Simple iRule to route to particular pools based upton a specific header value.

Hi viziony , 

Could you please try this : 

when HTTP_REQUEST {
if { [HTTP::header "Toggle"] equals "YES" }{
    pool pool_A
} else {
    pool pool_B
   }
}
#you can replace "equals" operator by "contains"

Try it and give me your feedback 
hope this helps you. 

Hi viziony  - it looks like you gave a kudo to Mohamed_Ahmed_Kansoh 's reply, so I'm going to mark that as the Accepted Solution to make it easier for someone else to see the answer. If that answer didn't help you, please let me know so I can change that status. 🙂