title: Hadoop 2.6.0 does not work reduce tasks in WordCount example
body: <p>I've installed Hadoop Cluster Setup on Multiple Nodes (physical). 
  I have one server for NameNode, ResourceManager and JobHistory server.
  I have two servers for DataNodes. I followed <a href="http://hadoop.apache.org/docs/current/hadoop-project-dist/hadoop-common/ClusterSetup.html" rel="nofollow noreferrer">this tutorial</a> while configuring.</p>
  
  <p>I tried to test MapReduce programs, such as WordCount, Terasoft, Teragen and etc, all i can launch from <code>hadoop/share/hadoop/mapreduce/hadoop-mapreduce-examples-2.6.0.jar</code></p>
  
  <p>So, Teragen and randomwriter i launch and they completed with success status (because there are no Reduce tasks, only Map tasks), but when i tried launch WordCount or WordMean, Map tasks completed (1 task), but Reduce 0% all the time. It is just stop completing. In <code>yarn-root-resourcemanager-yamaster.log</code> after success Map tasks i see only one row:</p>
  
  <pre><code>INFO org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler: Null container completed...
  </code></pre>
  
  <p>I tried to find out solution and i've found <a href="https://stackoverflow.com/questions/10165549/hadoop-wordcount-example-stuck-at-map-100-reduce-0">similar question on SOF,</a> but there are no correct answer, actually i don't know how to see free reducers in resource manager. What i have:</p>
  
  <ul>
  <li>Hadoop Web Interface: master:50070 </li>
  <li>Resource manager: master:8088</li>
  <li>JobHistory Server: master:19888/jobhistory</li>
  </ul>
  
  <p><strong>UPDATE:</strong>
  I try to launch wordcount example program without reduce tasks using key -D mapd.reduce.tasks=0:</p>
  
  <pre><code>hadoop jar hadoop-mapreduce-examples-2.6.0.jar wordcount -D mapd.reduce.tasks=0 /bigtext.txt /bigtext_wc_1.txt
  </code></pre>
  
  <p>And it works. I got wordcount result. It's wrong, coz no reduce, but my program completed.</p>
  
  <pre><code>15/02/03 12:40:37 INFO mapreduce.Job: Running job: job_1422950901990_0004
  15/02/03 12:40:52 INFO mapreduce.Job: Job job_1422950901990_0004 running in uber mode : false
  15/02/03 12:40:52 INFO mapreduce.Job:  map 0% reduce 0%
  15/02/03 12:41:03 INFO mapreduce.Job:  map 100% reduce 0%
  15/02/03 12:41:04 INFO mapreduce.Job: Job job_1422950901990_0004 completed successfully
  15/02/03 12:41:05 INFO mapreduce.Job: Counters: 30
  </code></pre>
  
