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BaltoStar_12467's avatar
BaltoStar_12467
Oct 01, 2013

possible to have multi-layered irules ?

I need to make changes to an existing prod instance of F5 BIG-IP LTM VE 10.2.4.

 

It has a virtual server configured with a single iRule that contains 2 simple switch statements that parse host & uri and route to various pools.

 

For switch case ( pool ) , I need to add some redirect/rewrite functionality.

 

I would prefer not to alter the existing Rule - or alter it as little as possible.

 

Is it possible to "layer in" another irule ? So if the first irule gets to the switch case it routes to another irule ?

 

Alternately , is it possible to attach an irule to the destination pool so that it intercepts all traffic routed to that pool ?

 

application delivery
cloud
design
devops
iRules
vmware

1 Reply

  • JRahm's avatar
    JRahm
    Icon for Admin rankAdmin
    Oct 01, 2013

    yes, you could do something like that by using variables to do so. I would be careful at the maintainability of such a solution. But basically:

    Rule 1

    priority 100
when RULE_INIT {
  set static::trigger 0
}
when HTTP_REQUEST {
  switch [LB::server pool] {
    "pool1" { set static::trigger 1 }
    "pool2" { set static::trigger 2 }
    "pool3" { set static::trigger 3 }
  }
}

    Pool1 Rule

    priority 110
when HTTP_REQUEST {
  if { $static::trigger == 1 } {
    do stuff
  }
}

    Edit->actually, LB::server pool probably won't be very accurate in HTTP_REQUEST, so you might need to move some of the logic to a later event. The flow from iRule->iRule mapping stands though.