatcher component to define port 1414 and the load-balanced server. We can use either the menu options of the IPT Administration Client or the ndcontrol line mode command. For example:

ndcontrol port add 10.99.1.2 : 1414
ndcontrol server add 10.99.1.2 : 1414 : 10.99.1.10
ndcontrol server add 10.99.1.2 : 1414 : 10.99.1.11
ndcontrol server add 10.99.1.2 : 1414 : 10.99.1.12

The route definition in the MQIPT configuration file would look like this:

[route]
ListenerPort=1414
Destination=10.99.1.20
DestinationPort=1414
NDAdvisor=true

We can start (and stop) a custom advisor only from the command line. For example:

ndcontrol advisor start mqipt_normal 1414

This command starts the MQIPT advisor in normal mode, in which the base advisor performs its own timings to calculate the weighting factors of each MQIPT. To use the MQIPT advisor in replace mode, add the following line to the MQIPT route definition:

NDAdvisorReplaceMode=true

You must also start the mqipt_replace custom advisor instead of mqipt_normal. For example:

ndcontrol advisor start mqipt_replace 1414

When using an advisor to monitor an SSL/TLS listener port (that is, it has SSLServer=true in the mqipt.conf configuration file), you must place a "trigger" file in the working directory of the Network Dispatcher. This "trigger" file has a specific name, relating to the route being monitored. For example, if route 1414 has SSLServer=true, a file called mqipt1414.ssl must be placed in the C:\windows\system32 directory (on Windows systems). See the mqipt1414Sample.ssl file for more information.