  <p>UPDATE #2:</p>
  
  <p>More information from application log:</p>
  
  <pre><code>2015-02-03 15:02:12,008 INFO [IPC Server handler 0 on 55452] org.apache.hadoop.mapred.TaskAttemptListenerImpl: Progress of TaskAttempt attempt_1422959549820_0005_m_000000_0 is : 1.0
  2015-02-03 15:02:12,025 INFO [IPC Server handler 1 on 55452] org.apache.hadoop.mapred.TaskAttemptListenerImpl: Done acknowledgement from attempt_1422959549820_0005_m_000000_0
  2015-02-03 15:02:12,028 INFO [AsyncDispatcher event handler] org.apache.hadoop.mapreduce.v2.app.job.impl.TaskAttemptImpl: attempt_1422959549820_0005_m_000000_0 TaskAttempt Transitioned from RUNNING to SUCCESS_CONTAINER_CLEANUP
  2015-02-03 15:02:12,029 INFO [ContainerLauncher #1] org.apache.hadoop.mapreduce.v2.app.launcher.ContainerLauncherImpl: Processing the event EventType: CONTAINER_REMOTE_CLEANUP for container container_1422959549820_0005_01_000002 taskAttempt attempt_1422959549820_0005_m_000000_0
  2015-02-03 15:02:12,030 INFO [ContainerLauncher #1] org.apache.hadoop.mapreduce.v2.app.launcher.ContainerLauncherImpl: KILLING attempt_1422959549820_0005_m_000000_0
  2015-02-03 15:02:12,030 INFO [ContainerLauncher #1] org.apache.hadoop.yarn.client.api.impl.ContainerManagementProtocolProxy: Opening proxy : slave102.hadoop.ot.ru:51573
  2015-02-03 15:02:12,063 INFO [AsyncDispatcher event handler] org.apache.hadoop.mapreduce.v2.app.job.impl.TaskAttemptImpl: attempt_1422959549820_0005_m_000000_0 TaskAttempt Transitioned from SUCCESS_CONTAINER_CLEANUP to SUCCEEDED
  2015-02-03 15:02:12,084 INFO [AsyncDispatcher event handler] org.apache.hadoop.mapreduce.v2.app.job.impl.TaskImpl: Task succeeded with attempt attempt_1422959549820_0005_m_000000_0
  2015-02-03 15:02:12,087 INFO [AsyncDispatcher event handler] org.apache.hadoop.mapreduce.v2.app.job.impl.TaskImpl: task_1422959549820_0005_m_000000 Task Transitioned from RUNNING to SUCCEEDED
  2015-02-03 15:02:12,094 INFO [AsyncDispatcher event handler] org.apache.hadoop.mapreduce.v2.app.job.impl.JobImpl: Num completed Tasks: 1
  2015-02-03 15:02:12,792 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Before Scheduling: PendingReds:1 ScheduledMaps:0 ScheduledReds:0 AssignedMaps:1 AssignedReds:0 CompletedMaps:1 CompletedReds:0 ContAlloc:1 ContRel:0 HostLocal:1 RackLocal:0
  2015-02-03 15:02:12,794 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Recalculating schedule, headroom=&lt;memory:4096, vCores:-1&gt;
  2015-02-03 15:02:12,794 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Reduce slow start threshold reached. Scheduling reduces.
  2015-02-03 15:02:12,795 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: All maps assigned. Ramping up all remaining reduces:1
  2015-02-03 15:02:12,795 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: After Scheduling: PendingReds:0 ScheduledMaps:0 ScheduledReds:1 AssignedMaps:1 AssignedReds:0 CompletedMaps:1 CompletedReds:0 ContAlloc:1 ContRel:0 HostLocal:1 RackLocal:0
  2015-02-03 15:02:13,805 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerRequestor: getResources() for application_1422959549820_0005: ask=1 release= 0 newContainers=0 finishedContainers=1 resourcelimit=&lt;memory:6144, vCores:0&gt; knownNMs=4
  2015-02-03 15:02:13,806 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Received completed container container_1422959549820_0005_01_000002
  2015-02-03 15:02:13,808 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: After Scheduling: PendingReds:0 ScheduledMaps:0 ScheduledReds:1 AssignedMaps:0 AssignedReds:0 CompletedMaps:1 CompletedReds:0 ContAlloc:1 ContRel:0 HostLocal:1 RackLocal:0
  2015-02-03 15:02:13,808 INFO [AsyncDispatcher event handler] org.apache.hadoop.mapreduce.v2.app.job.impl.TaskAttemptImpl: Diagnostics report from attempt_1422959549820_0005_m_000000_0: Container killed by the ApplicationMaster.
  Container killed on request. Exit code is 143
  Container exited with a non-zero exit code 143
  </code></pre>
  
