HADOOP-3695. Provide an ability to start multiple workers per node. Contributed by Vinod Kumar Vavilapalli

git-svn-id: https://svn.apache.org/repos/asf/hadoop/core/trunk@675194 13f79535-47bb-0310-9956-ffa450edef68

docs/changes.html

@@ -95,7 +95,7 @@ naming convention,such as, hadoop.rm.queue.queue-name.property-name.<br />(Heman
     </ol>
   </li>
   <li><a href="javascript:toggleList('trunk_(unreleased_changes)_._improvements_')">  IMPROVEMENTS
-</a>&nbsp;&nbsp;&nbsp;(6)
+</a>&nbsp;&nbsp;&nbsp;(7)
     <ol id="trunk_(unreleased_changes)_._improvements_">
       <li><a href="http://issues.apache.org/jira/browse/HADOOP-3577">HADOOP-3577</a>. Tools to inject blocks into name node and simulated
 data nodes for testing.<br />(Sanjay Radia via hairong)</li>
@@ -106,6 +106,8 @@ Loughran via omalley)</li>
       <li><a href="http://issues.apache.org/jira/browse/HADOOP-3543">HADOOP-3543</a>. Update the copyright year to 2008.<br />(cdouglas via omalley)</li>
       <li><a href="http://issues.apache.org/jira/browse/HADOOP-3587">HADOOP-3587</a>. Add a unit test for the contrib/data_join framework.<br />(cdouglas)</li>
       <li><a href="http://issues.apache.org/jira/browse/HADOOP-3402">HADOOP-3402</a>. Add terasort example program<br />(omalley)</li>
+      <li><a href="http://issues.apache.org/jira/browse/HADOOP-3660">HADOOP-3660</a>. Add replication factor for injecting blocks in simulated
+datanodes.<br />(Sanjay Radia via cdouglas)</li>
     </ol>
   </li>
   <li><a href="javascript:toggleList('trunk_(unreleased_changes)_._optimizations_')">  OPTIMIZATIONS
@@ -130,7 +132,7 @@ omalley)</li>
 </a></h2>
 <ul id="release_0.18.0_-_unreleased_">
   <li><a href="javascript:toggleList('release_0.18.0_-_unreleased_._incompatible_changes_')">  INCOMPATIBLE CHANGES
-</a>&nbsp;&nbsp;&nbsp;(22)
+</a>&nbsp;&nbsp;&nbsp;(23)
     <ol id="release_0.18.0_-_unreleased_._incompatible_changes_">
       <li><a href="http://issues.apache.org/jira/browse/HADOOP-2703">HADOOP-2703</a>.  The default options to fsck skips checking files
 that are being written to. The output of fsck is incompatible
@@ -202,6 +204,9 @@ of the keytype if the type does not define a WritableComparator. Calling
 the superclass compare will throw a NullPointerException. Also define
 a RawComparator for NullWritable and permit it to be written as a key
 to SequenceFiles.<br />(cdouglas)</li>
+      <li><a href="http://issues.apache.org/jira/browse/HADOOP-3673">HADOOP-3673</a>. Avoid deadlock caused by DataNode RPC receoverBlock().
+(Tsz Wo (Nicholas), SZE via rangadi)
+</li>
     </ol>
   </li>
   <li><a href="javascript:toggleList('release_0.18.0_-_unreleased_._new_features_')">  NEW FEATURES
@@ -378,7 +383,7 @@ InputFormat.validateInput.<br />(tomwhite via omalley)</li>
     </ol>
   </li>
   <li><a href="javascript:toggleList('release_0.18.0_-_unreleased_._bug_fixes_')">  BUG FIXES
-</a>&nbsp;&nbsp;&nbsp;(115)
+</a>&nbsp;&nbsp;&nbsp;(117)
     <ol id="release_0.18.0_-_unreleased_._bug_fixes_">
       <li><a href="http://issues.apache.org/jira/browse/HADOOP-2905">HADOOP-2905</a>. 'fsck -move' triggers NPE in NameNode.<br />(Lohit Vjayarenu via rangadi)</li>
       <li>Increment ClientProtocol.versionID missed by <a href="http://issues.apache.org/jira/browse/HADOOP-2585">HADOOP-2585</a>.<br />(shv)</li>
@@ -605,33 +610,50 @@ conform to style guidelines.<br />(Amareshwari Sriramadasu via cdouglas)</li>
 classpath jars.<br />(Brice Arnould via nigel)</li>
       <li><a href="http://issues.apache.org/jira/browse/HADOOP-3692">HADOOP-3692</a>. Fix documentation for Cluster setup and Quick start guides.<br />(Amareshwari Sriramadasu via ddas)</li>
       <li><a href="http://issues.apache.org/jira/browse/HADOOP-3691">HADOOP-3691</a>. Fix streaming and tutorial docs.<br />(Jothi Padmanabhan via ddas)</li>
