hadoop/hadoop-common-project/hadoop-common/src/site/apt/ClusterSetup.apt.vm

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  ---
  Hadoop Map Reduce Next Generation-${project.version} - Cluster Setup
  ---
  ---
  ${maven.build.timestamp}

Hadoop MapReduce Next Generation - Cluster Setup

  \[ {{{./index.html}Go Back}} \]

%{toc|section=1|fromDepth=0}

* {Purpose}

  This document describes how to install, configure and manage non-trivial 
  Hadoop clusters ranging from a few nodes to extremely large clusters 
  with thousands of nodes.

  To play with Hadoop, you may first want to install it on a single 
  machine (see {{{SingleCluster}Single Node Setup}}).
  
* {Prerequisites}

  Download a stable version of Hadoop from Apache mirrors.
  
* {Installation}

  Installing a Hadoop cluster typically involves unpacking the software on all 
  the machines in the cluster or installing RPMs.

  Typically one machine in the cluster is designated as the NameNode and 
  another machine the as ResourceManager, exclusively. These are the masters. 
  
  The rest of the machines in the cluster act as both DataNode and NodeManager. 
  These are the slaves.

* {Running Hadoop in Non-Secure Mode}

  The following sections describe how to configure a Hadoop cluster.

  * {Configuration Files}
  
    Hadoop configuration is driven by two types of important configuration files:

      * Read-only default configuration - <<<core-default.xml>>>, 
        <<<hdfs-default.xml>>>, <<<yarn-default.xml>>> and 
        <<<mapred-default.xml>>>.
        
      * Site-specific configuration - <<conf/core-site.xml>>, 
        <<conf/hdfs-site.xml>>, <<conf/yarn-site.xml>> and 
        <<conf/mapred-site.xml>>.


    Additionally, you can control the Hadoop scripts found in the bin/ 
    directory of the distribution, by setting site-specific values via the 
    <<conf/hadoop-env.sh>> and <<yarn-env.sh>>.

  * {Site Configuration}
  
  To configure the Hadoop cluster you will need to configure the 
  <<<environment>>> in which the Hadoop daemons execute as well as the 
  <<<configuration parameters>>> for the Hadoop daemons.

  The Hadoop daemons are NameNode/DataNode and ResourceManager/NodeManager.


    * {Configuring Environment of Hadoop Daemons}
    
    Administrators should use the <<conf/hadoop-env.sh>> and 
    <<conf/yarn-env.sh>> script to do site-specific customization of the 
    Hadoop daemons' process environment.

    At the very least you should specify the <<<JAVA_HOME>>> so that it is 
    correctly defined on each remote node.

    In most cases you should also specify <<<HADOOP_PID_DIR>>> and 
    <<<HADOOP_SECURE_DN_PID_DIR>>> to point to directories that can only be
    written to by the users that are going to run the hadoop daemons.  
    Otherwise there is the potential for a symlink attack.

    Administrators can configure individual daemons using the configuration 
    options shown below in the table:

*--------------------------------------+--------------------------------------+
|| Daemon                              || Environment Variable                |
*--------------------------------------+--------------------------------------+
| NameNode                             | HADOOP_NAMENODE_OPTS                 |
*--------------------------------------+--------------------------------------+
| DataNode                             | HADOOP_DATANODE_OPTS                 |
*--------------------------------------+--------------------------------------+
| Secondary NameNode                   | HADOOP_SECONDARYNAMENODE_OPTS        |
*--------------------------------------+--------------------------------------+
| ResourceManager                      | YARN_RESOURCEMANAGER_OPTS            |
*--------------------------------------+--------------------------------------+
| NodeManager                          | YARN_NODEMANAGER_OPTS                |
*--------------------------------------+--------------------------------------+
| WebAppProxy                          | YARN_PROXYSERVER_OPTS                |
*--------------------------------------+--------------------------------------+
| Map Reduce Job History Server        | HADOOP_JOB_HISTORYSERVER_OPTS        |
*--------------------------------------+--------------------------------------+


    For example, To configure Namenode to use parallelGC, the following 
    statement should be added in hadoop-env.sh :
     
----
    export HADOOP_NAMENODE_OPTS="-XX:+UseParallelGC ${HADOOP_NAMENODE_OPTS}" 
----
    
    Other useful configuration parameters that you can customize include:

      * <<<HADOOP_LOG_DIR>>> / <<<YARN_LOG_DIR>>> - The directory where the 
        daemons' log files are stored. They are automatically created if they 
        don't exist.
        
      * <<<HADOOP_HEAPSIZE>>> / <<<YARN_HEAPSIZE>>> - The maximum amount of 
        heapsize to use, in MB e.g. if the varibale is set to 1000 the heap
        will be set to 1000MB.  This is used to configure the heap 
        size for the daemon. By default, the value is 1000.  If you want to
        configure the values separately for each deamon you can use.
*--------------------------------------+--------------------------------------+
|| Daemon                              || Environment Variable                |
*--------------------------------------+--------------------------------------+
| ResourceManager                      | YARN_RESOURCEMANAGER_HEAPSIZE        |
*--------------------------------------+--------------------------------------+
| NodeManager                          | YARN_NODEMANAGER_HEAPSIZE            |
*--------------------------------------+--------------------------------------+
| WebAppProxy                          | YARN_PROXYSERVER_HEAPSIZE            |
*--------------------------------------+--------------------------------------+
| Map Reduce Job History Server        | HADOOP_JOB_HISTORYSERVER_HEAPSIZE    |
*--------------------------------------+--------------------------------------+
 
    * {Configuring the Hadoop Daemons in Non-Secure Mode}

      This section deals with important parameters to be specified in 
      the given configuration files:
       
      * <<<conf/core-site.xml>>>
      
*-------------------------+-------------------------+------------------------+
|| Parameter              || Value                  || Notes                 |
*-------------------------+-------------------------+------------------------+
| <<<fs.defaultFS>>>      | NameNode URI            | <hdfs://host:port/>    |
*-------------------------+-------------------------+------------------------+
| <<<io.file.buffer.size>>> | 131072 |  |
| | | Size of read/write buffer used in SequenceFiles. |
*-------------------------+-------------------------+------------------------+

      * <<<conf/hdfs-site.xml>>>
      
        * Configurations for NameNode:

