iRule - A lot of urls with single VIP

Question

Hi gents&nbsp;
I need to create a iRule for multiple urls with single VIP.
Could you please let me get your knowledge?&nbsp;
The following is the URL structure.&nbsp;
*.(application)-(environment).test.com&nbsp;
The examples of URLs requested by users are; &nbsp;
test10.test-t10.test.com&nbsp;
test20.test_api-t10.test.com&nbsp;
testbranch11.lab-t10.test.com&nbsp;
testbranch22.lab_api-t10.test.com&nbsp;
The first part of URL like "test10", "test20" can change anytime.&nbsp;
We have mutiple servers from T10 to T20. More servers(T21, T22...) will be added later&nbsp;
According to the server number, the urls will be like the followings.&nbsp;
[T10]&nbsp;
*.test-t10.test.com&nbsp;
*.test_api-t10.test.com &nbsp;
*.lab-t10.test.com&nbsp;
*.lab_api-t10.test.com &nbsp;
[T11]&nbsp;
*.test-t11.test.com&nbsp;
*.test_api-t11.test.com &nbsp;
*.lab-t11.test.com&nbsp;
*.lab_api-t11.test.com &nbsp;
The other servers(T12 to T20) will provide internet service with the same URL patterns above.&nbsp;
After F5 LTM checks HTTP request, LTM will load balance to a proper pool.&nbsp;
[exmaple]&nbsp;
*.test-t10.test.com   ==&gt; Go to pool named "PL_test-t10.test.com"&nbsp;
*.test_api-t10.test.com ==&gt; Go to pool named "PL_test_api-T10.test.com"&nbsp;
*.lab-t10.test.com ==&gt; Go to pool named "PL_lab-t10.test.com"&nbsp;
*.lab_api-t10.test.com ==&gt; Go to pool named "PL_lab_api-t10.test.com"&nbsp;
*.test-t11.test.com   ==&gt; Go to pool named "PL_test-t11.test.com"&nbsp;
*.test_api-t11.test.com ==&gt; Go to pool named "PL_test_api-T11.test.com"&nbsp;
*.lab-t11.test.com ==&gt; Go to pool named "PL_lab-t11.test.com"&nbsp;
*.lab_api-t11.test.com ==&gt; Go to pool named "PL_lab_api-t11.test.com"&nbsp;
The other servers from T12 to T20 will be the same load balancing patterns.&nbsp;
I have created a rule for this request.
Could you please advise me if this irule works correctly? 
The main idea of the iRUle is that I do not want to update the iRule when any server is added to the load balancing pool.&nbsp;
[iRule]&nbsp;
when HTTP_REQUEST {
                if {[scan [string tolower [HTTP::host]] "test-t%2d.test.com" boxnumber] == 1 } {
       pool "PL_test-T${boxnumber}.test.com"
                                  unset boxnumber
                                }&nbsp;
elseif {[scan [string tolower [HTTP::host]] "test_api-t%2d.test.com" boxnumber] == 1 } {
        pool "PL_test_api-T${boxnumber}.test.com"
                             unset boxnumber
                    }&nbsp;
elseif {[scan [string tolower [HTTP::host]] "lab-t%2d.test.com" boxnumber] == 1 } {
        pool "PL_lab-T${boxnumber}.test.com"
                             unset boxnumber
                    }&nbsp;
elseif {[scan [string tolower [HTTP::host]] "lab_api-t%2d.test.com" boxnumber] == 1 } {
        pool "PL_lab_api-T${boxnumber}.test.com"
                             unset boxnumber
                    } 
}&nbsp;

michael__ · Answer

Hi,
You can also use ltm policies (prior 11.4 http classes) instead of an irule to accomplish this&nbsp;
Regards&nbsp;
Michael&nbsp;

chad_p_17647 · Answer

Richard,
Like Michael said you can you policies in 11.4 and up.
https://support.f5.com/kb/en-us/solutions/public/15000/000/sol15085.html
In an iRule you can do it many ways but using the switch is cleaner and will be more efficient.
Something like:
when HTTP_REQUEST {
                set http_host [string tolower [HTTP::host]]
                set pool1 "poola"
                set pool2 "poolb"
                set pool3 "poolc"
                set default "default_pool"
                switch -glob [$http_host] {
                  "*.test.a.com" {
                               pool $pool1
                   }
                   "*.test.b.com" -
                   "b.com" {
                               pool $pool2
                   } 
                   "www.c.com" {
                                pool $pool3
                   }
                   default {
                              pool $default         
                   }
        }
}

Switch:  https://devcentral.f5.com/articles/irules-101-04-switch
-Chad

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iRule - A lot of urls with single VIP

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