import org.apache.hadoop.yarn.server.resourcemanager.monitor.SchedulingMonitor; //导入依赖的package包/类
@Test
public void testPolicyInitializeAfterSchedulerInitialized() {
  @SuppressWarnings("resource")
  MockRM rm = new MockRM(conf);
  rm.init(conf);
  
  // ProportionalCapacityPreemptionPolicy should be initialized after
  // CapacityScheduler initialized. We will 
  // 1) find SchedulingMonitor from RMActiveService's service list, 
  // 2) check if ResourceCalculator in policy is null or not. 
  // If it's not null, we can come to a conclusion that policy initialized
  // after scheduler got initialized
  for (Service service : rm.getRMActiveService().getServices()) {
    if (service instanceof SchedulingMonitor) {
      ProportionalCapacityPreemptionPolicy policy =
          (ProportionalCapacityPreemptionPolicy) ((SchedulingMonitor) service)
              .getSchedulingEditPolicy();
      assertNotNull(policy.getResourceCalculator());
      return;
    }
  }
  
  fail("Failed to find SchedulingMonitor service, please check what happened");
}
 

import org.apache.hadoop.yarn.server.resourcemanager.monitor.SchedulingMonitor; //导入依赖的package包/类
protected void createPolicyMonitors() {
  if (scheduler instanceof PreemptableResourceScheduler
      && conf.getBoolean(YarnConfiguration.RM_SCHEDULER_ENABLE_MONITORS,
      YarnConfiguration.DEFAULT_RM_SCHEDULER_ENABLE_MONITORS)) {
    LOG.info("Loading policy monitors");
    List<SchedulingEditPolicy> policies = conf.getInstances(
        YarnConfiguration.RM_SCHEDULER_MONITOR_POLICIES,
        SchedulingEditPolicy.class);
    if (policies.size() > 0) {
      for (SchedulingEditPolicy policy : policies) {
        LOG.info("LOADING SchedulingEditPolicy:" + policy.getPolicyName());
        // periodically check whether we need to take action to guarantee
        // constraints
        SchedulingMonitor mon = new SchedulingMonitor(rmContext, policy);
        addService(mon);
      }
    } else {
      LOG.warn("Policy monitors configured (" +
          YarnConfiguration.RM_SCHEDULER_ENABLE_MONITORS +
          ") but none specified (" +
          YarnConfiguration.RM_SCHEDULER_MONITOR_POLICIES + ")");
    }
  }
}
 

import org.apache.hadoop.yarn.server.resourcemanager.monitor.SchedulingMonitor; //导入依赖的package包/类
protected void createPolicyMonitors() {
  if (scheduler instanceof PreemptableResourceScheduler
      && conf.getBoolean(YarnConfiguration.RM_SCHEDULER_ENABLE_MONITORS,
      YarnConfiguration.DEFAULT_RM_SCHEDULER_ENABLE_MONITORS)) {
    LOG.info("Loading policy monitors");
    List<SchedulingEditPolicy> policies = conf.getInstances(
        YarnConfiguration.RM_SCHEDULER_MONITOR_POLICIES,
        SchedulingEditPolicy.class);
    if (policies.size() > 0) {
      rmDispatcher.register(ContainerPreemptEventType.class,
          new RMContainerPreemptEventDispatcher(
              (PreemptableResourceScheduler) scheduler));
      for (SchedulingEditPolicy policy : policies) {
        LOG.info("LOADING SchedulingEditPolicy:" + policy.getPolicyName());
        // periodically check whether we need to take action to guarantee
        // constraints
        SchedulingMonitor mon = new SchedulingMonitor(rmContext, policy);
        addService(mon);
      }
    } else {
      LOG.warn("Policy monitors configured (" +
          YarnConfiguration.RM_SCHEDULER_ENABLE_MONITORS +
          ") but none specified (" +
          YarnConfiguration.RM_SCHEDULER_MONITOR_POLICIES + ")");
    }
  }
}
 

import org.apache.hadoop.yarn.server.resourcemanager.monitor.SchedulingMonitor; //导入依赖的package包/类
protected void createPolicyMonitors() {
  if (scheduler instanceof PreemptableResourceScheduler
      && conf.getBoolean(YarnConfiguration.RM_SCHEDULER_ENABLE_MONITORS,
        YarnConfiguration.DEFAULT_RM_SCHEDULER_ENABLE_MONITORS)) {
    LOG.info("Loading policy monitors");
    List<SchedulingEditPolicy> policies = conf.getInstances(
            YarnConfiguration.RM_SCHEDULER_MONITOR_POLICIES,
            SchedulingEditPolicy.class);
    if (policies.size() > 0) {
      this.rmDispatcher.register(ContainerPreemptEventType.class,
        new RMContainerPreemptEventDispatcher(
          (PreemptableResourceScheduler) scheduler));
      for (SchedulingEditPolicy policy : policies) {
        LOG.info("LOADING SchedulingEditPolicy:" + policy.getPolicyName());
        policy.init(conf, this.rmContext.getDispatcher().getEventHandler(),
            (PreemptableResourceScheduler) scheduler);
        // periodically check whether we need to take action to guarantee
        // constraints
        SchedulingMonitor mon = new SchedulingMonitor(policy);
        addService(mon);

      }
    } else {
      LOG.warn("Policy monitors configured (" +
          YarnConfiguration.RM_SCHEDULER_ENABLE_MONITORS +
          ") but none specified (" +
          YarnConfiguration.RM_SCHEDULER_MONITOR_POLICIES + ")");
    }
  }
}
 

import org.apache.hadoop.yarn.server.resourcemanager.monitor.SchedulingMonitor; //导入依赖的package包/类
protected void createPolicyMonitors() {
  if (scheduler instanceof PreemptableResourceScheduler
      && conf.getBoolean(YarnConfiguration.RM_SCHEDULER_ENABLE_MONITORS,
      YarnConfiguration.DEFAULT_RM_SCHEDULER_ENABLE_MONITORS)) {
    LOG.info("Loading policy monitors");
    List<SchedulingEditPolicy> policies = conf.getInstances(
        YarnConfiguration.RM_SCHEDULER_MONITOR_POLICIES,
        SchedulingEditPolicy.class);
    if (policies.size() > 0) {
      rmDispatcher.register(ContainerPreemptEventType.class,
          new RMContainerPreemptEventDispatcher(
              (PreemptableResourceScheduler) scheduler));
      for (SchedulingEditPolicy policy : policies) {
        LOG.info("LOADING SchedulingEditPolicy:" + policy.getPolicyName());
        policy.init(conf, rmContext.getDispatcher().getEventHandler(),
            (PreemptableResourceScheduler) scheduler);
        // periodically check whether we need to take action to guarantee
        // constraints
        SchedulingMonitor mon = new SchedulingMonitor(policy);
        addService(mon);
      }
    } else {
      LOG.warn("Policy monitors configured (" +
          YarnConfiguration.RM_SCHEDULER_ENABLE_MONITORS +
          ") but none specified (" +
          YarnConfiguration.RM_SCHEDULER_MONITOR_POLICIES + ")");
    }
  }
}