Triggering a holding page for all virtual servers

Hi Dave,

In order to have an iRule take effect on all virtual servers, the iRule would need to be applied to all virtual servers. I think your initial thought on a single iRule which is applied to all VS's that checks for a value in a datagroup would be a good way to implement this. Here is a simple, untested example:

when HTTP_REQUEST {

    Check if the global_maintenance_class's single name is 1 or 0
   if {[class element -name 0 global_maintenance_class] == 1}{

       Send the maintenance HTML with cache control headers set to prevent caching
      HTTP::respond 200 content {maintenance info here} Cache-Control No-Cache Pragma No-Cache
   }
}

It would be most efficient to only add this iRule when you want to send the maintenance response. Else, you'd need to do a datagroup lookup on every HTTP request to every VS. You could create a simple iControl app which adds the iRule to all VS's that is run either from a remote host or the LTM unit itself.

You could expand on this to example to serve HTML and images which the HTML reference. See the maintenance page examples in the Codeshare for details:

http://devcentral.f5.com/wiki/default.aspx/iRules/CodeShare.htmlUtility

(search for maintenance)

Aaron