irules that load balance http redirects

This should work.

when CLIENT_ACCEPTED {
    set redirect_urls {"http://sitea.example.com" "http://siteb.example.com"}
    set redirect_url [lindex $redirect_urls [expr {[table incr [virtual]_count] % [llength $redirect_urls]}]]
}

when HTTP_REQUEST {
    HTTP::redirect $redirect_url
}

Inspired by a code snippet from Chad Jenison. See:

• https://devcentral.f5.com/codeshare/better-round-robin-1023