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iinoue_38219's avatar
iinoue_38219
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Aug 29, 2011

Universal Persistence for URI String

I am a newbie of iRules. My system is BIG-IP 10.2.1.

 

I would like to loadbalance across two virtual-servers based on URI string.

 

 

 

 

First, a server reply HTTP_RESPONSE with "ticket=123...." in Location header.

 

 

 

Next, a client sends HTTP_REQUEST with "ticket=123...." in Request URI to another virtual-server (but pool member is same) .

 

 

 

The "ticket=123...." is persistence key which is unique across the two virtual-servers sessions.

 

 

 

 

 

 

Those two sessions must be loadbalanced to the same servers.

 

 

 

Does anyone have similar environment with me?

 

Or can provide me any iRule sample to do this?

 

 

 

 

 

 

Thanks

 

 

 

 

 

 

 

 

 

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  • The_Bhattman's avatar
    The_Bhattman
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    Aug 29, 2011
    Hi Innoue,

     

    If you have 2 virtual servers but share the same IP address then yes you can share the same persistance profile and match it across the 2 virtualls.

     

     

    However, when it comes to 2 separate Virtual IP addresses then I think Election HASH iRule applied to both virtuals might do the trick

     

     

    Here is the code

     

    
  Election Hash iRule 
 Compute Hash - MD5 
 
 MD5 calculation of Server + URI 
 Rule selects Server that scores highest 
 
 S = Current high score 
 N = Node being evaluated 
 W = Winning node 
 
when HTTP_REQUEST timing on {
 set S "" 
 foreach N [active_members -list ] { 
 if { [md5 $N [URI::query [HTTP::uri]] ticket] > $S } {
 set S [md5 $N[HTTP::uri]] 
 set W $N
 }
 }
 pool  member [lindex $W 0] [lindex $W 1]
}

     

     

     

    You can find more details about it on the following link

     

    http://devcentral.f5.com/wiki/iRules.ElectionHashLoadBalancingAndPersistence.ashx

     

     

    I hope this helps

     

    Bhattman

     

     

     

  • iinoue_38219's avatar
    iinoue_38219
    Icon for Nimbostratus rankNimbostratus
    Aug 31, 2011
    Thanks, Bhattman.

     

     

    In my case, virtuals don't have the same IP.

     

     

    And, First Session is the "Reply" from one server , whose Location header includes "ticket=1,2,3...".

     

    Next Session is the "Request" to another virtual server , whose Request URI includes "ticket1,2,3..."

     

     

    So, this might need universal persistence.But Election HASH iRule may be useful in another case.

     

     

    Thanks
  • iinoue_38219's avatar
    iinoue_38219
    Icon for Nimbostratus rankNimbostratus
    Aug 31, 2011
    Thanks, Bhattman.

     

     

    In my case, virtuals don't have the same IP.

     

     

    And, First Session is the "Reply" from one server , whose Location header includes "ticket=1,2,3...".

     

    Next Session is the "Request" to another virtual server , whose Request URI includes "ticket1,2,3..."

     

     

    So, this might need universal persistence.But Election HASH iRule may be useful in another case.

     

     

    Thanks