+      <li><a href="http://issues.apache.org/jira/browse/HADOOP-3630">HADOOP-3630</a>. Fix NullPointerException in CompositeRecordReader from empty
+sources<br />(cdouglas)</li>
+      <li><a href="http://issues.apache.org/jira/browse/HADOOP-3706">HADOOP-3706</a>. Fix a ClassLoader issue in the mapred.join Parser that
+prevents it from loading user-specified InputFormats.<br />(Jingkei Ly via cdouglas)</li>
     </ol>
   </li>
 </ul>
 <h2><a href="javascript:toggleList('older')">Older Releases</a></h2>
 <ul id="older">
-<h3><a href="javascript:toggleList('release_0.17.1_-_unreleased_')">Release 0.17.1 - Unreleased
+<h3><a href="javascript:toggleList('release_0.17.2_-_unreleased_')">Release 0.17.2 - Unreleased
+</a></h3>
+<ul id="release_0.17.2_-_unreleased_">
+  <li><a href="javascript:toggleList('release_0.17.2_-_unreleased_._bug_fixes_')">  BUG FIXES
+</a>&nbsp;&nbsp;&nbsp;(3)
+    <ol id="release_0.17.2_-_unreleased_._bug_fixes_">
+      <li><a href="http://issues.apache.org/jira/browse/HADOOP-3681">HADOOP-3681</a>. DFSClient can get into an infinite loop while closing
+a file if there are some errors.<br />(Lohit Vijayarenu via rangadi)</li>
+      <li><a href="http://issues.apache.org/jira/browse/HADOOP-3002">HADOOP-3002</a>. Hold off block removal while in safe mode.<br />(shv)</li>
+      <li><a href="http://issues.apache.org/jira/browse/HADOOP-3685">HADOOP-3685</a>. Unbalanced replication target.<br />(hairong)</li>
+    </ol>
+  </li>
+</ul>
+<h3><a href="javascript:toggleList('release_0.17.1_-_2008-06-23_')">Release 0.17.1 - 2008-06-23
 </a></h3>
-<ul id="release_0.17.1_-_unreleased_">
-  <li><a href="javascript:toggleList('release_0.17.1_-_unreleased_._incompatible_changes_')">  INCOMPATIBLE CHANGES
+<ul id="release_0.17.1_-_2008-06-23_">
+  <li><a href="javascript:toggleList('release_0.17.1_-_2008-06-23_._incompatible_changes_')">  INCOMPATIBLE CHANGES
 </a>&nbsp;&nbsp;&nbsp;(1)
-    <ol id="release_0.17.1_-_unreleased_._incompatible_changes_">
+    <ol id="release_0.17.1_-_2008-06-23_._incompatible_changes_">
       <li><a href="http://issues.apache.org/jira/browse/HADOOP-3565">HADOOP-3565</a>. Fix the Java serialization, which is not enabled by
 default, to clear the state of the serializer between objects.<br />(tomwhite via omalley)</li>
     </ol>
   </li>
-  <li><a href="javascript:toggleList('release_0.17.1_-_unreleased_._improvements_')">  IMPROVEMENTS
+  <li><a href="javascript:toggleList('release_0.17.1_-_2008-06-23_._improvements_')">  IMPROVEMENTS
 </a>&nbsp;&nbsp;&nbsp;(2)
-    <ol id="release_0.17.1_-_unreleased_._improvements_">
+    <ol id="release_0.17.1_-_2008-06-23_._improvements_">
       <li><a href="http://issues.apache.org/jira/browse/HADOOP-3522">HADOOP-3522</a>. Improve documentation on reduce pointing out that
 input keys and values will be reused.<br />(omalley)</li>
       <li><a href="http://issues.apache.org/jira/browse/HADOOP-3487">HADOOP-3487</a>. Balancer uses thread pools for managing its threads;
 therefore provides better resource management.<br />(hairong)</li>
     </ol>
   </li>
-  <li><a href="javascript:toggleList('release_0.17.1_-_unreleased_._bug_fixes_')">  BUG FIXES
+  <li><a href="javascript:toggleList('release_0.17.1_-_2008-06-23_._bug_fixes_')">  BUG FIXES
 </a>&nbsp;&nbsp;&nbsp;(14)
-    <ol id="release_0.17.1_-_unreleased_._bug_fixes_">
+    <ol id="release_0.17.1_-_2008-06-23_._bug_fixes_">
       <li><a href="http://issues.apache.org/jira/browse/HADOOP-2159">HADOOP-2159</a> Namenode stuck in safemode. The counter blockSafe should
 not be decremented for invalid blocks.<br />(hairong)</li>
       <li><a href="http://issues.apache.org/jira/browse/HADOOP-3472">HADOOP-3472</a> MapFile.Reader getClosest() function returns incorrect results

