diff --git a/hadoop-yarn-project/CHANGES.txt b/hadoop-yarn-project/CHANGES.txt
index b28f8f823fa..6a871a58a8b 100644
--- a/hadoop-yarn-project/CHANGES.txt
+++ b/hadoop-yarn-project/CHANGES.txt
@@ -70,6 +70,9 @@ Release 2.6.0 - UNRELEASED
     YARN-415. Capture aggregate memory allocation at the app-level for chargeback.
     (Eric Payne & Andrey Klochkov via jianhe)
 
+    YARN-2440. Enabled Nodemanagers to limit the aggregate cpu usage across all
+    containers to a preconfigured limit. (Varun Vasudev via vinodkv)
+
   IMPROVEMENTS
 
     YARN-2197. Add a link to YARN CHANGES.txt in the left side of doc
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java
index 7b7511d20b2..7c71a1717f1 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java
@@ -723,6 +723,12 @@ public class YarnConfiguration extends Configuration {
   /** Number of Virtual CPU Cores which can be allocated for containers.*/
   public static final String NM_VCORES = NM_PREFIX + "resource.cpu-vcores";
   public static final int DEFAULT_NM_VCORES = 8;
+
+  /** Percentage of overall CPU which can be allocated for containers. */
+  public static final String NM_RESOURCE_PERCENTAGE_PHYSICAL_CPU_LIMIT =
+      NM_PREFIX + "resource.percentage-physical-cpu-limit";
+  public static final int DEFAULT_NM_RESOURCE_PERCENTAGE_PHYSICAL_CPU_LIMIT =
+      100;
   
   /** NM Webapp address.**/
   public static final String NM_WEBAPP_ADDRESS = NM_PREFIX + "webapp.address";
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml
index 9b4a90f4790..04e458cd722 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml
@@ -871,12 +871,24 @@
   </property>
 
   <property>
-    <description>Number of CPU cores that can be allocated 
-    for containers.</description>
+    <description>Number of vcores that can be allocated
+    for containers. This is used by the RM scheduler when allocating
+    resources for containers. This is not used to limit the number of
+    physical cores used by YARN containers.</description>
     <name>yarn.nodemanager.resource.cpu-vcores</name>
     <value>8</value>
   </property>
 
+  <property>
+    <description>Percentage of CPU that can be allocated
+    for containers. This setting allows users to limit the amount of
+    CPU that YARN containers use. Currently functional only
+    on Linux using cgroups. The default is to use 100% of CPU.
+    </description>
+    <name>yarn.nodemanager.resource.percentage-physical-cpu-limit</name>
+    <value>100</value>
+  </property>
+
   <property>
     <description>NM Webapp address.</description>
     <name>yarn.nodemanager.webapp.address</name>
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/util/CgroupsLCEResourcesHandler.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/util/CgroupsLCEResourcesHandler.java
index d5bd22540f3..0b6c2ac60b3 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/util/CgroupsLCEResourcesHandler.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/util/CgroupsLCEResourcesHandler.java
@@ -33,6 +33,7 @@ import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
 import com.google.common.annotations.VisibleForTesting;
+import org.apache.commons.io.FileUtils;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.conf.Configuration;
@@ -42,6 +43,7 @@ import org.apache.hadoop.yarn.api.records.Resource;
 import org.apache.hadoop.yarn.conf.YarnConfiguration;
 import org.apache.hadoop.yarn.server.nodemanager.LinuxContainerExecutor;
 import org.apache.hadoop.yarn.util.Clock;
+import org.apache.hadoop.yarn.util.ResourceCalculatorPlugin;
 import org.apache.hadoop.yarn.util.SystemClock;
 
 public class CgroupsLCEResourcesHandler implements LCEResourcesHandler {
@@ -59,7 +61,11 @@ public class CgroupsLCEResourcesHandler implements LCEResourcesHandler {
   private final String MTAB_FILE = "/proc/mounts";
   private final String CGROUPS_FSTYPE = "cgroup";
   private final String CONTROLLER_CPU = "cpu";
+  private final String CPU_PERIOD_US = "cfs_period_us";
+  private final String CPU_QUOTA_US = "cfs_quota_us";
   private final int CPU_DEFAULT_WEIGHT = 1024; // set by kernel
+  private final int MAX_QUOTA_US = 1000 * 1000;
+  private final int MIN_PERIOD_US = 1000;
   private final Map<String, String> controllerPaths; // Controller -> path
 
