Forum Discussion

myself_85560's avatar
myself_85560
Icon for Nimbostratus rankNimbostratus
Jun 01, 2016

LB decisions matching the headers

Hi, We have a custom written application that is being hosted on multiple servers behind the LTM. It does not use cookies rather a variety of unique http headers. I need to use these unique headers to make load balancing decisions.

 

Below first set of headers that should hit the pool_1

 

TEST/Rumba/mountainisred@4

 

TEST/Rumba/mountainisblue@2

 

TEST/Rumba/mountainisorange@2

 

TEST/Rumba/mountainisgreen@2

 

Below second set of headers that should hit the pool_2

 

TEST/Rumba/mountainispink@2

 

TEST/Rumba/mountainisgray@2

 

TEST/Rumba/mountainiswhite@2

 

TEST/Rumba/mountainisblack@2

 

Traffic with none of the above headers to hit a default_pool pool_3

 

Here is my iRule:

 

when HTTP_REQUEST { if { [HTTP::header value mountainisred@4} {

 

pool pool_1 } else {

 

pool main_pool

 

} }

 

Your response is much appreciated.

 

Thanks

 

application delivery
iRules
LTM
  • Yann_Desmarest_'s avatar
    Yann_Desmarest_
    Jun 02, 2016

    Hi,

    I would recommend the modified irule below, changed second if by elseif. Otherwise, If you match the first if you also match the else and you will have a tcl error and a tcp reset on thz client side :

    when HTTP_REQUEST {
if { [class match [HTTP::header "online.protocol.remote.contenttype"] equals header_value_1] } {
        pool_1
    }
elseif { [class match [HTTP::header "online.protocol.remote.contenttype"] equals header_value_2] } {
        pool_2
    } 
    else {
        pool_3
    }
   }
  • Yann_Desmarest's avatar
    Yann_Desmarest
    Icon for Cirrus rankCirrus
    Jun 01, 2016

    Hi,

    You can take the below irule as example, I assumed that you were talking about uri not headers but correct me if I'm wrong : 

    when HTTP_REQUEST {
    switch -glob [HTTP::uri] {
        "*TEST/Rumba/mountainisred@4*" -
        "*TEST/Rumba/mountainisblue@2*" -
        "*TEST/Rumba/mountainisorange@2*" -
        "*TEST/Rumba/mountainisgreen@2*" {
            pool_1
        }
        "*TEST/Rumba/mountainispink@2*" -
        "*TEST/Rumba/mountainisgray@2*" -
        "*TEST/Rumba/mountainiswhite@2*" -
        "*TEST/Rumba/mountainisblack@2*" {
            pool_2
        }
        default {
            pool_3
        }

    }
}
    • myself_85560's avatar
      myself_85560
      Icon for Nimbostratus rankNimbostratus
      Jun 01, 2016
      Thanks Yann for your quick response. Nope. Its not the uri but headers. I am sure. I have seen the headers. The headers has 3 or 4 lines of unique strings. I took out one of them, that are widely looks a similar type across all the headers. Does that makes any difference if it is a POST rather than a GET.
  • Yann_Desmarest_'s avatar
    Yann_Desmarest_
    Icon for Nacreous rankNacreous
    Jun 01, 2016

    Hi,

    You can take the below irule as example, I assumed that you were talking about uri not headers but correct me if I'm wrong : 

    when HTTP_REQUEST {
    switch -glob [HTTP::uri] {
        "*TEST/Rumba/mountainisred@4*" -
        "*TEST/Rumba/mountainisblue@2*" -
        "*TEST/Rumba/mountainisorange@2*" -
        "*TEST/Rumba/mountainisgreen@2*" {
            pool_1
        }
        "*TEST/Rumba/mountainispink@2*" -
        "*TEST/Rumba/mountainisgray@2*" -
        "*TEST/Rumba/mountainiswhite@2*" -
        "*TEST/Rumba/mountainisblack@2*" {
            pool_2
        }
        default {
            pool_3
        }

    }
}
    • myself_85560's avatar
      myself_85560
      Icon for Nimbostratus rankNimbostratus
      Jun 01, 2016
      Thanks Yann for your quick response. Nope. Its not the uri but headers. I am sure. I have seen the headers. The headers has 3 or 4 lines of unique strings. I took out one of them, that are widely looks a similar type across all the headers. Does that makes any difference if it is a POST rather than a GET.
  • myself_85560's avatar
    myself_85560
    Icon for Nimbostratus rankNimbostratus
    Jun 01, 2016

    Hi Yann,

     

    One of the header looks something like this.

