Previously, we explained the Worker Module Source Code Analysis: How DolphinScheduler Achieves Billion-Level Task Scheduling. Today, let's explore the principles of the Master module source code. Master Slot Calculation Located in org.apache.dolphinscheduler.server.master.registry.MasterSlotManager.SlotChangeListener#notify public void notify(Map<String, MasterHeartBeat> masterNodeInfo) { List<Server> serverList = masterNodeInfo.values().stream() // TODO This filters out busy master nodes.