   private long deleteCgroupTimeout;
@@ -106,8 +112,15 @@ public class CgroupsLCEResourcesHandler implements LCEResourcesHandler {
   }
   
   public void init(LinuxContainerExecutor lce) throws IOException {
+    this.init(lce,
+        ResourceCalculatorPlugin.getResourceCalculatorPlugin(null, conf));
+  }
+
+  @VisibleForTesting
+  void init(LinuxContainerExecutor lce, ResourceCalculatorPlugin plugin)
+      throws IOException {
     initConfig();
-    
+
     // mount cgroups if requested
     if (cgroupMount && cgroupMountPath != null) {
       ArrayList<String> cgroupKVs = new ArrayList<String>();
@@ -117,8 +130,74 @@ public class CgroupsLCEResourcesHandler implements LCEResourcesHandler {
     }
 
     initializeControllerPaths();
+
+    // cap overall usage to the number of cores allocated to YARN
+    float yarnProcessors =
+        NodeManagerHardwareUtils.getContainersCores(plugin, conf);
+    int systemProcessors = plugin.getNumProcessors();
+    if (systemProcessors != (int) yarnProcessors) {
+      LOG.info("YARN containers restricted to " + yarnProcessors + " cores");
+      int[] limits = getOverallLimits(yarnProcessors);
+      updateCgroup(CONTROLLER_CPU, "", CPU_PERIOD_US, String.valueOf(limits[0]));
+      updateCgroup(CONTROLLER_CPU, "", CPU_QUOTA_US, String.valueOf(limits[1]));
+    } else if (cpuLimitsExist()) {
+      LOG.info("Removing CPU constraints for YARN containers.");
+      updateCgroup(CONTROLLER_CPU, "", CPU_QUOTA_US, String.valueOf(-1));
+    }
   }
 
+  boolean cpuLimitsExist() throws IOException {
+    String path = pathForCgroup(CONTROLLER_CPU, "");
+    File quotaFile = new File(path, CONTROLLER_CPU + "." + CPU_QUOTA_US);
+    if (quotaFile.exists()) {
+      String contents = FileUtils.readFileToString(quotaFile, "UTF-8");
+      int quotaUS = Integer.parseInt(contents.trim());
+      if (quotaUS != -1) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  @VisibleForTesting
+  int[] getOverallLimits(float yarnProcessors) {
+
+    int[] ret = new int[2];
+
+    if (yarnProcessors < 0.01f) {
+      throw new IllegalArgumentException("Number of processors can't be <= 0.");
+    }
+
+    int quotaUS = MAX_QUOTA_US;
+    int periodUS = (int) (MAX_QUOTA_US / yarnProcessors);
+    if (yarnProcessors < 1.0f) {
+      periodUS = MAX_QUOTA_US;
+      quotaUS = (int) (periodUS * yarnProcessors);
+      if (quotaUS < MIN_PERIOD_US) {
+        LOG
+          .warn("The quota calculated for the cgroup was too low. The minimum value is "
+              + MIN_PERIOD_US + ", calculated value is " + quotaUS
+              + ". Setting quota to minimum value.");
+        quotaUS = MIN_PERIOD_US;
+      }
+    }
+
+    // cfs_period_us can't be less than 1000 microseconds
+    // if the value of periodUS is less than 1000, we can't really use cgroups
+    // to limit cpu
+    if (periodUS < MIN_PERIOD_US) {
+      LOG
+        .warn("The period calculated for the cgroup was too low. The minimum value is "
+            + MIN_PERIOD_US + ", calculated value is " + periodUS
+            + ". Using all available CPU.");
+      periodUS = MAX_QUOTA_US;
+      quotaUS = -1;
+    }
+
+    ret[0] = periodUS;
+    ret[1] = quotaUS;
+    return ret;
+  }
 
   boolean isCpuWeightEnabled() {
     return this.cpuWeightEnabled;
@@ -274,7 +353,7 @@ public class CgroupsLCEResourcesHandler implements LCEResourcesHandler {
     BufferedReader in = null;
 
     try {
-      in = new BufferedReader(new FileReader(new File(MTAB_FILE)));
+      in = new BufferedReader(new FileReader(new File(getMtabFileName())));
 
       for (String str = in.readLine(); str != null;
           str = in.readLine()) {
@@ -292,13 +371,13 @@ public class CgroupsLCEResourcesHandler implements LCEResourcesHandler {
         }
       }
     } catch (IOException e) {
-      throw new IOException("Error while reading " + MTAB_FILE, e);
+      throw new IOException("Error while reading " + getMtabFileName(), e);
     } finally {
       // Close the streams
       try {
         in.close();
       } catch (IOException e2) {
-        LOG.warn("Error closing the stream: " + MTAB_FILE, e2);
+        LOG.warn("Error closing the stream: " + getMtabFileName(), e2);
       }
     }
 
