For more information regarding the security incident at F5, the actions we are taking to address it, and our ongoing efforts to protect our customers, click here.

Forum Discussion

Brady_11518's avatar
Brady_11518
Icon for Nimbostratus rankNimbostratus
Apr 26, 2013

Check if node is offline (down) or unavailable (busy)

I'd like to be able to return two different splash pages if there is a problem, one if the nodes are all offline due to monitor failure (site down for maintenance), but a different one if no nodes ar...
application delivery
dev
devops
iRules
Kevin_Stewart's avatar
Kevin_Stewart
Icon for Employee rankEmployee
Apr 29, 2013
Aside from writing you're own connection limiting code, it would be difficult, in an iRule, to differentiate between an "up" server and an unavailable server (which is also technically "up"). You can, however, differentiate between a "down" server (based on a monitor) and a server that is administratively taken offline. As for the unavailable servers, you should be able to alleviate this with TCP queuing, so that when a server reaches its connection limit, requests are queued until either the resource frees up or some threshold it met.

 

 

TCP queuing was introduced in 11.0.0, so if you have the "Enable Request Queuing" option in the pool member configuration settings, you can enable this and control the actual queuing with an iRule. See the following wiki page for more information:

 

 

https://devcentral.f5.com/wiki/iRules.LB_queue.ashx