How to switching URI roundrobin based on data-group list

Hi swjo,

to overwrite the HTTP::host value based on the currently selected pool member (aka. just for pool member X.X.X.119), you have to use the

HTTP_REQUEST_SEND

event (triggered after pool member selection), filter on the selected pool member IP and finaly change the HTTP::host value to a random value based on a mod(rand())^4 calculation followed by an array lookup to retrive the HTTP::host names...

when RULE_INIT {
    array set static::apisky {
        "0" "api31sky.whypaymore.co.kr"
        "1" "api32sky.whypaymore.co.kr"
        "2" "api33sky.whypaymore.co.kr"
        "3" "api34sky.whypaymore.co.kr"
    }

}
when HTTP_REQUEST_SEND {
    if { [LB::server addr] equals "X.X.X.119" } then {
        clientside {
            HTTP::host $static::apisky([expr { int( rand() * 100 ) % 4 }])
        }
    }
}

Note: The selection of the individual HTTP::host values in the example above is not a true "Round-Robin-Selection". Instead its more or less just a "Random-Selection". To implement a true "Round-Robin-Selection" you have to store a shared counter value into LTMs session-

[table]

so that each TMM core can access and also increase/rollover this information as needed. But in 9 out of 10 times a real "Round-Robin-Selection" isn't required and should therefor be avoided to save CPU cycles...

Cheers, Kai