Clone, what does it do technically in an iRule?

Ok, first of all, thank you Steve and Aaron. I didn't use SNMP/SMTP or HSL but our conversation made me realize a simpler solution that fits within my realm of control. My LTM's are not running in appliance mode so theoretically I could have created a custom SNMP trap and used SMTP out -- but I do not have command line access to our devices and my familiarity with Linux is limited to the fact that I know he always has his blanket with him. I also had read that piece about using HSL for request cloning several times but was scared off from it every time by the use at your own risk language and some events I don't normally use.

 

 

I finally realized through our conversation that what I wanted was an extra http_request to go and do some work for me when a node in my pool was down and since my work server was a regular web/app setup that clone was not going to do it because of tcp stack/ip binding on the web server. So I created an *extra* request in my shared application header that gets included in all my applications. Along with other secondary in-line requests for jQuery, fancybox, css and all the stuff I include I added another in-line link for F5_Node_Alert.js to do my work. The node alert javascript file only contains a comment about it's purpose and is only about 40 bytes. When the client browser receives a page from the primary request that includes the common header, it then spawns additional secondary requests back to the F5 for all the necessary resources. Only if my app pool is less than it's max members then I check the uri of the dozen or so additional requests. When I find the *extra* request for the node alert file I send it over to the node down pool which decodes the domain and notifies everyone via email and sms that a node is down. If all the members are up, it just includes the little 40 byte comment file. If all the members are down, it sends the primary http request to the pool down pool which notifies everyone the whole pool is down.