@@ -334,7 +413,12 @@ public class CgroupsLCEResourcesHandler implements LCEResourcesHandler {
       }
     } else {
       throw new IOException("Not able to enforce cpu weights; cannot find "
-          + "cgroup for cpu controller in " + MTAB_FILE);
+          + "cgroup for cpu controller in " + getMtabFileName());
     }
   }
+
+  @VisibleForTesting
+  String getMtabFileName() {
+    return MTAB_FILE;
+  }
 }
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/util/NodeManagerHardwareUtils.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/util/NodeManagerHardwareUtils.java
new file mode 100644
index 00000000000..07cf698429c
--- /dev/null
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/util/NodeManagerHardwareUtils.java
@@ -0,0 +1,79 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.hadoop.yarn.server.nodemanager.util;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.yarn.conf.YarnConfiguration;
+import org.apache.hadoop.yarn.util.ResourceCalculatorPlugin;
+
+@InterfaceAudience.Private
+@InterfaceStability.Unstable
+public class NodeManagerHardwareUtils {
+
+  /**
+   *
+   * Returns the fraction of CPU cores that should be used for YARN containers.
+   * The number is derived based on various configuration params such as
+   * YarnConfiguration.NM_RESOURCE_PERCENTAGE_PHYSICAL_CPU_LIMIT
+   *
+   * @param conf
+   *          - Configuration object
+   * @return Fraction of CPU cores to be used for YARN containers
+   */
+  public static float getContainersCores(Configuration conf) {
+    ResourceCalculatorPlugin plugin =
+        ResourceCalculatorPlugin.getResourceCalculatorPlugin(null, conf);
+    return NodeManagerHardwareUtils.getContainersCores(plugin, conf);
+  }
+
+  /**
+   *
+   * Returns the fraction of CPU cores that should be used for YARN containers.
+   * The number is derived based on various configuration params such as
+   * YarnConfiguration.NM_RESOURCE_PERCENTAGE_PHYSICAL_CPU_LIMIT
+   *
+   * @param plugin
+   *          - ResourceCalculatorPlugin object to determine hardware specs
+   * @param conf
+   *          - Configuration object
+   * @return Fraction of CPU cores to be used for YARN containers
+   */
+  public static float getContainersCores(ResourceCalculatorPlugin plugin,
+      Configuration conf) {
+    int numProcessors = plugin.getNumProcessors();
+    int nodeCpuPercentage =
+        Math.min(conf.getInt(
+          YarnConfiguration.NM_RESOURCE_PERCENTAGE_PHYSICAL_CPU_LIMIT,
+          YarnConfiguration.DEFAULT_NM_RESOURCE_PERCENTAGE_PHYSICAL_CPU_LIMIT),
+          100);
+    nodeCpuPercentage = Math.max(0, nodeCpuPercentage);
+
+    if (nodeCpuPercentage == 0) {
+      String message =
+          "Illegal value for "
+              + YarnConfiguration.NM_RESOURCE_PERCENTAGE_PHYSICAL_CPU_LIMIT
+              + ". Value cannot be less than or equal to 0.";
+      throw new IllegalArgumentException(message);
+    }
+
+    return (nodeCpuPercentage * numProcessors) / 100.0f;
+  }
+}
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/util/TestCgroupsLCEResourcesHandler.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/util/TestCgroupsLCEResourcesHandler.java
index 611045ea2d9..45068988045 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/util/TestCgroupsLCEResourcesHandler.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/util/TestCgroupsLCEResourcesHandler.java
@@ -17,13 +17,18 @@
  */
 package org.apache.hadoop.yarn.server.nodemanager.util;
 
+import org.apache.commons.io.FileUtils;
+import org.apache.hadoop.yarn.server.nodemanager.LinuxContainerExecutor;
+import org.apache.hadoop.yarn.util.ResourceCalculatorPlugin;
 import org.junit.Assert;
 import org.apache.hadoop.yarn.conf.YarnConfiguration;
 import org.apache.hadoop.yarn.util.Clock;
 import org.junit.Test;
+import org.mockito.Mockito;
 