docs/hod_config_guide.html

@@ -384,7 +384,8 @@ document.write("Last Published: " + document.lastModified);
           
 <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 e.g.
+                       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
@@ -406,9 +407,23 @@ document.write("Last Published: " + document.lastModified);
                        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="N100A5"></a><a name="3.5+gridservice-hdfs+options"></a>
+<a name="N100A8"></a><a name="3.5+gridservice-hdfs+options"></a>
 <h3 class="h4">3.5 gridservice-hdfs options</h3>
 <ul>
           
@@ -449,7 +464,7 @@ document.write("Last Published: " + document.lastModified);
 <li>final-server-params: Same as above, except they will be marked final.</li>
         
 </ul>
-<a name="N100C4"></a><a name="3.6+gridservice-mapred+options"></a>
+<a name="N100C7"></a><a name="3.6+gridservice-mapred+options"></a>
 <h3 class="h4">3.6 gridservice-mapred options</h3>
 <ul>
           
@@ -482,7 +497,7 @@ document.write("Last Published: " + document.lastModified);
 <li>final-server-params: Same as above, except they will be marked final.</li>
         
 </ul>
-<a name="N100E3"></a><a name="3.7+hodring+options"></a>
+<a name="N100E6"></a><a name="3.7+hodring+options"></a>
 <h3 class="h4">3.7 hodring options</h3>
 <ul>
           

src/contrib/hod/CHANGES.txt

@@ -6,6 +6,9 @@ Trunk (unreleased changes)
 
   NEW FEATURES
 
+    HADOOP-3695. Provide an ability to start multiple workers per node.
+    (Vinod Kumar Vavilapalli via yhemanth)
+
   IMPROVEMENTS
 
   OPTIMIZATIONS

src/contrib/hod/bin/hod

@@ -229,8 +229,10 @@ defList = { 'hod' : (
 
              ('max-master-failures', 'pos_int', 
               'Defines how many times a master can fail before' \
-              ' failing cluster allocation', False, 5, True, True)),
+              ' failing cluster allocation', False, 5, True, True),
 
+             ('workers_per_ring', 'pos_int', 'Defines number of workers per service per hodring',
+             False, 1, False, True)),
 
             'gridservice-mapred' : (
              ('external', 'bool', "Connect to an already running MapRed?",
@@ -517,6 +519,12 @@ if __name__ == '__main__':
           "The log destiniation uri must be of type local:// or hdfs://."))
         sys.exit(1)
   
+    if hodConfig['ringmaster']['workers_per_ring'] < 1:
+      printErrors(hodConfig.var_error('ringmaster', 'workers_per_ring',
+                "ringmaster.workers_per_ring must be a positive integer " +
+                "greater than or equal to 1"))
+      sys.exit(1)
+                        
     ## TODO : end of should move the dependency verification to hodConfig.verif
       
     hodConfig['hod']['base-dir'] = rootDirectory

src/contrib/hod/bin/ringmaster

@@ -117,7 +117,10 @@ defList = { 'ringmaster' : (
 
              ('max-master-failures', 'pos_int', 
               'Defines how many times a master can fail before' \
-              ' failing cluster allocation', False, 5, True, True)),
+              ' failing cluster allocation', False, 5, True, True),
+
+             ('workers_per_ring', 'pos_int', 'Defines number of workers per service per hodring',
+              False, 1, False, True)),
 