*-------------------------+-------------------------+------------------------+
|| Parameter              || Value                  || Notes                 |
*-------------------------+-------------------------+------------------------+
| <<<dfs.namenode.name.dir>>> | | | 
| | 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. |
*-------------------------+-------------------------+------------------------+
| <<<dfs.namenode.hosts>>> / <<<dfs.namenode.hosts.exclude>>> | | |
| | List of permitted/excluded DataNodes. | |
| | | If necessary, use these files to control the list of allowable |
| | | datanodes. |
*-------------------------+-------------------------+------------------------+
| <<<dfs.blocksize>>> | 268435456 | |
| | | HDFS blocksize of 256MB for large file-systems. |      
*-------------------------+-------------------------+------------------------+
| <<<dfs.namenode.handler.count>>> | 100 | |
| | | More NameNode server threads to handle RPCs from large number of |
| | | DataNodes. |
*-------------------------+-------------------------+------------------------+
        
        * Configurations for DataNode:
      
*-------------------------+-------------------------+------------------------+
|| Parameter              || Value                  || Notes                 |
*-------------------------+-------------------------+------------------------+
| <<<dfs.datanode.data.dir>>> | | |
| | 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. |
*-------------------------+-------------------------+------------------------+
      
      * <<<conf/yarn-site.xml>>>

        * Configurations for ResourceManager and NodeManager:

*-------------------------+-------------------------+------------------------+
|| Parameter              || Value                  || Notes                 |
*-------------------------+-------------------------+------------------------+
| <<<yarn.acl.enable>>> | | |
| | <<<true>>> / <<<false>>> | |
| | | Enable ACLs? Defaults to <false>. |
*-------------------------+-------------------------+------------------------+
| <<<yarn.admin.acl>>> | | |
| | Admin ACL | |
| | | ACL to set admins on the cluster. |
| | | ACLs are of for <comma-separated-users><space><comma-separated-groups>. |
| | | Defaults to special value of <<*>> which means <anyone>. |
| | | Special value of just <space> means no one has access. |
*-------------------------+-------------------------+------------------------+
| <<<yarn.log-aggregation-enable>>> | | |
| | <false> | |
| | | Configuration to enable or disable log aggregation |
*-------------------------+-------------------------+------------------------+


        * Configurations for ResourceManager:

*-------------------------+-------------------------+------------------------+
|| Parameter              || Value                  || Notes                 |
*-------------------------+-------------------------+------------------------+
| <<<yarn.resourcemanager.address>>> | | | 
| | <<<ResourceManager>>> host:port for clients to submit jobs. | |
| | | <host:port> |
*-------------------------+-------------------------+------------------------+
| <<<yarn.resourcemanager.scheduler.address>>> | | | 
| | <<<ResourceManager>>> host:port for ApplicationMasters to talk to | |
| | Scheduler to obtain resources. | |
| | | <host:port> |
*-------------------------+-------------------------+------------------------+
| <<<yarn.resourcemanager.resource-tracker.address>>> | | | 
| | <<<ResourceManager>>> host:port for NodeManagers. | |
| | | <host:port> |
*-------------------------+-------------------------+------------------------+
| <<<yarn.resourcemanager.admin.address>>> | | | 
| | <<<ResourceManager>>> host:port for administrative commands. | |
| | | <host:port> |
*-------------------------+-------------------------+------------------------+
| <<<yarn.resourcemanager.webapp.address>>> | | | 
| | <<<ResourceManager>>> web-ui host:port. | |
| | | <host:port> |
*-------------------------+-------------------------+------------------------+
| <<<yarn.resourcemanager.scheduler.class>>> | | |
| | <<<ResourceManager>>> Scheduler class. | |
| | | <<<CapacityScheduler>>> (recommended) or <<<FifoScheduler>>> |
*-------------------------+-------------------------+------------------------+
| <<<yarn.scheduler.minimum-allocation-mb>>> | | |
| | Minimum limit of memory to allocate to each container request at the <<<Resource Manager>>>. | |
| | | In MBs |
*-------------------------+-------------------------+------------------------+
| <<<yarn.scheduler.maximum-allocation-mb>>> | | |
| | Maximum limit of memory to allocate to each container request at the <<<Resource Manager>>>. | |
| | | In MBs |
*-------------------------+-------------------------+------------------------+
| <<<yarn.resourcemanager.nodes.include-path>>> / | | | 
| <<<yarn.resourcemanager.nodes.exclude-path>>> | | |  
| | List of permitted/excluded NodeManagers. | |
| | | If necessary, use these files to control the list of allowable | 
| | | NodeManagers. |
*-------------------------+-------------------------+------------------------+
 
        * Configurations for NodeManager:

*-------------------------+-------------------------+------------------------+
|| Parameter              || Value                  || Notes                 |
*-------------------------+-------------------------+------------------------+
| <<<yarn.nodemanager.resource.memory-mb>>> | | |
| | 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 |
*-------------------------+-------------------------+------------------------+
| <<<yarn.nodemanager.vmem-pmem-ratio>>> | | |
| | 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. |
*-------------------------+-------------------------+------------------------+
| <<<yarn.nodemanager.local-dirs>>> | | |
| | Comma-separated list of paths on the local filesystem where | |
| | intermediate data is written. ||
| | | Multiple paths help spread disk i/o. |
*-------------------------+-------------------------+------------------------+
| <<<yarn.nodemanager.log-dirs>>> | | |
| | Comma-separated list of paths on the local filesystem where logs  | |
| | are written. | |
| | | Multiple paths help spread disk i/o. |
*-------------------------+-------------------------+------------------------+
| <<<yarn.nodemanager.log.retain-seconds>>> | | |
| | <10800> | |
| | | Default time (in seconds) to retain log files on the NodeManager |
| | | Only applicable if log-aggregation is disabled. |
*-------------------------+-------------------------+------------------------+
| <<<yarn.nodemanager.remote-app-log-dir>>> | | |
| | </logs> | |
| | | HDFS directory where the application logs are moved on application |
| | | completion. Need to set appropriate permissions. |
| | | Only applicable if log-aggregation is enabled. |
*-------------------------+-------------------------+------------------------+
| <<<yarn.nodemanager.remote-app-log-dir-suffix>>> | | |
| | <logs> | |
| | | 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. |
*-------------------------+-------------------------+------------------------+
| <<<yarn.nodemanager.aux-services>>> | | |
| | mapreduce.shuffle  | |
| | | Shuffle service that needs to be set for Map Reduce applications. |
*-------------------------+-------------------------+------------------------+

        * Configurations for History Server (Needs to be moved elsewhere):

