Hadoop metrics can be only sent to the first ganglia gmond server

Ganglia metrics can be only sent to the first metric server.
If I config namenode.sink.ganglia.servers=host1:8649,host2:8649 in hadoop-metrics2.properties,then metrics can only be sent to host1,host2 will never receive them.This means if gmond on host1 is down,metrics will not be collected.

This happens because GangliaSink parse metric servers use a getString method in SubsetConfiguration,while this method return only the first element in the list.