URL Distribution

Question

I received a request as to the possibility to or distribute traffic for one url to multiple urls (round-robin, least connections, or even just randomly ) but never exceed 50 connections to each one. I am struggling to find the best way to do this, if even feasible. This would not be sending to different pools/server, but to different "forms" on the same server/pool. Any guidance anyone can provide would be greatly appreciated.Here is an a visual&nbsp; example of what they are trying to accomplish:https://forms.dummywebsite.com/form would distribute traffic to the following without without a redirect or end user noticing a url change in their browser.&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &gt; &nbsp; &nbsp; &nbsp; https://forms.dummywebsite.com/form1&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &gt; &nbsp; &nbsp; &nbsp; https://forms.dummywebsite.com/form2&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &gt; &nbsp; &nbsp; &nbsp; https://forms.dummywebsite.com/form3https://forms.dummywebsite.com/form&nbsp; &nbsp; &nbsp; &nbsp; &gt; &nbsp; &nbsp; &nbsp; https://forms.dummywebsite.com/form4&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &gt; &nbsp; &nbsp; &nbsp; https://forms.dummywebsite.com/form5&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &gt; &nbsp; &nbsp; &nbsp; https://forms.dummywebsite.com/form6&nbsp;It would be required that each form would never more that 50 connections. I have found a potential irule&nbsp; candidate pasted below from another post (thanks The_Bhatmann - distribute-load-based-on-uri) that contains a counter that may be able to be adjusted for this, but not sure it really fits the bill. It would need to monitor all the connections to make sure each connection has not exceeded 50 before more traffic is sent to it. All my other google-foo has failed.&nbsp;when RULE_INIT {&nbsp; &nbsp;set counter 0}when CLIENT_ACCEPTED {&nbsp; &nbsp; if {$::counter &lt;= 7} {&nbsp; &nbsp; &nbsp;The first 7 connections go to Server A for URI 1&nbsp; &nbsp; &nbsp; pool &nbsp;member &nbsp;&nbsp; &nbsp; &nbsp; incr $::counter&nbsp; &nbsp;} elseif {$::counter &lt;= 10 } {&nbsp; &nbsp; &nbsp; The next 3 connections go to server B for URI 2&nbsp; &nbsp; &nbsp; pool &nbsp;member &nbsp;&nbsp; &nbsp; &nbsp; incr $::counter&nbsp; &nbsp;} else {&nbsp; &nbsp; &nbsp;Reset the counter when 11th connection is reached and go to SERVER A for URI 1&nbsp; &nbsp; &nbsp;set $::counter 0&nbsp; &nbsp; &nbsp; pool &nbsp;member &nbsp;&nbsp; &nbsp;}} &nbsp;&nbsp;&nbsp;Thanks for any help/Guidance. Any input is much appreciated

jrahm · Accepted Answer

Not at all tested or optimized or secured against injection with the table commands, but to get the juices flowing I threw this together. Not 100% confident it'll work and I don't have time until end of the week to flesh out and test, but it is possible to achieve what you're after. That said, it'll be a support nightmare to grow with the needs of the business since it's not a well-defined problem or scale, so I would push back against this particular ask.
when HTTP_REQUEST priority 500 {
    if { [string tolower [HTTP::path]] == "/form"} {
        foreach form [list form1 form2 form3 form4 form5 form6] {
            if { [table lookup $form] &lt; 50 } {
                table incr $form 1
                HTTP::uri /$form
                set current_form $form
                break
            }
        }
    }
}
when HTTP_REQUEST priority 501 {
    if { [string tolower [HTTP::path]] == "/form" } {
        HTTP::respond 429 content "&lt;html&gt;&lt;body&gt;&lt;p&gt;All forms at max of 50 requests&lt;/p&gt;&lt;/body&gt;&lt;/html&gt;" 
    }
}
when HTTP_RESPONSE {
    table incr $current_form -1
}
&nbsp;

walkman69 · Answer

Hi JRahm!Thanks for the reply and the heads-up on the example.&nbsp; At this point the number of forms will be static, but of course as the business needs, that could change in the future. Yes, as the connections bleed from the forms new requests can be sent to them.

jrahm · Answer

hi walkman69 is the number of forms static or dynamic? For example, is the list form1 -&gt; form6, and therefore 300 connections max, or just form1 -&gt; form(n) and incrementing every 50 connections? If the latter, as connections bleed from previous forms, do you want to send new requests to those?
&nbsp;
Also I should mention that example is very old. Logic isn't bad, but the use of global variables is, and pins all requests for that virtual server to a single TMM.

daniel_wolf · Answer

Hi walkman69,
I am randomly guessing, that each form1-6 is server by a different pool member. If my assumption is right, you can set a session limit per node and use Least Connections method for load balancing.
root@(awaf)(cfg-sync Standalone)(Active)(/Common)(tmos)# list ltm node 10.0.2.50 
ltm node 10.0.2.50 {
    address 10.0.2.50
    connection-limit 50
}

Then I would do the URL rewriting on the web server in the backend. Doing application logic on the BIG-IP is possible, but sometimes it's just... meh... Uti, non abuti.
Maybe you can explain your requirements a bit more in details, so we can suggest a better solution.
KRDaniel
&nbsp;

walkman69 · Answer

Hi Daniel_Wolf! This is not node/member specific. All forms will reside on all servers in the same pool(s) and those servers it is just this one particular form/webpage that needs this type of distribution as the servers also handle traffic for other websites, so the connection limit cannot be set on a node basis. I definitely agree this is something that should be done on the web server itself, the dev team just wants to explore all options.

walkman69 · Answer

Thanks JRahm! I think this is a good enough jumping off point. I greatly appreciate it. I firmly believe the F5 is not he right place for what they are trying to do, but they asked. I will definitely advise against it.

Forum Discussion

URL Distribution

6 Replies

Recent Discussions

Disk space full - what files, folders are safe to delete?

ASM instance creation

BIG-IP DNS: Check Status Of Multiple Monitors Against Pool Member

Open Redirection Mitigation

F5Access | MacOS Sonoma

Related Content

F5 Distributed Cloud - Listener Logic

F5 Distributed Cloud Bot Defense Protecting AWS CloudFront Distributions

Minimizing Security Complexity: Managing Distributed WAF Policies

F5 Distributed Cloud Origin Server Subset Rules

F5 Distributed Cloud and AWS VPC Lattice