*-------------------------+-------------------------+------------------------+
|| Parameter              || Value                  || Notes                 |
*-------------------------+-------------------------+------------------------+
| <<<yarn.log-aggregation.retain-seconds>>> | | |
| | <-1> | |
| | | How long to keep aggregation logs before deleting them. -1 disables. |
| | | Be careful, set this too small and you will spam the name node. |
*-------------------------+-------------------------+------------------------+



      * <<<conf/mapred-site.xml>>>

        * Configurations for MapReduce Applications:

*-------------------------+-------------------------+------------------------+
|| Parameter              || Value                  || Notes                 |
*-------------------------+-------------------------+------------------------+
| <<<mapreduce.framework.name>>> | | |
| | yarn | |
| | | Execution framework set to Hadoop YARN. |
*-------------------------+-------------------------+------------------------+
| <<<mapreduce.map.memory.mb>>> | 1536 | |
| | | Larger resource limit for maps. |
*-------------------------+-------------------------+------------------------+
| <<<mapreduce.map.java.opts>>> | -Xmx1024M | |
| | | Larger heap-size for child jvms of maps. |
*-------------------------+-------------------------+------------------------+
| <<<mapreduce.reduce.memory.mb>>> | 3072 | |
| | | Larger resource limit for reduces. |
*-------------------------+-------------------------+------------------------+
| <<<mapreduce.reduce.java.opts>>> | -Xmx2560M | |
| | | Larger heap-size for child jvms of reduces. |
*-------------------------+-------------------------+------------------------+
| <<<mapreduce.task.io.sort.mb>>> | 512 | |
| | | Higher memory-limit while sorting data for efficiency. |
*-------------------------+-------------------------+------------------------+
| <<<mapreduce.task.io.sort.factor>>> | 100 | |
| | | More streams merged at once while sorting files. |
*-------------------------+-------------------------+------------------------+
| <<<mapreduce.reduce.shuffle.parallelcopies>>> | 50 | |
| | | Higher number of parallel copies run by reduces to fetch outputs |
| | | from very large number of maps. |
*-------------------------+-------------------------+------------------------+

        * Configurations for MapReduce JobHistory Server:

*-------------------------+-------------------------+------------------------+
|| Parameter              || Value                  || Notes                 |
*-------------------------+-------------------------+------------------------+
| <<<mapreduce.jobhistory.address>>> | | |
| | MapReduce JobHistory Server <host:port> | Default port is 10020. |
*-------------------------+-------------------------+------------------------+
| <<<mapreduce.jobhistory.webapp.address>>> | | |
| | MapReduce JobHistory Server Web UI <host:port> | Default port is 19888. |
*-------------------------+-------------------------+------------------------+
| <<<mapreduce.jobhistory.intermediate-done-dir>>> | /mr-history/tmp | |
|  | | Directory where history files are written by MapReduce jobs. | 
*-------------------------+-------------------------+------------------------+
| <<<mapreduce.jobhistory.done-dir>>> | /mr-history/done| |
| | | Directory where history files are managed by the MR JobHistory Server. | 
*-------------------------+-------------------------+------------------------+

      * Hadoop Rack Awareness
      
      The HDFS and the YARN components are rack-aware.

      The NameNode and the ResourceManager obtains the rack information of the 
      slaves in the cluster by invoking an API <resolve> in an administrator 
      configured module. 
      
      The API resolves the DNS name (also IP address) to a rack id. 
      
      The site-specific module to use can be configured using the configuration 
      item <<<topology.node.switch.mapping.impl>>>. The default implementation 
      of the same runs a script/command configured using 
      <<<topology.script.file.name>>>. If <<<topology.script.file.name>>> is 
      not set, the rack id </default-rack> is returned for any passed IP address. 

      * Monitoring Health of NodeManagers
      
      Hadoop provides a mechanism by which administrators can configure the 
      NodeManager to run an administrator supplied script periodically to 
      determine if a node is healthy or not. 
      
      Administrators can determine if the node is in a healthy state by 
      performing any checks of their choice in the script. If the script 
      detects the node to be in an unhealthy state, it must print a line to 
      standard output beginning with the string ERROR. The NodeManager spawns 
      the script periodically and checks its output. If the script's output 
      contains the string ERROR, as described above, the node's status is 
      reported as <<<unhealthy>>> and the node is black-listed by the 
      ResourceManager. No further tasks will be assigned to this node. 
      However, the NodeManager continues to run the script, so that if the 
      node becomes healthy again, it will be removed from the blacklisted nodes
      on the ResourceManager automatically. The node's health along with the 
      output of the script, if it is unhealthy, is available to the 
      administrator in the ResourceManager web interface. The time since the 
      node was healthy is also displayed on the web interface.

      The following parameters can be used to control the node health 
      monitoring script in <<<conf/yarn-site.xml>>>.

*-------------------------+-------------------------+------------------------+
|| Parameter              || Value                  || Notes                 |
*-------------------------+-------------------------+------------------------+
| <<<yarn.nodemanager.health-checker.script.path>>> | | |
| | Node health script  | |
| | | Script to check for node's health status. |
*-------------------------+-------------------------+------------------------+
| <<<yarn.nodemanager.health-checker.script.opts>>> | | |
| | Node health script options  | |
| | | Options for script to check for node's health status. |
*-------------------------+-------------------------+------------------------+
| <<<yarn.nodemanager.health-checker.script.interval-ms>>> | | |
| | Node health script interval  | |
| | | Time interval for running health script. |
*-------------------------+-------------------------+------------------------+
| <<<yarn.nodemanager.health-checker.script.timeout-ms>>> | | |
| | Node health script timeout interval  | |
| | | Timeout for health script execution. |
*-------------------------+-------------------------+------------------------+

    The health checker script is not supposed to give ERROR if only some of the
    local disks become bad. NodeManager has the ability to periodically check
    the health of the local disks (specifically checks nodemanager-local-dirs
    and nodemanager-log-dirs) and after reaching the threshold of number of
    bad directories based on the value set for the config property
    yarn.nodemanager.disk-health-checker.min-healthy-disks, the whole node is
    marked unhealthy and this info is sent to resource manager also. The boot
    disk is either raided or a failure in the boot disk is identified by the
    health checker script.

    * {Slaves file}
      
    Typically you choose one machine in the cluster to act as the NameNode and 
    one machine as to act as the ResourceManager, exclusively. The rest of the 
    machines act as both a DataNode and NodeManager and are referred to as 
    <slaves>.

    List all slave hostnames or IP addresses in your <<<conf/slaves>>> file, 
    one per line.