  <p>Configuration files of cluster.</p>
  
  <p>hdfs-site.xml</p>
  
  <pre><code>&lt;configuration&gt;
  &lt;!-- Properties for NameNode --&gt;
      &lt;property&gt;
          &lt;name&gt;dfs.namenode.name.dir&lt;/name&gt;
          &lt;value&gt;/grid/hadoop1/nn&lt;/value&gt;
          &lt;description&gt;Path on the local filesystem where the NameNode stores the namespace and transactions logs persistently. If this is a comma-delimited list of directories then the name table is replicated in all of the directories, for redundancy.&lt;/description&gt;
      &lt;/property&gt;
      &lt;property&gt;
              &lt;name&gt;dfs.namenode.hosts&lt;/name&gt;
              &lt;value&gt;/opt/current/hadoop/etc/hadoop/slaves&lt;/value&gt;
              &lt;description&gt;List of permitted DataNodes.If necessary, use these files to control the list of allowable datanodes.&lt;/description&gt;
      &lt;/property&gt;
      &lt;property&gt;
              &lt;name&gt;dfs.namenode.hosts.exclude&lt;/name&gt;
              &lt;value&gt;/opt/current/hadoop/etc/hadoop/excludes&lt;/value&gt;
              &lt;description&gt;List of excluded DataNodes. If necessary, use these files to control the list of allowable datanodes.&lt;/description&gt;
      &lt;/property&gt;
      &lt;property&gt;
              &lt;name&gt;dfs.blocksize&lt;/name&gt;
              &lt;value&gt;268435456&lt;/value&gt;
              &lt;description&gt;HDFS blocksize of 256MB for large file-systems.&lt;/description&gt;
      &lt;/property&gt;
      &lt;property&gt;
              &lt;name&gt;dfs.namenode.handler.count&lt;/name&gt;
              &lt;value&gt;100&lt;/value&gt;
              &lt;description&gt;More NameNode server threads to handle RPCs from large number of DataNodes.&lt;/description&gt;
      &lt;/property&gt;
  
  &lt;!-- Properties for DataNode --&gt;
      &lt;property&gt;
              &lt;name&gt;dfs.datanode.data.dir&lt;/name&gt;
              &lt;value&gt;/grid/hadoop1/dn&lt;/value&gt;
              &lt;description&gt;Comma separated list of paths on the local filesystem of a DataNode where it should store its blocks. If this is a comma-delimited list of directories, then data will be stored in all named directories, typically on different devices.&lt;/description&gt;
      &lt;/property&gt;
  &lt;/configuration&gt;
  </code></pre>
  
  <p>core-site.xml</p>
  
  <pre><code>&lt;configuration&gt;
      &lt;property&gt;
          &lt;name&gt;fs.defaultFS&lt;/name&gt;
          &lt;value&gt;hdfs://master:8020&lt;/value&gt;
          &lt;description&gt;Default hdfs filesystem on namenode host like - hdfs://host:port/&lt;/description&gt;
      &lt;/property&gt;
      &lt;property&gt;
          &lt;name&gt;io.file.buffer.size&lt;/name&gt;
          &lt;value&gt;131072&lt;/value&gt;
          &lt;description&gt;Size of read/write buffer used in SequenceFiles.&lt;/description&gt;
      &lt;/property&gt;
  &lt;/configuration&gt;
  </code></pre>
  