     

    POST /online/vendorlink/protocol/3 HTTP/1.1

     

    Content-Type: application/x-onl-pki-smime

     

    online.protocol.remote.contenttype: TEST/Rumba/mountainisred@4

     

    Cache-Control: no-cache

     

    Pragma: no-cache

     

    User-Agent: Java/1.7.0_25

     

    Host: host1.abc.com

     

    Accept: text/html, image/gif, image/jpeg, *; q=.2, /; q=.2

     

    Connection: keep-alive

     

    Content-Length: 5836

     

    thanks

     

  • Yann_Desmarest_'s avatar
    Yann_Desmarest_
    Icon for Nacreous rankNacreous
    Jun 01, 2016

    Hi,

     

    So you can change the [HTTP::uri] command in the switch by [HTTP::header "online.protocol.remote.contenttype"]

     

    • myself_85560's avatar
      myself_85560
      Icon for Nimbostratus rankNimbostratus
      Jun 01, 2016
      Will this one work as well? [HTTP::header "mountainisred@4"] Please advise. thanks
    • myself_85560's avatar
      myself_85560
      Icon for Nimbostratus rankNimbostratus
      Jun 01, 2016
      Hi Yann, ignore me. Yes ,it is the name and value match. I got it. thanks
  • Yann_Desmarest's avatar
    Yann_Desmarest
    Icon for Cirrus rankCirrus
    Jun 01, 2016

    Hi,

     

    So you can change the [HTTP::uri] command in the switch by [HTTP::header "online.protocol.remote.contenttype"]

     

    • myself_85560's avatar
      myself_85560
      Icon for Nimbostratus rankNimbostratus
      Jun 01, 2016
      Will this one work as well? [HTTP::header "mountainisred@4"] Please advise. thanks
    • myself_85560's avatar
      myself_85560
      Icon for Nimbostratus rankNimbostratus
      Jun 01, 2016
      Hi Yann, ignore me. Yes ,it is the name and value match. I got it. thanks
  • myself_85560's avatar
    myself_85560
    Icon for Nimbostratus rankNimbostratus
    Jun 01, 2016

    Hi,

     

    Can we supply or pass the header values from a txt file, into the iRule. The txt file to contain all the header values, tab limited etc. using internal data-group? and be made available to the iRules?

     

    Please advise how I can achieve it.

     

    thanks

     

    • Yann_Desmarest's avatar
      Yann_Desmarest
      Icon for Cirrus rankCirrus
      Jun 01, 2016
      Hi, you can pass a datagroup file by using the following command 'class match [HTTP::header "online.protocol.remote.contenttype"] equals header_value'. header_value is the name of your datagroup.
    • Yann_Desmarest's avatar
      Yann_Desmarest
      Icon for Cirrus rankCirrus
      Jun 01, 2016
      But using datagroup, you can't use the switch anymore, you have to use if instead.
  • myself_85560's avatar
    myself_85560
    Icon for Nimbostratus rankNimbostratus
    Jun 02, 2016

    Hi Yann,

    See below. I came out with an iRule. Would this be OK. Please respond. Much appriciated.

    These are string data-groups; header_value_1 & header_value_2 

    when HTTP_REQUEST {
if { [class match [HTTP::header "online.protocol.remote.contenttype"] equals header_value_1] } {
        pool_1
    }
if { [class match [HTTP::header "online.protocol.remote.contenttype"] equals header_value_2] } {
        pool_2
    } 
    else {
        pool_3
    }
   }
  • Yann_Desmarest_'s avatar
    Yann_Desmarest_
    Icon for Nacreous rankNacreous
    Jun 02, 2016

    Hi,

    I would recommend the modified irule below, changed second if by elseif. Otherwise, If you match the first if you also match the else and you will have a tcl error and a tcp reset on thz client side :

    when HTTP_REQUEST {
if { [class match [HTTP::header "online.protocol.remote.contenttype"] equals header_value_1] } {
        pool_1
    }
elseif { [class match [HTTP::header "online.protocol.remote.contenttype"] equals header_value_2] } {
        pool_2
    } 
    else {
        pool_3
    }
   }
  • Yann_Desmarest's avatar
    Yann_Desmarest
    Icon for Cirrus rankCirrus
    Jun 02, 2016

    Hi,

    I would recommend the modified irule below, changed second if by elseif. Otherwise, If you match the first if you also match the else and you will have a tcl error and a tcp reset on thz client side :

    when HTTP_REQUEST {
if { [class match [HTTP::header "online.protocol.remote.contenttype"] equals header_value_1] } {
        pool_1
    }
elseif { [class match [HTTP::header "online.protocol.remote.contenttype"] equals header_value_2] } {
        pool_2
    } 
    else {
        pool_3
    }
   }