YARN-7678. Ability to enable logging of container memory stats. Contributed by Jim Brennan

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/monitor/ContainersMonitorImpl.java

@@ -59,6 +59,8 @@ public class ContainersMonitorImpl extends AbstractService implements
 
   private final static Logger LOG =
        LoggerFactory.getLogger(ContainersMonitorImpl.class);
+  private final static Logger AUDITLOG =
+       LoggerFactory.getLogger(ContainersMonitorImpl.class.getName()+".audit");
 
   private long monitoringInterval;
   private MonitoringThread monitoringThread;
@@ -595,8 +597,8 @@ public class ContainersMonitorImpl extends AbstractService implements
               * maxVCoresAllottedForContainers /nodeCpuPercentageForYARN);
       long vmemLimit = ptInfo.getVmemLimit();
       long pmemLimit = ptInfo.getPmemLimit();
-      if (LOG.isDebugEnabled()) {
-        LOG.debug(String.format(
+      if (AUDITLOG.isDebugEnabled()) {
+        AUDITLOG.debug(String.format(
                 "Memory usage of ProcessTree %s for container-id %s: ",
                 pId, containerId.toString()) +
                 formatUsageString(