    * {Logging}
    
    Hadoop uses the Apache log4j via the Apache Commons Logging framework for 
    logging. Edit the <<<conf/log4j.properties>>> file to customize the 
    Hadoop daemons' logging configuration (log-formats and so on).
    
  * {Operating the Hadoop Cluster}

  Once all the necessary configuration is complete, distribute the files to the 
  <<<HADOOP_CONF_DIR>>> directory on all the machines.

    * Hadoop Startup
  
    To start a Hadoop cluster you will need to start both the HDFS and YARN 
    cluster.

    Format a new distributed filesystem:
  
----
  $ $HADOOP_PREFIX/bin/hdfs namenode -format <cluster_name>
----

    Start the HDFS with the following command, run on the designated NameNode:
  
----
  $ $HADOOP_PREFIX/sbin/hadoop-daemon.sh --config $HADOOP_CONF_DIR --script hdfs start namenode
----    	  

    Run a script to start DataNodes on all slaves:

----
  $ $HADOOP_PREFIX/sbin/hadoop-daemon.sh --config $HADOOP_CONF_DIR --script hdfs start datanode
----    	  
  
    Start the YARN with the following command, run on the designated 
    ResourceManager:
  
----
  $ $HADOOP_YARN_HOME/sbin/yarn-daemon.sh --config $HADOOP_CONF_DIR start resourcemanager 
----    	  

    Run a script to start NodeManagers on all slaves:

----
  $ $HADOOP_YARN_HOME/sbin/yarn-daemon.sh --config $HADOOP_CONF_DIR start nodemanager 
----    	  

    Start a standalone WebAppProxy server.  If multiple servers
    are used with load balancing it should be run on each of them:

----
  $ $HADOOP_YARN_HOME/bin/yarn start proxyserver --config $HADOOP_CONF_DIR  
----

    Start the MapReduce JobHistory Server with the following command, run on the  
    designated server:
  
----
  $ $HADOOP_PREFIX/sbin/mr-jobhistory-daemon.sh start historyserver --config $HADOOP_CONF_DIR  
----    	  

    * Hadoop Shutdown      

    Stop the NameNode with the following command, run on the designated 
    NameNode:
  
----
  $ $HADOOP_PREFIX/sbin/hadoop-daemon.sh --config $HADOOP_CONF_DIR --script hdfs stop namenode
----    	  

    Run a script to stop DataNodes on all slaves:

----
  $ $HADOOP_PREFIX/sbin/hadoop-daemon.sh --config $HADOOP_CONF_DIR --script hdfs stop datanode
----    	  
  
    Stop the ResourceManager with the following command, run on the designated 
    ResourceManager:
  
----
  $ $HADOOP_YARN_HOME/sbin/yarn-daemon.sh --config $HADOOP_CONF_DIR stop resourcemanager 
----    	  

    Run a script to stop NodeManagers on all slaves:

----
  $ $HADOOP_YARN_HOME/sbin/yarn-daemon.sh --config $HADOOP_CONF_DIR stop nodemanager 
----    	  

    Stop the WebAppProxy server. If multiple servers are used with load
    balancing it should be run on each of them:

----
  $ $HADOOP_YARN_HOME/bin/yarn stop proxyserver --config $HADOOP_CONF_DIR  
----


    Stop the MapReduce JobHistory Server with the following command, run on the  
    designated server:
  
----
  $ $HADOOP_PREFIX/sbin/mr-jobhistory-daemon.sh stop historyserver --config $HADOOP_CONF_DIR  
----    	  

    
* {Running Hadoop in Secure Mode}

  This section deals with important parameters to be specified in 
  to run Hadoop in <<secure mode>> with strong, Kerberos-based
  authentication.
      
  * <<<User Accounts for Hadoop Daemons>>>
      
  Ensure that HDFS and YARN daemons run as different Unix users, for e.g.
  <<<hdfs>>> and <<<yarn>>>. Also, ensure that the MapReduce JobHistory
  server runs as user <<<mapred>>>. 
      
  It's recommended to have them share a Unix group, for e.g. <<<hadoop>>>.
      
*--------------------------------------+----------------------------------------------------------------------+
|| User:Group                          || Daemons                                                             |
*--------------------------------------+----------------------------------------------------------------------+
| hdfs:hadoop                          | NameNode, Secondary NameNode, Checkpoint Node, Backup Node, DataNode |
*--------------------------------------+----------------------------------------------------------------------+
| yarn:hadoop                          | ResourceManager, NodeManager                                         |
*--------------------------------------+----------------------------------------------------------------------+
| mapred:hadoop                        | MapReduce JobHistory Server                                          |
*--------------------------------------+----------------------------------------------------------------------+
      
  * <<<Permissions for both HDFS and local fileSystem paths>>>
     
  The following table lists various paths on HDFS and local filesystems (on
  all nodes) and recommended permissions:
   
*-------------------+-------------------+------------------+------------------+
|| Filesystem       || Path             || User:Group      || Permissions     |
*-------------------+-------------------+------------------+------------------+
| local | <<<dfs.namenode.name.dir>>> | hdfs:hadoop | drwx------ | 
*-------------------+-------------------+------------------+------------------+
| local | <<<dfs.datanode.data.dir>>> | hdfs:hadoop | drwx------ |
*-------------------+-------------------+------------------+------------------+
| local | $HADOOP_LOG_DIR | hdfs:hadoop | drwxrwxr-x |
*-------------------+-------------------+------------------+------------------+
| local | $YARN_LOG_DIR | yarn:hadoop | drwxrwxr-x |
*-------------------+-------------------+------------------+------------------+
| local | <<<yarn.nodemanager.local-dirs>>> | yarn:hadoop | drwxr-xr-x |
*-------------------+-------------------+------------------+------------------+
| local | <<<yarn.nodemanager.log-dirs>>> | yarn:hadoop | drwxr-xr-x |
*-------------------+-------------------+------------------+------------------+
| local | container-executor | root:hadoop | --Sr-s--- |
*-------------------+-------------------+------------------+------------------+
| local | <<<conf/container-executor.cfg>>> | root:hadoop | r-------- |
*-------------------+-------------------+------------------+------------------+
| hdfs | / | hdfs:hadoop | drwxr-xr-x |
*-------------------+-------------------+------------------+------------------+
| hdfs | /tmp | hdfs:hadoop | drwxrwxrwxt |
*-------------------+-------------------+------------------+------------------+
| hdfs | /user | hdfs:hadoop | drwxr-xr-x |
*-------------------+-------------------+------------------+------------------+
| hdfs | <<<yarn.nodemanager.remote-app-log-dir>>> | yarn:hadoop | drwxrwxrwxt |
*-------------------+-------------------+------------------+------------------+
| hdfs | <<<mapreduce.jobhistory.intermediate-done-dir>>> | mapred:hadoop | |
| | | | drwxrwxrwxt |      
*-------------------+-------------------+------------------+------------------+
| hdfs | <<<mapreduce.jobhistory.done-dir>>> | mapred:hadoop | |
| | | | drwxr-x--- |      
*-------------------+-------------------+------------------+------------------+

