Most efficient way to re-prioritize a virtual server's iRules?

Hi ML,

Here's a little trick that might help. All iRules have a global priority and their individual events have priorities as well. By default, this priority is 500 if it is not defined in the iRule. If no priority are defined, then the iRules are executed based on the order in the web UI. If a lower priority (say 100) is defined for an iRule or its events, they will be executed before those with lower priorities regardless of their position in the list. There is a fair amount of documentation on the priority command in the DevCentral iRules Wiki.

What I would do is just set a higher priority for the maintenance iRule and then just add it to begin maintenance,and delete it from the virtual server to end maintenance. The iRule might look like this:

priority 100

when HTTP_REQUEST {
    HTTP::redirect "http://mysite.com/maintenance.html"
}

You can then just use the LocalLB::VirtualServer::add_rule and LocalLB::VirtualServer::remove_rule methods to add and delete the iRule. You can put the iRule in any order and it should always fire first.

Hope that helps,

-George