YARN-4857. Add missing default configuration regarding preemption of CapacityScheduler. Contributed by Kai Sasaki.

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml

@@ -908,6 +908,64 @@
     <value>600000</value>
   </property>
 
+  <property>
+    <description>
+    If true, run the policy but do not affect the cluster with preemption and kill events.
+    </description>
+    <name>yarn.resourcemanager.monitor.capacity.preemption.observe_only</name>
+    <value>false</value>
+  </property>
+
+  <property>
+    <description>
+    Time in milliseconds between invocations of this ProportionalCapacityPreemptionPolicy
+    policy.
+    </description>
+    <name>yarn.resourcemanager.monitor.capacity.preemption.monitoring_interval</name>
+    <value>3000</value>
+  </property>
+
+  <property>
+    <description>
+    Time in milliseconds between requesting a preemption from an application and killing
+    the container.
+    </description>
+    <name>yarn.resourcemanager.monitor.capacity.preemption.max_wait_before_kill</name>
+    <value>15000</value>
+  </property>
+
+  <property>
+    <description>
+    Maximum percentage of resources preempted in a single round. By controlling this valueone
+    can throttle the pace at which containers are reclaimed from the cluster. After computing
+    the total desired preemption, the policy scales it back within this limit.
+    </description>
+    <name>yarn.resourcemanager.monitor.capacity.preemption.total_preemption_per_round</name>
+    <value>0.1</value>
+  </property>
+
+  <property>
+    <description>
+    Maximum amount of resources above the target capacity ignored for preemption.
+    This defines a deadzone around the target capacity that helps prevent thrashing and
+    oscillations around the computed target balance. High values would slow the time to capacity
+    and (absent natural.completions) it might prevent convergence to guaranteed capacity.
+    </description>
+    <name>yarn.resourcemanager.monitor.capacity.preemption.max_ignored_over_capacity</name>
+    <value>0.1</value>
+  </property>
+
+  <property>
+    <description>
+    Given a computed preemption target, account for containers naturally expiring and preempt
+    only this percentage of the delta. This determines the rate of geometric convergence into
+    the deadzone (MAX_IGNORED_OVER_CAPACITY). For example, a termination factor of 0.5 will reclaim
+    almost 95% of resources within 5 * #WAIT_TIME_BEFORE_KILL, even absent natural termination.
+    </description>
+    <name>yarn.resourcemanager.monitor.capacity.preemption.natural_termination_factor</name>
+    <value>0.2</value>
+  </property>
+
   <!-- Node Manager Configuration -->
 
   <property>