  * Kerberos Keytab files
  
    * HDFS
    
    The NameNode keytab file, on the NameNode host, should look like the 
    following:
    
----

$ /usr/kerberos/bin/klist -e -k -t /etc/security/keytab/nn.service.keytab 
Keytab name: FILE:/etc/security/keytab/nn.service.keytab
KVNO Timestamp         Principal
   4 07/18/11 21:08:09 nn/full.qualified.domain.name@REALM.TLD (AES-256 CTS mode with 96-bit SHA-1 HMAC) 
   4 07/18/11 21:08:09 nn/full.qualified.domain.name@REALM.TLD (AES-128 CTS mode with 96-bit SHA-1 HMAC) 
   4 07/18/11 21:08:09 nn/full.qualified.domain.name@REALM.TLD (ArcFour with HMAC/md5) 
   4 07/18/11 21:08:09 host/full.qualified.domain.name@REALM.TLD (AES-256 CTS mode with 96-bit SHA-1 HMAC) 
   4 07/18/11 21:08:09 host/full.qualified.domain.name@REALM.TLD (AES-128 CTS mode with 96-bit SHA-1 HMAC) 
   4 07/18/11 21:08:09 host/full.qualified.domain.name@REALM.TLD (ArcFour with HMAC/md5) 

----

    The Secondary NameNode keytab file, on that host, should look like the 
    following:
    
----

$ /usr/kerberos/bin/klist -e -k -t /etc/security/keytab/sn.service.keytab 
Keytab name: FILE:/etc/security/keytab/sn.service.keytab
KVNO Timestamp         Principal
   4 07/18/11 21:08:09 sn/full.qualified.domain.name@REALM.TLD (AES-256 CTS mode with 96-bit SHA-1 HMAC) 
   4 07/18/11 21:08:09 sn/full.qualified.domain.name@REALM.TLD (AES-128 CTS mode with 96-bit SHA-1 HMAC) 
   4 07/18/11 21:08:09 sn/full.qualified.domain.name@REALM.TLD (ArcFour with HMAC/md5) 
   4 07/18/11 21:08:09 host/full.qualified.domain.name@REALM.TLD (AES-256 CTS mode with 96-bit SHA-1 HMAC) 
   4 07/18/11 21:08:09 host/full.qualified.domain.name@REALM.TLD (AES-128 CTS mode with 96-bit SHA-1 HMAC) 
   4 07/18/11 21:08:09 host/full.qualified.domain.name@REALM.TLD (ArcFour with HMAC/md5) 

----

    The DataNode keytab file, on each host, should look like the following:
    
----

$ /usr/kerberos/bin/klist -e -k -t /etc/security/keytab/dn.service.keytab 
Keytab name: FILE:/etc/security/keytab/dn.service.keytab
KVNO Timestamp         Principal
   4 07/18/11 21:08:09 dn/full.qualified.domain.name@REALM.TLD (AES-256 CTS mode with 96-bit SHA-1 HMAC) 
   4 07/18/11 21:08:09 dn/full.qualified.domain.name@REALM.TLD (AES-128 CTS mode with 96-bit SHA-1 HMAC) 
   4 07/18/11 21:08:09 dn/full.qualified.domain.name@REALM.TLD (ArcFour with HMAC/md5) 
   4 07/18/11 21:08:09 host/full.qualified.domain.name@REALM.TLD (AES-256 CTS mode with 96-bit SHA-1 HMAC) 
   4 07/18/11 21:08:09 host/full.qualified.domain.name@REALM.TLD (AES-128 CTS mode with 96-bit SHA-1 HMAC) 
   4 07/18/11 21:08:09 host/full.qualified.domain.name@REALM.TLD (ArcFour with HMAC/md5) 

----
    
    * YARN
    
    The ResourceManager keytab file, on the ResourceManager host, should look  
    like the following:
    
----

$ /usr/kerberos/bin/klist -e -k -t /etc/security/keytab/rm.service.keytab 
Keytab name: FILE:/etc/security/keytab/rm.service.keytab
KVNO Timestamp         Principal
   4 07/18/11 21:08:09 rm/full.qualified.domain.name@REALM.TLD (AES-256 CTS mode with 96-bit SHA-1 HMAC) 
   4 07/18/11 21:08:09 rm/full.qualified.domain.name@REALM.TLD (AES-128 CTS mode with 96-bit SHA-1 HMAC) 
   4 07/18/11 21:08:09 rm/full.qualified.domain.name@REALM.TLD (ArcFour with HMAC/md5) 
   4 07/18/11 21:08:09 host/full.qualified.domain.name@REALM.TLD (AES-256 CTS mode with 96-bit SHA-1 HMAC) 
   4 07/18/11 21:08:09 host/full.qualified.domain.name@REALM.TLD (AES-128 CTS mode with 96-bit SHA-1 HMAC) 
   4 07/18/11 21:08:09 host/full.qualified.domain.name@REALM.TLD (ArcFour with HMAC/md5) 

----

    The NodeManager keytab file, on each host, should look like the following:
    
----

$ /usr/kerberos/bin/klist -e -k -t /etc/security/keytab/nm.service.keytab 
Keytab name: FILE:/etc/security/keytab/nm.service.keytab
KVNO Timestamp         Principal
   4 07/18/11 21:08:09 nm/full.qualified.domain.name@REALM.TLD (AES-256 CTS mode with 96-bit SHA-1 HMAC) 
   4 07/18/11 21:08:09 nm/full.qualified.domain.name@REALM.TLD (AES-128 CTS mode with 96-bit SHA-1 HMAC) 
   4 07/18/11 21:08:09 nm/full.qualified.domain.name@REALM.TLD (ArcFour with HMAC/md5) 
   4 07/18/11 21:08:09 host/full.qualified.domain.name@REALM.TLD (AES-256 CTS mode with 96-bit SHA-1 HMAC) 
   4 07/18/11 21:08:09 host/full.qualified.domain.name@REALM.TLD (AES-128 CTS mode with 96-bit SHA-1 HMAC) 
   4 07/18/11 21:08:09 host/full.qualified.domain.name@REALM.TLD (ArcFour with HMAC/md5) 

