Select a pool member based on URI and remove the URI info

Hi!

Thanks for providing this information.

My guess is you have issue with persistence : Remember by default the persistence is attached to the TCP session and persistence data are not parsed for each HTTP request. Nowaday a lot of browser is keeping it's TCP session alive and reuse it to pass multiple HTTP get request. This mean that if you come with a new persistence cookie in a TCP connection wich already get tied to a node, your will be send to the old persist node until you get a new TCP connection (by fully close and restart your browser for example)

Issue number 2 is when you target a Node in your Irule you probably don't set a persist cooki for this node and the next request will determine your persist node.

You can check if all request goes to the good node by using the "developers tools" of your browser and check for your persist cookie you should see that the reply for request to example.com/server1 does not contains a set-cookie for your persist cookie.

To solve this you can try the following :

• Create an irule to force persist-cookie evaluation for each request (so if your tcp session is tied to server3 and you go to /server1 the following request will be forward according to the new cookie. The content of the rule is quite simple :

when HTTP_REQUEST {
        catch {LB::detach}
}

• Next you need to handle /server1 and /server2 uri... This can be done easily with policy. Policy are much easier than irule and well optimised => anything that can be done with policy should be done with policy rather than irule. See the following screenshot for the policy config :

Just change :

• Node IP/port with your value
• CookieName with your actual persist cookie name
• Value : you can use this tool https://www.nooby.fr/pages/f5-cookie-encode-decode.php to convert your node IP:port to actual cooki value.

I did lab this set up with a dummy APM policy (just a per session permit all) an it is working fine on Big-ip v15.1.3

Regards,