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| <h1> |
| HOD Configuration Guide |
| </h1> |
| <div id="minitoc-area"> |
| <ul class="minitoc"> |
| <li> |
| <a href="#1.+Introduction">1. Introduction</a> |
| </li> |
| <li> |
| <a href="#2.+Sections">2. Sections</a> |
| </li> |
| <li> |
| <a href="#3.+HOD+Configuration+Options">3. HOD Configuration Options</a> |
| <ul class="minitoc"> |
| <li> |
| <a href="#3.1+Common+configuration+options">3.1 Common configuration options</a> |
| </li> |
| <li> |
| <a href="#3.2+hod+options">3.2 hod options</a> |
| </li> |
| <li> |
| <a href="#3.3+resource_manager+options">3.3 resource_manager options</a> |
| </li> |
| <li> |
| <a href="#3.4+ringmaster+options">3.4 ringmaster options</a> |
| </li> |
| <li> |
| <a href="#3.5+gridservice-hdfs+options">3.5 gridservice-hdfs options</a> |
| </li> |
| <li> |
| <a href="#3.6+gridservice-mapred+options">3.6 gridservice-mapred options</a> |
| </li> |
| <li> |
| <a href="#3.7+hodring+options">3.7 hodring options</a> |
| </li> |
| </ul> |
| </li> |
| </ul> |
| </div> |
| |
| <a name="N1000C"></a><a name="1.+Introduction"></a> |
| <h2 class="h3">1. Introduction</h2> |
| <div class="section"> |
| <p>This guide discusses Hadoop on Demand (HOD) configuration sections and shows you how to work with the most important |
| and commonly used HOD configuration options.</p> |
| <p>Configuration options |
| can be specified in two ways: a configuration file |
| in the INI format, and as command line options to the HOD shell, |
| specified in the format --section.option[=value]. If the same option is |
| specified in both places, the value specified on the command line |
| overrides the value in the configuration file.</p> |
| <p> |
| To get a simple description of all configuration options, type: |
| </p> |
| <table class="ForrestTable" cellspacing="1" cellpadding="4"> |
| <tr> |
| <td colspan="1" rowspan="1"><span class="codefrag">$ hod --verbose-help</span></td> |
| </tr> |
| </table> |
| </div> |
| |
| |
| <a name="N10024"></a><a name="2.+Sections"></a> |
| <h2 class="h3">2. Sections</h2> |
| <div class="section"> |
| <p>HOD organizes configuration options into these sections:</p> |
| <ul> |
| |
| <li> hod: Options for the HOD client</li> |
| |
| <li> resource_manager: Options for specifying which resource manager |
| to use, and other parameters for using that resource manager</li> |
| |
| <li> ringmaster: Options for the RingMaster process, </li> |
| |
| <li> hodring: Options for the HodRing processes</li> |
| |
| <li> gridservice-mapred: Options for the Map/Reduce daemons</li> |
| |
| <li> gridservice-hdfs: Options for the HDFS daemons.</li> |
| |
| </ul> |
| </div> |
| |
| |
| <a name="N10043"></a><a name="3.+HOD+Configuration+Options"></a> |
| <h2 class="h3">3. HOD Configuration Options</h2> |
| <div class="section"> |
| <p>The following section describes configuration options common to most |
| HOD sections followed by sections that describe configuration options |
| specific to each HOD section.</p> |
| <a name="N1004C"></a><a name="3.1+Common+configuration+options"></a> |
| <h3 class="h4">3.1 Common configuration options</h3> |
| <p>Certain configuration options are defined in most of the sections of |
| the HOD configuration. Options defined in a section, are used by the |
| process for which that section applies. These options have the same |
| meaning, but can have different values in each section. |
| </p> |
| <ul> |
| |
| <li>temp-dir: Temporary directory for usage by the HOD processes. Make |
| sure that the users who will run hod have rights to create |
| directories under the directory specified here. If you |
| wish to make this directory vary across allocations, |
| you can make use of the environmental variables which will |
| be made available by the resource manager to the HOD |
| processes. For example, in a Torque setup, having |
| --ringmaster.temp-dir=/tmp/hod-temp-dir.$PBS_JOBID would |
| let ringmaster use different temp-dir for each |
| allocation; Torque expands this variable before starting |
| the ringmaster.</li> |
| |
| |
| <li>debug: Numeric value from 1-4. 4 produces the most log information, |
| and 1 the least.</li> |
| |
| |
| <li>log-dir: Directory where log files are stored. By default, this is |
| <install-location>/logs/. The restrictions and notes for the |
| temp-dir variable apply here too. |
| </li> |
| |
| |
| <li>xrs-port-range: Range of ports, among which an available port shall |
| be picked for use to run an XML-RPC server.</li> |
| |
| |
| <li>http-port-range: Range of ports, among which an available port shall |
| be picked for use to run an HTTP server.</li> |
| |
| |
| <li>java-home: Location of Java to be used by Hadoop.</li> |
| |
| <li>syslog-address: Address to which a syslog daemon is bound to. The format |
| of the value is host:port. If configured, HOD log messages |
| will be logged to syslog using this value.</li> |
| |
| |
| </ul> |
