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Manasi_Sathe_10's avatar
Manasi_Sathe_10
Icon for Nimbostratus rankNimbostratus
Dec 15, 2006

Reading the host header and directing to the corresponding pool

I want to write a general i-rule for multiple websites such that on reading the url it pools the right pool. for eg:

 

 

say i have a couple of url's say 1.abc.xyz.com

 

2. ptr.xyz.com

 

 

and they each have their assosiated pool.. now i want to write a general i-rule that i don't need to update everytime i have a new website..something on the lines of

 

 

when HTTP_REQUEST { if { [HTTP::host] matches_regex "*.xyz.com" }{pool *.xyz.com} }

 

 

 

or any ideas how to use switch statements in irules??

 

 

Thanks

 

 

 

 

application delivery
dev
devops
iRules

1 Reply

  • hoolio's avatar
    hoolio
    Icon for Cirrostratus rankCirrostratus
    Dec 15, 2006

    You can check the TCL man pages for details on standard TCL commands:

    Click here

    For F5-specific commands, check the iRules wiki

    Click here

    Try this post to start with: Click here

    You could combine that example with this one to set the host to lower case before you make the host header comparison: Click here

    Putting those together, here's an example which uses switch with the glob flag (for string comparisons). This is less resource intensive than using a regex to do the comparisons. 

    
when HTTP_REQUEST {
   switch -glob [string tolower [HTTP::host]] {
      *example.com -
      *site1.example.net -
      *site2* {
         pool first_pool
      }
      *site3* -
      *site4* {
         pool second_pool
      }
      default {
         pool default_pool
      }
   }
}

    You can check the iRules wiki page for switch for details on this (Click here)

    If you want to debug this, you could add log statements and check the /var/log/ltm log file. Here's an example for logging:

    log local0. "client: [IP::client_addr] matched first switch case"

    Aaron