Run external script when F5 change node selection with priority

File system (and remote socket) access can cause possible halts if we allowed them in the packet processing. Determining when a server goes from inactive to active is a tricky task. You could write an iRule that kept track of what servers the connections are going to and if you see a new server that's different than the previous request issue a syslog message that could trigger a trap to cause an action. Other options are to modify the URI and payload for HTTP applications to send a first command request to the new server (to an application that does your initialization and then send the original request with an HTTP::retry (in 9.2).

 

 

Another option is to use a monitoring application written with iControl running on your backend servers. If it detects that it's state is active, it can run the initialization locally.

 

 

-Joe