Moving traffic from VIP to VIP

Hi Sekharchandra,

 

I guess you will run into all kind of persistence problems trying to let 90% traffic get through to the primary site and pick 10% to be distributed via redirect.

 

The virtual server needs a criteria to differentiate between clients with a local connection an new requests. This could be a cookie to be evaluated with the initial client request.

 

To simplify things I just enhanced my proposed solution by a third direction. So the distribution schema follows Brads approach of 18:1:1.

 

when RULE_INIT {
     set servername to use for responses (default will be "BIGip"), turned off with "noserver" switch in HTTP::respond
    set static::srvname "ServerLB"
     set redirect code (301=moved permanently, 302=moved temporarily)
    set static::statcode 301
     set server ratio values
    set static::ratioA 18
    set static::ratioB 1
    set static::ratioC 1
     set server hostnames
    set static::hostA "www.serverA.bit"
    set static::hostB "www.serverB.bit"
    set static::hostC "www.serverC.bit"
     activate logging (0=disabled, 1=enabled)
    set static::debugRatioLb 1
}

when HTTP_REQUEST {
    if { [expr {[table incr req_counter]%[expr {$static::ratioA+$static::ratioB$static::ratioC}]}] < $static::ratioA } {
         values from 0 to less than ratioA will be directed to serverA
        if { $static::debugRatioLb > 0 } {
            log local0. "total counter: <[table lookup req_counter]>; modulo <[expr {[table lookup req_counter]%[expr {$static::ratioA+$static::ratioB+$static::ratioC}]}]> match ratio <$static::ratioA>"
        }
        HTTP::respond $static::statcode noserver server $static::srvname Location http://$static::hostA[HTTP::uri]
        return
    } elseif { [expr {[table incr req_counter]%[expr {$static::ratioA+$static::ratioB$static::ratioC}]}] < [expr {$static::ratioA+$static::ratioB}]} {
         values greater than ratioA and less than ratioA + ratioB will be directed to serverB
        if { $static::debugRatioLb > 0 } {
            log local0. "total counter: <[table lookup req_counter]>; modulo <[expr {[table lookup req_counter]%[expr {$static::ratioA+$static::ratioB+$static::ratioC}]}]> match ratio <$static::ratioB>"
        }
        HTTP::respond $static::statcode noserver server $static::srvname Location http://$static::hostB[HTTP::uri]
        return
    } else {
         values greater than ratioA  + ratioB will be directed to serverC
        if { $static::debugRatioLb > 0 } {
            log local0. "total counter: <[table lookup req_counter]>; modulo <[expr {[table lookup req_counter]%[expr {$static::ratioA+$static::ratioB+$static::ratioC}]}]> match ratio <$static::ratioC>"
        }
        HTTP::respond $static::statcode noserver server $static::srvname Location http://$static::hostC[HTTP::uri]
        return
    }
}

Thanks, Stephan

 

PS: Reposted due to broken formatting