----
    
    * MapReduce JobHistory Server

    The MapReduce JobHistory Server keytab file, on that host, should look  
    like the following:
    
----

$ /usr/kerberos/bin/klist -e -k -t /etc/security/keytab/jhs.service.keytab 
Keytab name: FILE:/etc/security/keytab/jhs.service.keytab
KVNO Timestamp         Principal
   4 07/18/11 21:08:09 jhs/full.qualified.domain.name@REALM.TLD (AES-256 CTS mode with 96-bit SHA-1 HMAC) 
   4 07/18/11 21:08:09 jhs/full.qualified.domain.name@REALM.TLD (AES-128 CTS mode with 96-bit SHA-1 HMAC) 
   4 07/18/11 21:08:09 jhs/full.qualified.domain.name@REALM.TLD (ArcFour with HMAC/md5) 
   4 07/18/11 21:08:09 host/full.qualified.domain.name@REALM.TLD (AES-256 CTS mode with 96-bit SHA-1 HMAC) 
   4 07/18/11 21:08:09 host/full.qualified.domain.name@REALM.TLD (AES-128 CTS mode with 96-bit SHA-1 HMAC) 
   4 07/18/11 21:08:09 host/full.qualified.domain.name@REALM.TLD (ArcFour with HMAC/md5) 

----
    
  * Configuration in Secure Mode
  
    * <<<conf/core-site.xml>>>

*-------------------------+-------------------------+------------------------+
|| Parameter              || Value                  || Notes                 |
*-------------------------+-------------------------+------------------------+
| <<<hadoop.security.authentication>>> | <kerberos> | <simple> is non-secure. |
*-------------------------+-------------------------+------------------------+
| <<<hadoop.security.authorization>>> | <true> | |
| | | Enable RPC service-level authorization. |
*-------------------------+-------------------------+------------------------+

    * <<<conf/hdfs-site.xml>>>
    
      * Configurations for NameNode:
    
*-------------------------+-------------------------+------------------------+
|| Parameter              || Value                  || Notes                 |
*-------------------------+-------------------------+------------------------+
| <<<dfs.block.access.token.enable>>> | <true> |  |
| | | Enable HDFS block access tokens for secure operations. |
*-------------------------+-------------------------+------------------------+
| <<<dfs.https.enable>>> | <true> | |
*-------------------------+-------------------------+------------------------+
| <<<dfs.namenode.https-address>>> | <nn_host_fqdn:50470> | |
*-------------------------+-------------------------+------------------------+
| <<<dfs.https.port>>> | <50470> | |
*-------------------------+-------------------------+------------------------+
| <<<dfs.namenode.keytab.file>>> | </etc/security/keytab/nn.service.keytab> | |
| | | Kerberos keytab file for the NameNode. |
*-------------------------+-------------------------+------------------------+
| <<<dfs.namenode.kerberos.principal>>> | nn/_HOST@REALM.TLD | |
| | | Kerberos principal name for the NameNode. |
*-------------------------+-------------------------+------------------------+
| <<<dfs.namenode.kerberos.https.principal>>> | host/_HOST@REALM.TLD | |
| | | HTTPS Kerberos principal name for the NameNode. |
*-------------------------+-------------------------+------------------------+

      * Configurations for Secondary NameNode:
    
*-------------------------+-------------------------+------------------------+
|| Parameter              || Value                  || Notes                 |
*-------------------------+-------------------------+------------------------+
| <<<dfs.namenode.secondary.http-address>>> | <c_nn_host_fqdn:50090> | |
*-------------------------+-------------------------+------------------------+
| <<<dfs.namenode.secondary.https-port>>> | <50470> | |
*-------------------------+-------------------------+------------------------+
| <<<dfs.namenode.secondary.keytab.file>>> | | | 
| | </etc/security/keytab/sn.service.keytab> | |
| | | Kerberos keytab file for the NameNode. |
*-------------------------+-------------------------+------------------------+
| <<<dfs.namenode.secondary.kerberos.principal>>> | sn/_HOST@REALM.TLD | |
| | | Kerberos principal name for the Secondary NameNode. |
*-------------------------+-------------------------+------------------------+
| <<<dfs.namenode.secondary.kerberos.https.principal>>> | | |
| | host/_HOST@REALM.TLD | |
| | | HTTPS Kerberos principal name for the Secondary NameNode. |
*-------------------------+-------------------------+------------------------+

      * Configurations for DataNode:

*-------------------------+-------------------------+------------------------+
|| Parameter              || Value                  || Notes                 |
*-------------------------+-------------------------+------------------------+
| <<<dfs.datanode.data.dir.perm>>> | 700 | |
*-------------------------+-------------------------+------------------------+
| <<<dfs.datanode.address>>> | <0.0.0.0:2003> | |
*-------------------------+-------------------------+------------------------+
| <<<dfs.datanode.https.address>>> | <0.0.0.0:2005> | |
*-------------------------+-------------------------+------------------------+
| <<<dfs.datanode.keytab.file>>> | </etc/security/keytab/dn.service.keytab> | |
| | | Kerberos keytab file for the DataNode. |
*-------------------------+-------------------------+------------------------+
| <<<dfs.datanode.kerberos.principal>>> | dn/_HOST@REALM.TLD | |
| | | Kerberos principal name for the DataNode. |
*-------------------------+-------------------------+------------------------+
| <<<dfs.datanode.kerberos.https.principal>>> | | |
| | host/_HOST@REALM.TLD | |
| | | HTTPS Kerberos principal name for the DataNode. |
*-------------------------+-------------------------+------------------------+

    * <<<conf/yarn-site.xml>>>
    
      * WebAppProxy

      The <<<WebAppProxy>>> provides a proxy between the web applications
      exported by an application and an end user.  If security is enabled
      it will warn users before accessing a potentially unsafe web application.
      Authentication and authorization using the proxy is handled just like
      any other privileged web application.

