Forum Discussion

Robberhines_120's avatar
Robberhines_120
Icon for Nimbostratus rankNimbostratus
Jul 14, 2016

Have Passive monitor iRule skipped if url contains

We are trying to setup a passive iRule that will mark a load balanced member down if it gets a number of errors from the server. I found an example of one and it seems to work OK however our developers stated that some of the API calls the develop can return a 500 error and that is to be expected. Luckily all the API stuff is under a /services/ url. Is there an easy way to take the code below and have it just exit the rule if the url contains /services/ in the url?

 

when HTTP_REQUEST {
   if { not [info exists orig_request]} {
       set orig_request [HTTP::request]
   }
 }
when HTTP_RESPONSE {
    if { [HTTP::status] >= 500 } {
       set failures [session lookup dest_addr [LB::server addr]]
      if { $failures >= 3 } {
          LB::down
        log local0.warning "Pool member down for '[LB::server addr]' - May want to investigate"  
       } else {
          session add dest_addr [LB::server addr] [incr failures]
         LB::detach
         HTTP::retry $orig_request
       }
   }
}

Reference URL:

 

F5 Friday - Eavesdropping on avialability

 

application delivery
iRules

3 Replies

Sort By
  • jgranieri's avatar
    jgranieri
    Icon for Nimbostratus rankNimbostratus
    Jul 14, 2016

    Perhaps adding something like this will allow the traffic to continue on. It would be another if statement in your existing code

     

    when HTTP_REQUEST {
    if { [HTTP::uri] contains "/services/ url" } {
        default pool XYZ
     }
    }
  • VernonWells's avatar
    VernonWells
    Icon for Employee rankEmployee
    Jul 14, 2016

    You could, at the top of HTTP_RESPONSE, do the following:

     

    when HTTP_RESPONSE {
    if { [HTTP::path] starts_with "/services/" } {
        return
    }
        
    ... all of your code here ...
}

     

    Alternatively, you could wrap all of your code in a negating if:

     

    when HTTP_RESPONSE {
    if { not ([HTTP::path] starts_with "/services/") } {
        ... all of your code in here ...
    }
}

     

  • Robberhines_120's avatar
    Robberhines_120
    Icon for Nimbostratus rankNimbostratus
    Jul 14, 2016

    As a side comment, I seem to be getting a TCL error when trying to increment:

     

    TCL error: /common/count_server_down  - expected integer but got "" while executing "incr failures"

     

    I have since found this F5 Solution: F5 - SOL7440 Is one solution better than another?

Related Content