call function on member howto

Hi

I have 2 pools defined in clientCache.xml file,

I have total 4 gemfire members or jvm up and running, i want to execute function on each member (not on region or pool)

i am able to execute function on the pool by getting all pools like below,

But when i try

com.gemstone.gemfire.cache.execute.FunctionException: Function named XXXX.MyFunction is not registered to FunctionService

I want to bascially execute this function on each member or JVM or gemfire