| <a name="N1006E"></a><a name="3.2+hod+options"></a> |
| <h3 class="h4">3.2 hod options</h3> |
| <ul> |
| |
| <li>cluster: Descriptive name given to the cluster. For Torque, this is |
| specified as a 'Node property' for every node in the cluster. |
| HOD uses this value to compute the number of available nodes.</li> |
| |
| |
| <li>client-params: Comma-separated list of hadoop config parameters |
| specified as key-value pairs. These will be used to |
| generate a hadoop-site.xml on the submit node that |
| should be used for running Map/Reduce jobs.</li> |
| |
| <li>job-feasibility-attr: Regular expression string that specifies |
| whether and how to check job feasibility - resource |
| manager or scheduler limits. The current |
| implementation corresponds to the torque job |
| attribute 'comment' and by default is disabled. |
| When set, HOD uses it to decide what type |
| of limit violation is triggered and either |
| deallocates the cluster or stays in queued state |
| according as the request is beyond maximum limits or |
| the cumulative usage has crossed maximum limits. |
| The torque comment attribute may be updated |
| periodically by an external mechanism. For example, |
| comment attribute can be updated by running <a href="hod_admin_guide.html#checklimits.sh+-+Tool+to+update+torque+comment+field+reflecting+resource+limits"> |
| checklimits.sh</a> script in hod/support directory, |
| and then setting job-feasibility-attr equal to the |
| value TORQUE_USER_LIMITS_COMMENT_FIELD, |
| "User-limits exceeded. Requested:([0-9]*) |
| Used:([0-9]*) MaxLimit:([0-9]*)", will make HOD |
| behave accordingly. |
| </li> |
| |
| </ul> |
| <a name="N10085"></a><a name="3.3+resource_manager+options"></a> |
| <h3 class="h4">3.3 resource_manager options</h3> |
| <ul> |
| |
| <li>queue: Name of the queue configured in the resource manager to which |
| jobs are to be submitted.</li> |
| |
| |
| <li>batch-home: Install directory to which 'bin' is appended and under |
| which the executables of the resource manager can be |
| found.</li> |
| |
| |
| <li>env-vars: Comma-separated list of key-value pairs, |
| expressed as key=value, which would be passed to the jobs |
| launched on the compute nodes. |
| For example, if the python installation is |
| in a non-standard location, one can set the environment |
| variable 'HOD_PYTHON_HOME' to the path to the python |
| executable. The HOD processes launched on the compute nodes |
| can then use this variable.</li> |
| |
| <li>options: Comma-separated list of key-value pairs, |
| expressed as |
| <option>:<sub-option>=<value>. When |
| passing to the job submission program, these are expanded |
| as -<option> <sub-option>=<value>. These |
| are generally used for specifying additional resource |
| contraints for scheduling. For instance, with a Torque |
| setup, one can specify |
| --resource_manager.options='l:arch=x86_64' for |
| constraining the nodes being allocated to a particular |
| architecture; this option will be passed to Torque's qsub |
| command as "-l arch=x86_64".</li> |
| |
| </ul> |
| <a name="N1009B"></a><a name="3.4+ringmaster+options"></a> |
| <h3 class="h4">3.4 ringmaster options</h3> |
| <ul> |
| |
| <li>work-dirs: Comma-separated list of paths that will serve |
| as the root for directories that HOD generates and passes |
| to Hadoop for use to store DFS and Map/Reduce data. For |
| example, |
| this is where DFS data blocks will be stored. Typically, |
| as many paths are specified as there are disks available |
| to ensure all disks are being utilized. The restrictions |
| and notes for the temp-dir variable apply here too.</li> |
| |
| <li>max-master-failures: Number of times a hadoop master |
| daemon can fail to launch, beyond which HOD will fail |
| the cluster allocation altogether. In HOD clusters, |
| sometimes there might be a single or few "bad" nodes due |
| to issues like missing java, missing or incorrect version |
| of Hadoop etc. When this configuration variable is set |
| to a positive integer, the RingMaster returns an error |
| to the client only when the number of times a hadoop |
| master (JobTracker or NameNode) fails to start on these |
| bad nodes because of above issues, exceeds the specified |
| value. If the number is not exceeded, the next HodRing |
| which requests for a command to launch is given the same |
| hadoop master again. This way, HOD tries its best for a |
| successful allocation even in the presence of a few bad |
| nodes in the cluster. |
| </li> |
| |
| <li>workers_per_ring: Number of workers per service per HodRing. |
| By default this is set to 1. If this configuration |
| variable is set to a value 'n', the HodRing will run |
| 'n' instances of the workers (TaskTrackers or DataNodes) |
| on each node acting as a slave. This can be used to run |
| multiple workers per HodRing, so that the total number of |
| workers in a HOD cluster is not limited by the total |