  <p>mapred-site.xml</p>
  
  <pre><code>&lt;configuration&gt;
  &lt;!-- Configurations for MapReduce Applications --&gt;        
          &lt;property&gt;
                  &lt;name&gt;mapreduce.framework.name&lt;/name&gt;
                  &lt;value&gt;yarn&lt;/value&gt;
                  &lt;description&gt;Execution framework set to Hadoop YARN.&lt;/description&gt;
          &lt;/property&gt;
          &lt;property&gt;
                  &lt;name&gt;mapreduce.map.memory.mb&lt;/name&gt;
                  &lt;value&gt;1536&lt;/value&gt;
                  &lt;description&gt;Larger resource limit for maps.&lt;/description&gt;
          &lt;/property&gt;
          &lt;property&gt;
                  &lt;name&gt;mapreduce.map.java.opts&lt;/name&gt;
                  &lt;value&gt;-Xmx1024M&lt;/value&gt;
                  &lt;description&gt;Larger heap-size for child jvms of maps.&lt;/description&gt;
          &lt;/property&gt;
          &lt;property&gt;
                  &lt;name&gt;mapreduce.reduce.memory.mb&lt;/name&gt;
                  &lt;value&gt;3072&lt;/value&gt;
                  &lt;description&gt;Larger resource limit for reduces.&lt;/description&gt;
          &lt;/property&gt;
          &lt;property&gt;
                  &lt;name&gt;mapreduce.reduce.java.opts&lt;/name&gt;
                  &lt;value&gt;-Xmx2560M&lt;/value&gt;
                  &lt;description&gt;Larger heap-size for child jvms of reduces.&lt;/description&gt;
          &lt;/property&gt;
          &lt;property&gt;
                  &lt;name&gt;mapreduce.task.io.sort.mb&lt;/name&gt;
                  &lt;value&gt;512&lt;/value&gt;
                  &lt;description&gt;Higher memory-limit while sorting data for efficiency.&lt;/description&gt;
          &lt;/property&gt;
          &lt;property&gt;
                  &lt;name&gt;mapreduce.task.io.sort.factor&lt;/name&gt;
                  &lt;value&gt;100&lt;/value&gt;
                  &lt;description&gt;More streams merged at once while sorting files.&lt;/description&gt;
          &lt;/property&gt;
          &lt;property&gt;
                  &lt;name&gt;mapreduce.reduce.shuffle.parallelcopies&lt;/name&gt;
                  &lt;value&gt;50&lt;/value&gt;
                  &lt;description&gt;Higher number of parallel copies run by reduces to fetch outputs from very large number of maps.&lt;/description&gt;
          &lt;/property&gt;
  &lt;!-- Configurations for MapReduce JobHistory Server --&gt;
          &lt;property&gt;
                  &lt;name&gt;mapreduce.jobhistory.address&lt;/name&gt;
                  &lt;value&gt;master:10020&lt;/value&gt;
                  &lt;description&gt;MapReduce JobHistory Server host:port. Default port is 10020.&lt;/description&gt;
          &lt;/property&gt;
          &lt;property&gt;
                  &lt;name&gt;mapreduce.jobhistory.webapp.address&lt;/name&gt;
                  &lt;value&gt;master:19888&lt;/value&gt;
                  &lt;description&gt;MapReduce JobHistory Server Web UI host:port. Default port is 19888.&lt;/description&gt;
          &lt;/property&gt;
          &lt;property&gt;
                  &lt;name&gt;mapreduce.jobhistory.intermediate-done-dir&lt;/name&gt;
                  &lt;value&gt;/mr-history/tmp&lt;/value&gt;
                  &lt;description&gt;Directory where history files are written by MapReduce jobs.&lt;/description&gt;
          &lt;/property&gt;
          &lt;property&gt;
                  &lt;name&gt;mapreduce.jobhistory.done-dir&lt;/name&gt;
                  &lt;value&gt;/mr-history/done&lt;/value&gt;
                  &lt;description&gt;Directory where history files are managed by the MR JobHistory Server.&lt;/description&gt;
          &lt;/property&gt;
  &lt;/configuration&gt;
  </code></pre>
  
  <p>yarn-site.xml</p>
  
  <pre><code>&lt;configuration&gt;
  
