irule to select pool based on url

Here's a quick iRule example:

when HTTP_REQUEST {
    switch -gob [string tolower [HTTP::uri]] {
        "/dashboard*" { pool pool_B }
        "/" { pool pool_A }
        default { pool pool_A }
    }
}

But then you can also do this task with an LTM policy and no iRules at all. Remember to enable OneConnect in the virtual server and in the associated HTTP profile to be able to do this context-based load balancing.