-import java.io.File;
-import java.io.FileOutputStream;
+import java.io.*;
+import java.util.List;
+import java.util.Scanner;
 import java.util.UUID;
 import java.util.concurrent.CountDownLatch;
 
@@ -70,4 +75,142 @@ public class TestCgroupsLCEResourcesHandler {
     Assert.assertFalse(handler.deleteCgroup(file.getPath()));
   }
 
+  static class MockLinuxContainerExecutor extends LinuxContainerExecutor {
+    @Override
+    public void mountCgroups(List<String> x, String y) {
+    }
+  }
+
+  static class CustomCgroupsLCEResourceHandler extends
+      CgroupsLCEResourcesHandler {
+
+    String mtabFile;
+    int[] limits = new int[2];
+
+    @Override
+    int[] getOverallLimits(float x) {
+      return limits;
+    }
+
+    void setMtabFile(String file) {
+      mtabFile = file;
+    }
+
+    @Override
+    String getMtabFileName() {
+      return mtabFile;
+    }
+  }
+
+  @Test
+  public void testInit() throws IOException {
+    LinuxContainerExecutor mockLCE = new MockLinuxContainerExecutor();
+    CustomCgroupsLCEResourceHandler handler =
+        new CustomCgroupsLCEResourceHandler();
+    YarnConfiguration conf = new YarnConfiguration();
+    final int numProcessors = 4;
+    ResourceCalculatorPlugin plugin =
+        Mockito.mock(ResourceCalculatorPlugin.class);
+    Mockito.doReturn(numProcessors).when(plugin).getNumProcessors();
+    handler.setConf(conf);
+    handler.initConfig();
+
+    // create mock cgroup
+    File cgroupDir = new File("target", UUID.randomUUID().toString());
+    if (!cgroupDir.mkdir()) {
+      String message = "Could not create dir " + cgroupDir.getAbsolutePath();
+      throw new IOException(message);
+    }
+    File cgroupMountDir = new File(cgroupDir.getAbsolutePath(), "hadoop-yarn");
+    if (!cgroupMountDir.mkdir()) {
+      String message =
+          "Could not create dir " + cgroupMountDir.getAbsolutePath();
+      throw new IOException(message);
+    }
+
+    // create mock mtab
+    String mtabContent =
+        "none " + cgroupDir.getAbsolutePath() + " cgroup rw,relatime,cpu 0 0";
+    File mockMtab = new File("target", UUID.randomUUID().toString());
+    if (!mockMtab.exists()) {
+      if (!mockMtab.createNewFile()) {
+        String message = "Could not create file " + mockMtab.getAbsolutePath();
+        throw new IOException(message);
+      }
+    }
+    FileWriter mtabWriter = new FileWriter(mockMtab.getAbsoluteFile());
+    mtabWriter.write(mtabContent);
+    mtabWriter.close();
+    mockMtab.deleteOnExit();
+
+    // setup our handler and call init()
+    handler.setMtabFile(mockMtab.getAbsolutePath());
+
+    // check values
+    // in this case, we're using all cpu so the files
+    // shouldn't exist(because init won't create them
+    handler.init(mockLCE, plugin);
+    File periodFile = new File(cgroupMountDir, "cpu.cfs_period_us");
+    File quotaFile = new File(cgroupMountDir, "cpu.cfs_quota_us");
+    Assert.assertFalse(periodFile.exists());
+    Assert.assertFalse(quotaFile.exists());
+
+    // subset of cpu being used, files should be created
+    conf.setInt(YarnConfiguration.NM_RESOURCE_PERCENTAGE_PHYSICAL_CPU_LIMIT, 75);
+    handler.limits[0] = 100 * 1000;
+    handler.limits[1] = 1000 * 1000;
+    handler.init(mockLCE, plugin);
+    int period = readIntFromFile(periodFile);
+    int quota = readIntFromFile(quotaFile);
+    Assert.assertEquals(100 * 1000, period);
+    Assert.assertEquals(1000 * 1000, quota);
+
+    // set cpu back to 100, quota should be -1
+    conf.setInt(YarnConfiguration.NM_RESOURCE_PERCENTAGE_PHYSICAL_CPU_LIMIT, 100);
+    handler.limits[0] = 100 * 1000;