  &lt;!-- Site specific YARN configuration properties --&gt;
  &lt;!-- Configurations for ResourceManager and NodeManager --&gt;
          &lt;property&gt;
                  &lt;name&gt;yarn.acl.enable&lt;/name&gt;
                  &lt;value&gt;yes&lt;/value&gt;
                  &lt;description&gt;Enable ACLs? Defaults to false.&lt;/description&gt;
          &lt;/property&gt;
          &lt;property&gt;
                  &lt;name&gt;yarn.admin.acl&lt;/name&gt;
                  &lt;value&gt;false&lt;/value&gt;
                  &lt;description&gt;ACL to set admins on the cluster. ACLs are of for comma-separated-usersspacecomma-separated-groups. Defaults to special value of * which means anyone. Special value of just space means no one has access.&lt;/description&gt;
          &lt;/property&gt;
          &lt;property&gt;
                  &lt;name&gt;yarn.log-aggregation-enable&lt;/name&gt;
                  &lt;value&gt;false&lt;/value&gt;
                  &lt;description&gt;Configuration to enable or disable log aggregation&lt;/description&gt;
          &lt;/property&gt;
  &lt;!-- Configurations for ResourceManager --&gt;     
          &lt;property&gt;
                  &lt;name&gt;yarn.resourcemanager.address&lt;/name&gt;
                  &lt;value&gt;master:8050&lt;/value&gt;
                  &lt;description&gt;Value: host:port. If set, overrides the hostname set in yarn.resourcemanager.hostname.&lt;/description&gt;
          &lt;/property&gt;
          &lt;property&gt;
                  &lt;name&gt;yarn.resourcemanager.scheduler.address&lt;/name&gt;
                  &lt;value&gt;master:8030&lt;/value&gt;
                  &lt;description&gt;ResourceManager host:port for ApplicationMasters to talk to Scheduler to obtain resources. If set, overrides the hostname set in yarn.resourcemanager.hostname.&lt;/description&gt;
          &lt;/property&gt;
          &lt;property&gt;
                  &lt;name&gt;yarn.resourcemanager.resource-tracker.address&lt;/name&gt;
                  &lt;value&gt;master:8025&lt;/value&gt;
                  &lt;description&gt;ResourceManager host:port for NodeManagers. If set, overrides the hostname set in yarn.resourcemanager.hostname.&lt;/description&gt;
          &lt;/property&gt;
          &lt;property&gt;
                  &lt;name&gt;yarn.resourcemanager.admin.address&lt;/name&gt;
                  &lt;value&gt;master:8141&lt;/value&gt;
                  &lt;description&gt;ResourceManager host:port for administrative commands. If set, overrides the hostname set in yarn.resourcemanager.hostname.&lt;/description&gt;
          &lt;/property&gt;
          &lt;property&gt;
                  &lt;name&gt;yarn.resourcemanager.webapp.address&lt;/name&gt;
                  &lt;value&gt;master:8088&lt;/value&gt;
                  &lt;description&gt;web-ui host:port. If set, overrides the hostname set in&lt;/description&gt;
          &lt;/property&gt;             
          &lt;property&gt;
                  &lt;name&gt;yarn.resourcemanager.hostname&lt;/name&gt;
                  &lt;value&gt;master&lt;/value&gt;
                  &lt;description&gt;ResourceManager host&lt;/description&gt;
          &lt;/property&gt;
          &lt;property&gt;
                  &lt;name&gt;yarn.resourcemanager.scheduler.class&lt;/name&gt;
                  &lt;value&gt;org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler&lt;/value&gt;
                  &lt;description&gt;ResourceManager Scheduler class.&lt;/description&gt;
          &lt;/property&gt;
          &lt;property&gt;
              &lt;name&gt;yarn.scheduler.maximum-allocation-mb&lt;/name&gt;
              &lt;value&gt;6144&lt;/value&gt;
              &lt;description&gt;Maximum limit of memory to allocate to each container request at the Resource Manager. In MBs&lt;/description&gt;
          &lt;/property&gt; 
  