             'resource_manager' : (
              ('id', 'string', 'Batch scheduler ID: torque|condor.',

src/contrib/hod/hodlib/GridServices/hdfs.py

@@ -76,7 +76,8 @@ class HdfsExternal(MasterSlave):
 class Hdfs(MasterSlave):
 
   def __init__(self, serviceDesc, nodePool, required_node, version, \
-                                        format=True, upgrade=False):
+                                        format=True, upgrade=False,
+                                        workers_per_ring = 1):
     MasterSlave.__init__(self, serviceDesc, nodePool, required_node)
     self.masterNode = None
     self.masterAddr = None
@@ -87,6 +88,7 @@ class Hdfs(MasterSlave):
     self.upgrade = upgrade
     self.workers = []
     self.version = version
+    self.workers_per_ring = workers_per_ring
 
   def getMasterRequest(self):
     req = NodeRequest(1, [], False)
@@ -117,8 +119,11 @@ class Hdfs(MasterSlave):
     return adminCommands
 
   def getWorkerCommands(self, serviceDict):
-    cmdDesc = self._getDataNodeCommand()
-    return [cmdDesc]
+    workerCmds = []
+    for id in range(1, self.workers_per_ring + 1):
+      workerCmds.append(self._getDataNodeCommand(str(id)))
+
+    return workerCmds
 
   def setMasterNodes(self, list):
     node = list[0]
@@ -250,7 +255,7 @@ class Hdfs(MasterSlave):
     cmd = CommandDesc(dict)
     return cmd
  
-  def _getDataNodeCommand(self):
+  def _getDataNodeCommand(self, id):
 
     sd = self.serviceDesc
 
@@ -282,6 +287,14 @@ class Hdfs(MasterSlave):
       # TODO: check for major as well as minor versions
       attrs['dfs.datanode.ipc.address'] = 'fillinhostport'
                     
+    # unique workdirs in case of multiple datanodes per hodring
+    pd = []
+    for dir in parentDirs:
+      dir = dir + "-" + id
+      pd.append(dir)
+    parentDirs = pd
+    # end of unique workdirs
+
     self._setWorkDirs(workDirs, envs, attrs, parentDirs, 'hdfs-dn')
 
     dict = { 'name' : 'datanode' }
@@ -292,7 +305,7 @@ class Hdfs(MasterSlave):
     dict['workdirs'] = workDirs
     dict['final-attrs'] = attrs
     dict['attrs'] = sd.getAttrs()
-
+ 
     cmd = CommandDesc(dict)
     return cmd
 

src/contrib/hod/hodlib/GridServices/mapred.py

@@ -82,7 +82,8 @@ class MapReduceExternal(MasterSlave):
   
 class MapReduce(MasterSlave):
 
-  def __init__(self, serviceDesc, workDirs,required_node, version):
+  def __init__(self, serviceDesc, workDirs,required_node, version,
+                workers_per_ring = 1):
     MasterSlave.__init__(self, serviceDesc, workDirs,required_node)
 
     self.masterNode = None
@@ -91,6 +92,7 @@ class MapReduce(MasterSlave):
     self.workers = []
     self.required_node = required_node
     self.version = version
+    self.workers_per_ring = workers_per_ring
 
   def isLaunchable(self, serviceDict):
     hdfs = serviceDict['hdfs']
@@ -116,8 +118,11 @@ class MapReduce(MasterSlave):
 
     hdfs = serviceDict['hdfs']
 
-    cmdDesc = self._getTaskTrackerCommand(hdfs)
-    return [cmdDesc]
+    workerCmds = []
+    for id in range(1, self.workers_per_ring + 1):
+      workerCmds.append(self._getTaskTrackerCommand(str(id), hdfs))
+      
+    return workerCmds
 
   def setMasterNodes(self, list):
     node = list[0]
@@ -217,7 +222,7 @@ class MapReduce(MasterSlave):
     cmd = CommandDesc(dict)
     return cmd
 