| number of nodes requested during allocation. However, note |
| that this will mean each worker should be configured to use |
| only a proportional fraction of the capacity of the |
| resources on the node. In general, this feature is only |
| useful for testing and simulation purposes, and not for |
| production use.</li> |
| |
| </ul> |
| <a name="N100AE"></a><a name="3.5+gridservice-hdfs+options"></a> |
| <h3 class="h4">3.5 gridservice-hdfs options</h3> |
| <ul> |
| |
| <li>external: If false, indicates that a HDFS cluster must be |
| bought up by the HOD system, on the nodes which it |
| allocates via the allocate command. Note that in that case, |
| when the cluster is de-allocated, it will bring down the |
| HDFS cluster, and all the data will be lost. |
| If true, it will try and connect to an externally configured |
| HDFS system. |
| Typically, because input for jobs are placed into HDFS |
| before jobs are run, and also the output from jobs in HDFS |
| is required to be persistent, an internal HDFS cluster is |
| of little value in a production system. However, it allows |
| for quick testing.</li> |
| |
| |
| <li>host: Hostname of the externally configured NameNode, if any</li> |
| |
| |
| <li>fs_port: Port to which NameNode RPC server is bound.</li> |
| |
| |
| <li>info_port: Port to which the NameNode web UI server is bound.</li> |
| |
| |
| <li>pkgs: Installation directory, under which bin/hadoop executable is |
| located. This can be used to use a pre-installed version of |
| Hadoop on the cluster.</li> |
| |
| |
| <li>server-params: Comma-separated list of hadoop config parameters |
| specified key-value pairs. These will be used to |
| generate a hadoop-site.xml that will be used by the |
| NameNode and DataNodes.</li> |
| |
| |
| <li>final-server-params: Same as above, except they will be marked final.</li> |
| |
| </ul> |
| <a name="N100CD"></a><a name="3.6+gridservice-mapred+options"></a> |
| <h3 class="h4">3.6 gridservice-mapred options</h3> |
| <ul> |
| |
| <li>external: If false, indicates that a Map/Reduce cluster must be |
| bought up by the HOD system on the nodes which it allocates |
| via the allocate command. |
| If true, if will try and connect to an externally |
| configured Map/Reduce system.</li> |
| |
| |
| <li>host: Hostname of the externally configured JobTracker, if any</li> |
| |
| |
| <li>tracker_port: Port to which the JobTracker RPC server is bound</li> |
| |
| |
| <li>info_port: Port to which the JobTracker web UI server is bound.</li> |
| |
| |
| <li>pkgs: Installation directory, under which bin/hadoop executable is |
| located</li> |
| |
| |
| <li>server-params: Comma-separated list of hadoop config parameters |
| specified key-value pairs. These will be used to |
| generate a hadoop-site.xml that will be used by the |
| JobTracker and TaskTrackers</li> |
| |
| |
| <li>final-server-params: Same as above, except they will be marked final.</li> |
| |
| </ul> |
| <a name="N100EC"></a><a name="3.7+hodring+options"></a> |
| <h3 class="h4">3.7 hodring options</h3> |
| <ul> |
| |
| <li>mapred-system-dir-root: Directory in the DFS under which HOD will |
| generate sub-directory names and pass the full path |
| as the value of the 'mapred.system.dir' configuration |
| parameter to Hadoop daemons. The format of the full |
| path will be value-of-this-option/userid/mapredsystem/cluster-id. |
| Note that the directory specified here should be such |
| that all users can create directories under this, if |
| permissions are enabled in HDFS. Setting the value of |
| this option to /user will make HOD use the user's |
| home directory to generate the mapred.system.dir value.</li> |
| |
| |
| <li>log-destination-uri: URL describing a path in an external, static DFS or the |
| cluster node's local file system where HOD will upload |
| Hadoop logs when a cluster is deallocated. To specify a |
| DFS path, use the format 'hdfs://path'. To specify a |
| cluster node's local file path, use the format 'file://path'. |
| |
| When clusters are deallocated by HOD, the hadoop logs will |
| be deleted as part of HOD's cleanup process. To ensure these |
| logs persist, you can use this configuration option. |
| |
| The format of the path is |
| value-of-this-option/userid/hod-logs/cluster-id |
| |
| Note that the directory you specify here must be such that all |
| users can create sub-directories under this. Setting this value |
| to hdfs://user will make the logs come in the user's home directory |
| in DFS.</li> |
| |
| |
| <li>pkgs: Installation directory, under which bin/hadoop executable is located. This will |
| be used by HOD to upload logs if a HDFS URL is specified in log-destination-uri |
| option. Note that this is useful if the users are using a tarball whose version |
| may differ from the external, static HDFS version.</li> |
| |
| |
| </ul> |
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| |
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