          &lt;property&gt;
              &lt;name&gt;yarn.scheduler.minimum-allocation-mb&lt;/name&gt;
              &lt;value&gt;2048&lt;/value&gt;
              &lt;description&gt;Minimum limit of memory to allocate to each container request at the Resource Manager. In MBs&lt;/description&gt;
          &lt;/property&gt; 
          &lt;property&gt;
                  &lt;name&gt;yarn.resourcemanager.nodes.include-path&lt;/name&gt;
                  &lt;value&gt;/opt/current/hadoop/etc/hadoop/slaves&lt;/value&gt;
                  &lt;description&gt;List of permitted NodeManagers. If necessary, use these files to control the list of allowable NodeManagers.&lt;/description&gt;
          &lt;/property&gt;
          &lt;property&gt;
                  &lt;name&gt;yarn.resourcemanager.nodes.exclude-path&lt;/name&gt;
                  &lt;value&gt;/opt/current/hadoop/etc/hadoop/excludes&lt;/value&gt;
                  &lt;description&gt;List of excluded NodeManagers. If necessary, use these files to control the list of allowable NodeManagers.&lt;/description&gt;
          &lt;/property&gt;
  &lt;!-- Configurations for NodeManager --&gt;
          &lt;property&gt;
                  &lt;name&gt;yarn.nodemanager.resource.memory-mb&lt;/name&gt;
                  &lt;value&gt;2048&lt;/value&gt;
                  &lt;description&gt;Resource i.e. available physical memory, in MB, for given NodeManager. Defines total available resources on the NodeManager to be made available to running containers&lt;/description&gt;
          &lt;/property&gt;
          &lt;property&gt;
              &lt;name&gt;yarn.nodemanager.vmem-pmem-ratio&lt;/name&gt;
              &lt;value&gt;2.1&lt;/value&gt;
              &lt;description&gt;Maximum ratio by which virtual memory usage of tasks may exceed physical memory. The virtual memory usage of each task may exceed its physical memory limit by this ratio. The total amount of virtual memory used by tasks on the NodeManager may exceed its physical memory usage by this ratio.&lt;/description&gt;
          &lt;/property&gt;
          &lt;property&gt;
                  &lt;name&gt;yarn.nodemanager.local-dirs&lt;/name&gt;
                  &lt;value&gt;/grid/hadoop1/yarn/local&lt;/value&gt;
                  &lt;description&gt;Comma-separated list of paths on the local filesystem where intermediate data is written.Multiple paths help spread disk i/o.&lt;/description&gt;
          &lt;/property&gt;    
          &lt;property&gt;
              &lt;name&gt;yarn.nodemanager.log-dirs&lt;/name&gt;
              &lt;value&gt;/var/log/hadoop-yarn/containers&lt;/value&gt;
              &lt;description&gt;Where to store container logs.&lt;/description&gt;
          &lt;/property&gt; 
          &lt;property&gt;
              &lt;name&gt;yarn.nodemanager.log.retain-second&lt;/name&gt;
              &lt;value&gt;10800&lt;/value&gt;
              &lt;description&gt;Default time (in seconds) to retain log files on the NodeManager Only applicable if log-aggregation is disabled.&lt;/description&gt;
          &lt;/property&gt;     
          &lt;property&gt;
              &lt;name&gt;yarn.nodemanager.remote-app-log-dir&lt;/name&gt;
              &lt;value&gt;/logs&lt;/value&gt;
              &lt;description&gt;HDFS directory where the application logs are moved on application completion. Need to set appropriate permissions. Only applicable if log-aggregation is enabled.&lt;/description&gt;
          &lt;/property&gt; 
          &lt;property&gt;
              &lt;name&gt;yarn.nodemanager.remote-app-log-dir-suffix&lt;/name&gt;
              &lt;value&gt;logs&lt;/value&gt;
              &lt;description&gt;Suffix appended to the remote log dir. Logs will be aggregated to ${yarn.nodemanager.remote-app-log-dir}/${user}/${thisParam} Only applicable if log-aggregation is enabled.&lt;/description&gt;
          &lt;/property&gt;
          &lt;property&gt;
              &lt;name&gt;yarn.nodemanager.aux-services&lt;/name&gt;
              &lt;value&gt;mapreduce_shuffle&lt;/value&gt;
              &lt;description&gt;Shuffle service that needs to be set for Map Reduce applications.&lt;/description&gt;
          &lt;/property&gt;
  
  &lt;/configuration&gt;
  </code></pre>
  
  <p>And finally /etc/hosts:</p>
  
  <pre><code>127.0.0.1 localhost
  
  ## BigData Hadoop Lab ##
  #Name Node
  172.25.28.100 master.hadoop.ot.ru master
  172.25.28.101 secondary.hadoop.ot.ru secondary
  #DataNodes on DL Servers
  172.25.28.102 slave102.hadoop.ot.ru slave102
  172.25.28.103 slave103.hadoop.ot.ru slave103
  172.25.28.104 slave104.hadoop.ot.ru slave104
  172.25.28.105 slave105.hadoop.ot.ru slave105
  172.25.28.106 slave106.hadoop.ot.ru slave106
  172.25.28.107 slave107.hadoop.ot.ru slave107
  #DataNodes on ARM Servers
  172.25.40.25 slave25.hadoop.ot.ru slave25
  172.25.40.26 slave26.hadoop.ot.ru slave26
  172.25.40.27 slave27.hadoop.ot.ru slave27
  172.25.40.28 slave28.hadoop.ot.ru slave28
  </code></pre>