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Eric_Frankenfie's avatar
Eric_Frankenfie
Icon for Nimbostratus rankNimbostratus
Nov 07, 2016

iRule vs. Local Traffic Policy vs. Rewrite Profile

Rewrite URI and send to specific pool/node.

 

I have a pool with 6 members which is applied to a virtual server. Our support team would like to have the ability to test against each of the 6 members individual to determine the performance of each member.

 

VS: app.example.com_443_vs

 

Pool: app.example.com_443_pool

 

Nodes: node[x].company.com

 

Host: https://app.example.com

 

URI: /myApp

 

I have decided to publish internally https://app.example.com/n[x]/myApp where x is each of the six members. In the past, I would have written an iRule to rewrite /n[x]/myapp to /myApp and select the pool/node based on /n[x], but now I have Local Traffic Policies and Rewrite Profiles at my disposal.

 

My question is should I perform the rewrite and pool/node selection in an iRule or is it more efficient to utilize a local traffic policy to perform those functions?

 

application delivery
iRules
LTM

3 Replies

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  • Vijay_E's avatar
    Vijay_E
    Icon for Cirrus rankCirrus
    Nov 07, 2016

    It is your choice. I prefer iRules for the flexibility. If you have already done similar such iRules, I would recommend sticking with iRules.

     

  • Eric_Frankenfie's avatar
    Eric_Frankenfie
    Icon for Nimbostratus rankNimbostratus
    Nov 07, 2016

    This is the iRule I created. Do you recommend using IF or CASE statements, or does it not matter?

    when HTTP_REQUEST { 
    if { [HTTP::uri] starts_with "/n1" } { 
        HTTP::path "/myApp" 
        pool n1-app.example.com_443_pool
    } elseif { [HTTP::uri] starts_with "/n2" } { 
        HTTP::path "/myApp" 
        pool n2-app.example.com_443_pool
    } elseif { [HTTP::uri] starts_with "/n3" } { 
        HTTP::path "/myApp" 
        pool n3-app.example.com_443_pool
    } elseif { [HTTP::uri] starts_with "/n4" } { 
        HTTP::path "/myApp" 
        pool n4-app.example.com_443_pool
    } elseif { [HTTP::uri] starts_with "/n5" } { 
        HTTP::path "/myApp" 
        pool n5-app.example.com_443_pool
    } elseif { [HTTP::uri] starts_with "/n6" } { 
        HTTP::path "/myApp" 
        pool n6-app.example.com_443_pool
    } else {
        pool app.example.com_443_pool
    }
}
  • VernonWells's avatar
    VernonWells
    Icon for Employee rankEmployee
    Nov 09, 2016

    You also asked about 

    if
    vs. 
    switch
    . For a multi-case conditional like you have above, you should definitely use 
    switch
    . In this case, it's simply because it will only evaluate 
    HTTP::uri
    once, rather than for each branch. In the worst case for your rule, it will evaluate 6 times.