-  def _getTaskTrackerCommand(self, hdfs):
+  def _getTaskTrackerCommand(self, id, hdfs):
 
     sd = self.serviceDesc
 
@@ -245,6 +250,14 @@ class MapReduce(MasterSlave):
       if 'mapred.task.tracker.http.address' not in attrs:
         attrs['mapred.task.tracker.http.address'] = 'fillinhostport'
 
+    # unique parentDirs in case of multiple tasktrackers per hodring
+    pd = []
+    for dir in parentDirs:
+      dir = dir + "-" + id
+      pd.append(dir)
+    parentDirs = pd
+    # end of unique workdirs
+
     self._setWorkDirs(workDirs, envs, attrs, parentDirs, 'mapred-tt')
 
     dict = { 'name' : 'tasktracker' }

src/contrib/hod/hodlib/RingMaster/ringMaster.py

@@ -553,6 +553,8 @@ class RingMaster:
     self.__isStopped = False # to let main exit
     self.__exitCode = 0 # exit code with which the ringmaster main method should return
 
+    self.workers_per_ring = self.cfg['ringmaster']['workers_per_ring']
+
     self.__initialize_signal_handlers()
     
     sdd = self.cfg['servicedesc']
@@ -609,7 +611,8 @@ class RingMaster:
         hdfs = HdfsExternal(hdfsDesc, workDirs, version=int(hadoopVers['minor']))
         hdfs.setMasterParams( self.cfg['gridservice-hdfs'] )
       else:
-        hdfs = Hdfs(hdfsDesc, workDirs, 0, version=int(hadoopVers['minor']))
+        hdfs = Hdfs(hdfsDesc, workDirs, 0, version=int(hadoopVers['minor']),
+                    workers_per_ring = self.workers_per_ring)
 
       self.serviceDict[hdfs.getName()] = hdfs
       
@@ -619,7 +622,8 @@ class RingMaster:
         mr = MapReduceExternal(mrDesc, workDirs, version=int(hadoopVers['minor']))
         mr.setMasterParams( self.cfg['gridservice-mapred'] )
       else:
-        mr = MapReduce(mrDesc, workDirs,1, version=int(hadoopVers['minor']))
+        mr = MapReduce(mrDesc, workDirs,1, version=int(hadoopVers['minor']),
+                       workers_per_ring = self.workers_per_ring)
 
       self.serviceDict[mr.getName()] = mr
     except:

src/contrib/hod/support/logcondense.py

@@ -113,11 +113,10 @@ def runcondense():
   # otherwise only JobTracker logs. Likewise, in case of dynamic dfs, we must also look for
   # deleting datanode logs
   filteredNames = ['jobtracker']
-  deletedNamePrefixes = ['0-tasktracker-*']
+  deletedNamePrefixes = ['*-tasktracker-*']
   if options.dynamicdfs == 'true':
     filteredNames.append('namenode')
-    deletedNamePrefixes.append('1-tasktracker-*')
-    deletedNamePrefixes.append('0-datanode-*')
+    deletedNamePrefixes.append('*-datanode-*')
 
   filepath = '%s/\*/hod-logs/' % (options.log)
   cmd = getDfsCommand(options, "-lsr " + filepath)
@@ -128,7 +127,7 @@ def runcondense():
     try:
       m = re.match("^.*\s(.*)\n$", line)
       filename = m.group(1)
-      # file name format: <prefix>/<user>/hod-logs/<jobid>/[0-1]-[jobtracker|tasktracker|datanode|namenode|]-hostname-YYYYMMDDtime-random.tar.gz
+      # file name format: <prefix>/<user>/hod-logs/<jobid>/[0-9]*-[jobtracker|tasktracker|datanode|namenode|]-hostname-YYYYMMDDtime-random.tar.gz
       # first strip prefix:
       if filename.startswith(options.log):
         filename = filename.lstrip(options.log)

src/contrib/hod/testing/testRingmasterRPCs.py

@@ -30,6 +30,28 @@ from hodlib.GridServices import *
 from hodlib.Common.desc import ServiceDesc
 from hodlib.RingMaster.ringMaster import _LogMasterSources
 