+    handler.limits[1] = 1000 * 1000;
+    handler.init(mockLCE, plugin);
+    quota = readIntFromFile(quotaFile);
+    Assert.assertEquals(-1, quota);
+
+    FileUtils.deleteQuietly(cgroupDir);
+  }
+
+  private int readIntFromFile(File targetFile) throws IOException {
+    Scanner scanner = new Scanner(targetFile);
+    if (scanner.hasNextInt()) {
+      return scanner.nextInt();
+    }
+    return -1;
+  }
+
+  @Test
+  public void testGetOverallLimits() {
+
+    int expectedQuota = 1000 * 1000;
+    CgroupsLCEResourcesHandler handler = new CgroupsLCEResourcesHandler();
+
+    int[] ret = handler.getOverallLimits(2);
+    Assert.assertEquals(expectedQuota / 2, ret[0]);
+    Assert.assertEquals(expectedQuota, ret[1]);
+
+    ret = handler.getOverallLimits(2000);
+    Assert.assertEquals(expectedQuota, ret[0]);
+    Assert.assertEquals(-1, ret[1]);
+
+    int[] params = { 0, -1 };
+    for (int cores : params) {
+      try {
+        handler.getOverallLimits(cores);
+        Assert.fail("Function call should throw error.");
+      } catch (IllegalArgumentException ie) {
+        // expected
+      }
+    }
+
+    // test minimums
+    ret = handler.getOverallLimits(1000 * 1000);
+    Assert.assertEquals(1000 * 1000, ret[0]);
+    Assert.assertEquals(-1, ret[1]);
+  }
 }
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/util/TestNodeManagerHardwareUtils.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/util/TestNodeManagerHardwareUtils.java
new file mode 100644
index 00000000000..e1af9483a89
--- /dev/null
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/util/TestNodeManagerHardwareUtils.java
@@ -0,0 +1,72 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.hadoop.yarn.server.nodemanager.util;
+
+import org.apache.hadoop.yarn.conf.YarnConfiguration;
+import org.apache.hadoop.yarn.util.ResourceCalculatorPlugin;
+import org.junit.Assert;
+import org.junit.Test;
+import org.mockito.Mockito;
+
+public class TestNodeManagerHardwareUtils {
+
+  @Test
+  public void testGetContainerCores() {
+
+    YarnConfiguration conf = new YarnConfiguration();
+    float ret;
+    final int numProcessors = 4;
+    ResourceCalculatorPlugin plugin =
+        Mockito.mock(ResourceCalculatorPlugin.class);
+    Mockito.doReturn(numProcessors).when(plugin).getNumProcessors();
+
+    conf.setInt(YarnConfiguration.NM_RESOURCE_PERCENTAGE_PHYSICAL_CPU_LIMIT, 0);
+    try {
+      NodeManagerHardwareUtils.getContainersCores(plugin, conf);
+      Assert.fail("getContainerCores should have thrown exception");
+    } catch (IllegalArgumentException ie) {
+      // expected
+    }
+
+    conf.setInt(YarnConfiguration.NM_RESOURCE_PERCENTAGE_PHYSICAL_CPU_LIMIT,
+      100);
+    ret = NodeManagerHardwareUtils.getContainersCores(plugin, conf);
+    Assert.assertEquals(4, (int) ret);
+
+    conf
+      .setInt(YarnConfiguration.NM_RESOURCE_PERCENTAGE_PHYSICAL_CPU_LIMIT, 50);
+    ret = NodeManagerHardwareUtils.getContainersCores(plugin, conf);
+    Assert.assertEquals(2, (int) ret);
+
+    conf
+      .setInt(YarnConfiguration.NM_RESOURCE_PERCENTAGE_PHYSICAL_CPU_LIMIT, 75);
+    ret = NodeManagerHardwareUtils.getContainersCores(plugin, conf);
+    Assert.assertEquals(3, (int) ret);
+
+    conf
+      .setInt(YarnConfiguration.NM_RESOURCE_PERCENTAGE_PHYSICAL_CPU_LIMIT, 85);
+    ret = NodeManagerHardwareUtils.getContainersCores(plugin, conf);
+    Assert.assertEquals(3.4, ret, 0.1);
+
+    conf.setInt(YarnConfiguration.NM_RESOURCE_PERCENTAGE_PHYSICAL_CPU_LIMIT,
+      110);
+    ret = NodeManagerHardwareUtils.getContainersCores(plugin, conf);
+    Assert.assertEquals(4, (int) ret);
+  }
+}