*-------------------------+-------------------------+------------------------+
|| Parameter              || Value                  || Notes                 |
*-------------------------+-------------------------+------------------------+
| <<<yarn.web-proxy.address>>> | | |
| | <<<WebAppProxy>>> host:port for proxy to AM web apps. | |
| | | <host:port> if this is the same as <<<yarn.resourcemanager.webapp.address>>>|
| | | or it is not defined then the <<<ResourceManager>>> will run the proxy|
| | | otherwise a standalone proxy server will need to be launched.|
*-------------------------+-------------------------+------------------------+
| <<<yarn.web-proxy.keytab>>> | | |
| | </etc/security/keytab/web-app.service.keytab> | |
| | | Kerberos keytab file for the WebAppProxy. |
*-------------------------+-------------------------+------------------------+
| <<<yarn.web-proxy.principal>>> | wap/_HOST@REALM.TLD | |
| | | Kerberos principal name for the WebAppProxy. |
*-------------------------+-------------------------+------------------------+

      * LinuxContainerExecutor
      
      A <<<ContainerExecutor>>> used by YARN framework which define how any
      <container> launched and controlled. 
      
      The following are the available in Hadoop YARN:

*--------------------------------------+--------------------------------------+
|| ContainerExecutor                   || Description                         |
*--------------------------------------+--------------------------------------+
| <<<DefaultContainerExecutor>>>             | |
| | The default executor which YARN uses to manage container execution. |
| | The container process has the same Unix user as the NodeManager.  |
*--------------------------------------+--------------------------------------+
| <<<LinuxContainerExecutor>>>               | |
| | Supported only on GNU/Linux, this executor runs the containers as the | 
| | user who submitted the application. It requires all user accounts to be |
| | created on the cluster nodes where the containers are launched. It uses |
| | a <setuid> executable that is included in the Hadoop distribution. |
| | The NodeManager uses this executable to launch and kill containers. |
| | The setuid executable switches to the user who has submitted the |
| | application and launches or kills the containers. For maximum security, |
| | this executor sets up restricted permissions and user/group ownership of |
| | local files and directories used by the containers such as the shared |
| | objects, jars, intermediate files, log files etc. Particularly note that, |
| | because of this, except the application owner and NodeManager, no other |
| | user can access any of the local files/directories including those |
| | localized as part of the distributed cache. |
*--------------------------------------+--------------------------------------+

      To build the LinuxContainerExecutor executable run:
        
----
 $ mvn package -Dcontainer-executor.conf.dir=/etc/hadoop/
----
        
      The path passed in <<<-Dcontainer-executor.conf.dir>>> should be the 
      path on the cluster nodes where a configuration file for the setuid 
      executable should be located. The executable should be installed in
      $HADOOP_YARN_HOME/bin.

      The executable must have specific permissions: 6050 or --Sr-s--- 
      permissions user-owned by <root> (super-user) and group-owned by a 
      special group (e.g. <<<hadoop>>>) of which the NodeManager Unix user is 
      the group member and no ordinary application user is. If any application 
      user belongs to this special group, security will be compromised. This 
      special group name should be specified for the configuration property 
      <<<yarn.nodemanager.linux-container-executor.group>>> in both 
      <<<conf/yarn-site.xml>>> and <<<conf/container-executor.cfg>>>. 
      
      For example, let's say that the NodeManager is run as user <yarn> who is 
      part of the groups users and <hadoop>, any of them being the primary group.
      Let also be that <users> has both <yarn> and another user 
      (application submitter) <alice> as its members, and <alice> does not 
      belong to <hadoop>. Going by the above description, the setuid/setgid 
      executable should be set 6050 or --Sr-s--- with user-owner as <yarn> and 
      group-owner as <hadoop> which has <yarn> as its member (and not <users> 
      which has <alice> also as its member besides <yarn>).

      The LinuxTaskController requires that paths including and leading up to 
      the directories specified in <<<yarn.nodemanager.local-dirs>>> and 
      <<<yarn.nodemanager.log-dirs>>> to be set 755 permissions as described 
      above in the table on permissions on directories.

        * <<<conf/container-executor.cfg>>>
        
        The executable requires a configuration file called 
        <<<container-executor.cfg>>> to be present in the configuration 
        directory passed to the mvn target mentioned above. 

        The configuration file must be owned by the user running NodeManager 
        (user <<<yarn>>> in the above example), group-owned by anyone and 
        should have the permissions 0400 or r--------.

        The executable requires following configuration items to be present 
        in the <<<conf/container-executor.cfg>>> file. The items should be 
        mentioned as simple key=value pairs, one per-line:

*-------------------------+-------------------------+------------------------+
|| Parameter              || Value                  || Notes                 |
*-------------------------+-------------------------+------------------------+
| <<<yarn.nodemanager.linux-container-executor.group>>> | <hadoop> | |
| | | Unix group of the NodeManager. The group owner of the |
| | |<container-executor> binary should be this group. Should be same as the |
| | | value with which the NodeManager is configured. This configuration is |
| | | required for validating the secure access of the <container-executor> |
| | | binary. |        
*-------------------------+-------------------------+------------------------+
| <<<banned.users>>> | hfds,yarn,mapred,bin | Banned users. |
*-------------------------+-------------------------+------------------------+
| <<<min.user.id>>> | 1000 | Prevent other super-users. |      
*-------------------------+-------------------------+------------------------+

      To re-cap, here are the local file-ssytem permissions required for the 
      various paths related to the <<<LinuxContainerExecutor>>>:
      
*-------------------+-------------------+------------------+------------------+
|| Filesystem       || Path             || User:Group      || Permissions     |
*-------------------+-------------------+------------------+------------------+
| local | container-executor | root:hadoop | --Sr-s--- |
*-------------------+-------------------+------------------+------------------+
| local | <<<conf/container-executor.cfg>>> | root:hadoop | r-------- |
*-------------------+-------------------+------------------+------------------+
| local | <<<yarn.nodemanager.local-dirs>>> | yarn:hadoop | drwxr-xr-x |
*-------------------+-------------------+------------------+------------------+
| local | <<<yarn.nodemanager.log-dirs>>> | yarn:hadoop | drwxr-xr-x |
*-------------------+-------------------+------------------+------------------+
      
      * Configurations for ResourceManager:
    
*-------------------------+-------------------------+------------------------+
|| Parameter              || Value                  || Notes                 |
*-------------------------+-------------------------+------------------------+
| <<<yarn.resourcemanager.keytab>>> | | |
| | </etc/security/keytab/rm.service.keytab> | |
| | | Kerberos keytab file for the ResourceManager. |
*-------------------------+-------------------------+------------------------+
| <<<yarn.resourcemanager.principal>>> | rm/_HOST@REALM.TLD | |
| | | Kerberos principal name for the ResourceManager. |
*-------------------------+-------------------------+------------------------+
      
      * Configurations for NodeManager:
      
