HTTP::cookie, SWITCH and multiple identical pools

Just apply a persistence cookie profile to your virtual

Then the iRule would be;-

when HTTP_REQUEST {
    foreach ck [HTTP::cookie names] {
        if {$ck starts_with "BIGipServer"} {
             Select pool based on part of cookie name
            pool [substr $ck 11]
             Drop out of event - F5 will choose appropriate pool member based on cookie
            return
        }   
    }   
    switch -glob [string tolower [HTTP::path]] {
        "/pool_a*" {
            HTTP::path "/"
            pool "pool_a" } 
        "/pool_b*" {
            HTTP::path "/"
            pool "pool_b" }
        "/pool_c*" {
            HTTP::path "/"
            pool "pool_c" } 
        "/pool_d*" {
            HTTP::path "/"
            pool "pool_d" } 
        default { reject }
       } 
    }
}

Thank you for your response. Your code did what I asked but unfortunately my logic was faulty. After testing, we discovered that if a user needed to access the information in more than one of the pools, the BigIP cookies from previous queries would direct queries to incorrect pools. So it appears that I need to remove the pool name strings from the URIs or PATHs during HTTP requests and add them back in during HTTP responses based upon the pool which processed the request. I am not sure how to accomplish this request.

 when HTTP_REQUEST
 switch -glob [string tolower [HTTP::path]] {
    "/pool_a*" {
        set lbpath HTTP::path
        HTTP::path "/"
        pool "pool_a" } 
    "/pool_b*" {
        set lbpath HTTP::path
        HTTP::path "/"
        pool "pool_b" }
    "/pool_c*" {
        set lbpath HTTP::path
        HTTP::path "/"
        pool "pool_c" } 
    "/pool_d*" {
        set lbpath HTTP::path
        HTTP::path "/"
        pool "pool_d" } 
    default { reject }
   } 

   when HTTP_RESPONSE
   switch -glob [string tolower $lbpath ] {
    "/pool_a*" {
        HTTP::path "/pool_a/[HTTP::path]" } 
    "/pool_b*" {
        HTTP::path "/pool_b/[HTTP::path]" }
    "/pool_c*" {
        HTTP::path "/pool_c/[HTTP::path]" } 
    "/pool_d*" {
        HTTP::path "/pool_d/[HTTP::path]" } 
    default { reject }
   } 

add them back in during HTTP responses based upon the pool which processed the request.

request uri is not in http response. to make it clearer, have you ever used http analyzer tool such as httpfox? it can show you how http request and response look like.

httpfox

about the irule, can't we just move persist cookie command inside switch case? e.g.

 config

[root@ve11a:Active:In Sync] config  tmsh list ltm virtual bar
ltm virtual bar {
    destination 172.28.24.10:80
    ip-protocol tcp
    mask 255.255.255.255
    persist {
        cookie {
            default yes
        }
    }
    profiles {
        http { }
        tcp { }
    }
    rules {
        qux
    }
    source 0.0.0.0/0
    source-address-translation {
        type automap
    }
    vs-index 5
}
[root@ve11a:Active:In Sync] config  tmsh list ltm rule qux
ltm rule qux {
    when HTTP_REQUEST {
  switch -glob [HTTP::path] {
    "/pool_a/*" {
      HTTP::path [string map {/pool_a/ /} [HTTP::path]]
      persist cookie
      pool pool_a
    }
    "/pool_b/*" {
      HTTP::path [string map {/pool_b/ /} [HTTP::path]]
      persist cookie
      pool pool_b
    }
    default {
      reject
    }
  }
}
}

 test (sending request wrong cookie but the right pool is picked up - can see from response cookie)

[root@ve11a:Active:In Sync] config  curl -I http://172.28.24.10/pool_a/ -H "Cookie: BIGipServerpool_b=1875429576.20480.0000"
HTTP/1.1 200 OK
Date: Fri, 18 Apr 2014 08:04:06 GMT
Server: Apache/2.2.3 (CentOS)
Last-Modified: Sun, 09 Feb 2014 08:39:51 GMT
ETag: "41879c-59-2a9c23c0"
Accept-Ranges: bytes
Content-Length: 89
Content-Type: text/html; charset=UTF-8
Set-Cookie: BIGipServerpool_a=1707657416.20480.0000; path=/

[root@ve11a:Active:In Sync] config  curl -I http://172.28.24.10/pool_b/ -H "Cookie: BIGipServerpool_a=1707657416.20480.0000"
HTTP/1.1 200 OK
Date: Fri, 18 Apr 2014 08:05:22 GMT
Server: Apache/2.2.3 (CentOS)
Last-Modified: Tue, 23 Apr 2013 06:46:40 GMT
ETag: "418432-4b-8c2c3400"
Accept-Ranges: bytes
Content-Length: 75
Content-Type: text/html; charset=UTF-8
Set-Cookie: BIGipServerpool_b=1875429576.20480.0000; path=/