+configuration = {
+       'hod': {}, 
+      'resource_manager': {
+                            'id': 'torque', 
+                            'batch-home': '/home/y/'
+                          }, 
+       'ringmaster': {
+                      'max-connect' : 2,
+                      'max-master-failures' : 5
+                     }, 
+       'hodring': {
+                  }, 
+       'gridservice-mapred': { 
+                              'id': 'mapred' 
+                             } ,
+       'gridservice-hdfs': { 
+                              'id': 'hdfs' 
+                            }, 
+       'servicedesc' : {} ,
+       'nodepooldesc': {} , 
+       }
+
 # All test-case classes should have the naming convention test_.*
 class test_MINITEST1(unittest.TestCase):
   def setUp(self):
@@ -45,12 +67,49 @@ class test_MINITEST1(unittest.TestCase):
   def tearDown(self):
     pass
 
-class test_MINITEST2(unittest.TestCase):
+class test_Multiple_Workers(unittest.TestCase):
   def setUp(self):
+    self.config = configuration
+    self.config['ringmaster']['workers_per_ring'] = 2
+
+    hdfsDesc = self.config['servicedesc']['hdfs'] = ServiceDesc(self.config['gridservice-hdfs'])
+    mrDesc = self.config['servicedesc']['mapred'] = ServiceDesc(self.config['gridservice-mapred'])
+
+    self.hdfs = Hdfs(hdfsDesc, [], 0, 19, workers_per_ring = \
+                                 self.config['ringmaster']['workers_per_ring'])
+    self.mr = MapReduce(mrDesc, [],1, 19, workers_per_ring = \
+                                 self.config['ringmaster']['workers_per_ring'])
+    
+    self.log = logging.getLogger()
     pass
 
   # All testMethods have to have their names start with 'test'
-  def testSuccess(self):
+  def testWorkersCount(self):
+    self.serviceDict = {}
+    self.serviceDict[self.hdfs.getName()] = self.hdfs
+    self.serviceDict[self.mr.getName()] = self.mr
+    self.rpcSet = _LogMasterSources(self.serviceDict, self.config, None, self.log, None)
+
+    cmdList = self.rpcSet.getCommand('host1')
+    self.assertEquals(len(cmdList), 2)
+    self.assertEquals(cmdList[0].dict['argv'][0], 'namenode')
+    self.assertEquals(cmdList[1].dict['argv'][0], 'namenode')
+    addParams = ['fs.default.name=host1:51234', 'dfs.http.address=host1:5125' ]
+    self.rpcSet.addMasterParams('host1', addParams)
+    # print "NN is launched"
+
+    cmdList = self.rpcSet.getCommand('host2')
+    self.assertEquals(len(cmdList), 1)
+    self.assertEquals(cmdList[0].dict['argv'][0], 'jobtracker')
+    addParams = ['mapred.job.tracker=host2:51236',
+                 'mapred.job.tracker.http.address=host2:51237']
+    self.rpcSet.addMasterParams('host2', addParams)
+    # print "JT is launched"
+
+    cmdList = self.rpcSet.getCommand('host3')
+    # Verify the workers count per ring : TTs + DNs
+    self.assertEquals(len(cmdList),
+                      self.config['ringmaster']['workers_per_ring'] * 2)
     pass
     
   def testFailure(self):
@@ -61,27 +120,7 @@ class test_MINITEST2(unittest.TestCase):
 
 class test_GetCommand(unittest.TestCase):
   def setUp(self):
-    self.config = {
-       'hod': {}, 
-      'resource_manager': {
-                            'id': 'torque', 
-                            'batch-home': '/home/y/'
-                          }, 
-       'ringmaster': {
-                      'max-connect' : 2,
-                      'max-master-failures' : 5
-                     }, 
-       'hodring': {
-                  }, 
-       'gridservice-mapred': { 
-                              'id': 'mapred' 
-                             } ,
-       'gridservice-hdfs': { 
-                              'id': 'hdfs' 
-                            }, 
-       'servicedesc' : {} ,
-       'nodepooldesc': {} , 
-       }
+    self.config = configuration
 
     hdfsDesc = self.config['servicedesc']['hdfs'] = ServiceDesc(self.config['gridservice-hdfs'])
     mrDesc = self.config['servicedesc']['mapred'] = ServiceDesc(self.config['gridservice-mapred'])

src/docs/src/documentation/content/xdocs/hod_config_guide.xml

@@ -156,7 +156,8 @@
         <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 e.g.
+                       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
@@ -177,6 +178,19 @@
                        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>
       </section>