*-------------------------+-------------------------+------------------------+
|| Parameter              || Value                  || Notes                 |
*-------------------------+-------------------------+------------------------+
| <<<yarn.nodemanager.keytab>>> | </etc/security/keytab/nm.service.keytab> | |
| | | Kerberos keytab file for the NodeManager. |
*-------------------------+-------------------------+------------------------+
| <<<yarn.nodemanager.principal>>> | nm/_HOST@REALM.TLD | |
| | | Kerberos principal name for the NodeManager. |
*-------------------------+-------------------------+------------------------+
| <<<yarn.nodemanager.container-executor.class>>> | | |
| | <<<org.apache.hadoop.yarn.server.nodemanager.LinuxContainerExecutor>>> | 
| | | Use LinuxContainerExecutor. | 
*-------------------------+-------------------------+------------------------+
| <<<yarn.nodemanager.linux-container-executor.group>>> | <hadoop> | |
| | | Unix group of the NodeManager. |
*-------------------------+-------------------------+------------------------+

    * <<<conf/mapred-site.xml>>>
    
      * Configurations for MapReduce JobHistory Server:

*-------------------------+-------------------------+------------------------+
|| Parameter              || Value                  || Notes                 |
*-------------------------+-------------------------+------------------------+
| <<<mapreduce.jobhistory.address>>> | | |
| | MapReduce JobHistory Server <host:port> | Default port is 10020. |
*-------------------------+-------------------------+------------------------+
| <<<mapreduce.jobhistory.keytab>>> | |
| | </etc/security/keytab/jhs.service.keytab> | |
| | | Kerberos keytab file for the MapReduce JobHistory Server. |
*-------------------------+-------------------------+------------------------+
| <<<mapreduce.jobhistory.principal>>> | jhs/_HOST@REALM.TLD | |
| | | Kerberos principal name for the MapReduce JobHistory Server. |
*-------------------------+-------------------------+------------------------+

        
  * {Operating the Hadoop Cluster}

  Once all the necessary configuration is complete, distribute the files to the 
  <<<HADOOP_CONF_DIR>>> directory on all the machines.

  This section also describes the various Unix users who should be starting the
  various components and uses the same Unix accounts and groups used previously:
  
    * Hadoop Startup
  
    To start a Hadoop cluster you will need to start both the HDFS and YARN 
    cluster.

    Format a new distributed filesystem as <hdfs>:
  
----
[hdfs]$ $HADOOP_PREFIX/bin/hdfs namenode -format <cluster_name>
----

    Start the HDFS with the following command, run on the designated NameNode
    as <hdfs>:
  
----
[hdfs]$ $HADOOP_PREFIX/sbin/hadoop-daemon.sh --config $HADOOP_CONF_DIR --script hdfs start namenode
----    	  

    Run a script to start DataNodes on all slaves as <root> with a special
    environment variable <<<HADOOP_SECURE_DN_USER>>> set to <hdfs>:

----
[root]$ HADOOP_SECURE_DN_USER=hdfs $HADOOP_PREFIX/sbin/hadoop-daemon.sh --config $HADOOP_CONF_DIR --script hdfs start datanode
----    	  
  
    Start the YARN with the following command, run on the designated 
    ResourceManager as <yarn>:
  
----
[yarn]$ $HADOOP_YARN_HOME/sbin/yarn-daemon.sh --config $HADOOP_CONF_DIR start resourcemanager 
----    	  

    Run a script to start NodeManagers on all slaves as <yarn>:

----
[yarn]$ $HADOOP_YARN_HOME/sbin/yarn-daemon.sh --config $HADOOP_CONF_DIR start nodemanager 
----    	  

    Start a standalone WebAppProxy server. Run on the WebAppProxy 
    server as <yarn>.  If multiple servers are used with load balancing
    it should be run on each of them:

----
[yarn]$ $HADOOP_YARN_HOME/bin/yarn start proxyserver --config $HADOOP_CONF_DIR  
----    	  

    Start the MapReduce JobHistory Server with the following command, run on the  
    designated server as <mapred>:
  
----
[mapred]$ $HADOOP_PREFIX/sbin/mr-jobhistory-daemon.sh start historyserver --config $HADOOP_CONF_DIR  
----    	  

    * Hadoop Shutdown      

    Stop the NameNode with the following command, run on the designated NameNode
    as <hdfs>:
  
----
[hdfs]$ $HADOOP_PREFIX/sbin/hadoop-daemon.sh --config $HADOOP_CONF_DIR --script hdfs stop namenode
----    	  

    Run a script to stop DataNodes on all slaves as <root>:

----
[root]$ $HADOOP_PREFIX/sbin/hadoop-daemon.sh --config $HADOOP_CONF_DIR --script hdfs stop datanode
----    	  
  
    Stop the ResourceManager with the following command, run on the designated 
    ResourceManager as <yarn>:
  
----
[yarn]$ $HADOOP_YARN_HOME/sbin/yarn-daemon.sh --config $HADOOP_CONF_DIR stop resourcemanager 
----    	  

    Run a script to stop NodeManagers on all slaves as <yarn>:

----
[yarn]$ $HADOOP_YARN_HOME/sbin/yarn-daemon.sh --config $HADOOP_CONF_DIR stop nodemanager 
----    	  

    Stop the WebAppProxy server. Run on the WebAppProxy  server as
    <yarn>.  If multiple servers are used with load balancing it
    should be run on each of them:

----
[yarn]$ $HADOOP_YARN_HOME/bin/yarn stop proxyserver --config $HADOOP_CONF_DIR  
----

    Stop the MapReduce JobHistory Server with the following command, run on the  
    designated server as <mapred>:

----
[mapred]$ $HADOOP_PREFIX/sbin/mr-jobhistory-daemon.sh stop historyserver --config $HADOOP_CONF_DIR  
----    	  
    
* {Web Interfaces}      

    Once the Hadoop cluster is up and running check the web-ui of the 
    components as described below:
    
*-------------------------+-------------------------+------------------------+
|| Daemon                 || Web Interface          || Notes                 |
*-------------------------+-------------------------+------------------------+
| NameNode | http://<nn_host:port>/ | Default HTTP port is 50070. |
*-------------------------+-------------------------+------------------------+
| ResourceManager | http://<rm_host:port>/ | Default HTTP port is 8088. |
*-------------------------+-------------------------+------------------------+
| MapReduce JobHistory Server | http://<jhs_host:port>/ | |
| | | Default HTTP port is 19888. |
*-------------------------+-------------------------+------------------------+