RxHadoopMR: Generate Hadoop Map Reduce Compute Context

Artigo
07/15/2019

Description

DEPRECATED: Creates a compute context for use with a Hadoop cluster.

RxHadoopMR compute context is deprecated. Please consider using RxSpark compute context instead.

Usage

  RxHadoopMR(object, 
                hdfsShareDir = paste( "/user/RevoShare", Sys.info()[["user"]], sep="/" ),
                shareDir = paste( "/var/RevoShare", Sys.info()[["user"]], sep="/" ),
                clientShareDir = rxGetDefaultTmpDirByOS(),
                hadoopRPath = rxGetOption("unixRPath"),
                hadoopSwitches = "",
                revoPath = rxGetOption("unixRPath"),
                sshUsername = Sys.info()[["user"]],
                sshHostname = NULL,
                sshSwitches = "",
                sshProfileScript = NULL,
                sshClientDir = "",
                usingRunAsUserMode = FALSE,
                nameNode = rxGetOption("hdfsHost"),
                jobTrackerURL = NULL,
                port = rxGetOption("hdfsPort"),
                onClusterNode = NULL,
                wait = TRUE,
                consoleOutput = FALSE,
                showOutputWhileWaiting = TRUE,
                autoCleanup = TRUE,
                workingDir = NULL,
                dataPath = NULL,
                outDataPath = NULL,
                fileSystem = NULL,
                packagesToLoad = NULL,
                resultsTimeout = 15,
                ...  )

Arguments

`object`

object of class RxHadoopMR. This argument is optional. If supplied, the values of the other specified arguments are used to replace those of object and the modified object is returned.

`hdfsShareDir`

character string specifying the file sharing location within HDFS. You must have permissions to read and write to this location.

`shareDir`

character string specifying the directory on the master (perhaps edge) node that is shared among all the nodes of the cluster and any client host. You must have permissions to read and write in this directory.

`clientShareDir`

character string specifying the absolute path of the temporary directory on the client. Defaults to /tmp for POSIX-compliant non-Windows clients. For Windows and non-compliant POSIX clients, defaults to the value of the TEMP environment variable if defined, else to the TMP environment variable if defined, else to NULL. If the default directory does not exist, defaults to NULL. UNC paths ("\\host\dir") are not supported.

`hadoopRPath`

character string specifying the path to the directory on the cluster compute nodes containing the files R.exe and Rterm.exe. The invocation of R on each node must be identical.

`revoPath`

character string specifying the path to the directory on the master (perhaps edge) node containing the files R.exe and Rterm.exe.

`hadoopSwitches`

character string specifying optional generic Hadoop command line switches, for example -conf myconf.xml. See http://hadoop.apache.org/docs/current/hadoop-project-dist/hadoop-common/CommandsManual.html for details on the Hadoop command line generic options.

`sshUsername`

character string specifying the username for making an ssh connection to the Hadoop cluster. This is not needed if you are running your R client directly on the cluster. Defaults to the username of the user running the R client (that is, the value of Sys.info()[["user"]]).

`sshHostname`

character string specifying the hostname or IP address of the Hadoop cluster node or edge node that the client will log into for launching Hadoop jobs and for copying files between the client machine and the Hadoop cluster. Defaults to the hostname of the machine running the R client (that is, the value of Sys.info()[["nodename"]]) This field is only used if onClusterNode is NULL or FALSE. If you are using PuTTY on a Windows system, this can be the name of a saved PuTTY session that can include the user name and authentication file to use.

`sshSwitches`

character string specifying any switches needed for making an ssh connection to the Hadoop cluster. This is not needed if one is running one's R client directly on the cluster.

`sshProfileScript`

Optional character string specifying the absolute path to a profile script that will exists on the sshHostname host. This is used when the target ssh host does not automatically read in a .bash_profile, .profile or other shell environment configuration file for the definition of requisite variables such as HADOOP_STREAMING.

`sshClientDir`

character string specifying the Windows directory where Cygwin's ssh.exe and scp.exe or PuTTY's plink.exe and pscp.exe executables can be found. Needed only for Windows. Not needed if these executables are on the Windows Path or if Cygwin's location can be found in the Windows Registry. Defaults to the empty string.

`usingRunAsUserMode`

logical scalar specifying whether run-as-user mode is being used on the Hadoop cluster. When using run-as-user mode, local R processes started by the map-reduce framework will run as the same user that started the job, and will have any allocated local permissions. When not using run-as-user mode (the default for many Hadoop systems), local R processes will run as user mapred. Note that when running as user mapred, permissions for files and directories will have to be more open in order to allow hand-offs between the user and mapred. Run-as-user mode is controlled for the Hadoop map-reduce framework by the xml setting, mapred.task.tracker.task-controller, in the mapred-site.xml configuration file. If it is set to the value org.apache.hadoop.mapred.LinuxTaskController, then run-as-user mode is in use. If it is set to the value org.apache.hadoop.mapred.DefaultTaskController, then run-as-user mode is not in use.

`nameNode`

character string specifying the Hadoop name node hostname or IP address. Typically you can leave this at its default value. If set to a value other than "default" or the empty string (see below), this must be an address that can be resolved by the data nodes and used by them to contact the name node. Depending on your cluster, it may need to be set to a private network address such as "master.local". If set to the empty string, "", then the master process will set this to the name of the node on which it is running, as returned by Sys.info()[["nodename"]]. This is likely to work when the sshHostname points to the name node or the sshHostname is not specified and the R client is running on the name node. Defaults to rxGetOption("hdfsHost").

`jobTrackerURL`

character scalar specifying the full URL for the jobtracker web interface. This is used only for the purpose of loading the job tracker web page from the rxLaunchClusterJobManager convenience function. It is never used for job control, and its specification in the compute context is completely optional. See the rxLaunchClusterJobManager page for more information.

`port`

numeric scalar specifying the port used by the name node for hadoop jobs. Needs to be able to be cast to an integer. Defaults to rxGetOption("hdfsPort").

`onClusterNode`

logical scalar or NULL specifying whether the user is initiating the job from a client that will connect to either an edge node or an actual cluster node, directly from either an edge node or node within the cluster. If set to FALSE or NULL, then sshHostname must be a valid host.

`wait`

logical value. If TRUE, the job will be blocking and will not return until it has completed or has failed. If FALSE, the job will be non-blocking return immediately, allowing you to continue running other R code. The object rxgLastPendingJob is created with the job information. You can pass this object to the rxGetJobStatus function to check on the processing status of the job. rxWaitForJob will change a non-waiting job to a waiting job. Conversely, pressing ESC changes a waiting job to a non-waiting job, provided that the HPC scheduler has accepted the job. If you press ESC before the job has been accepted, the job is canceled.

`consoleOutput`

logical scalar. If TRUE, causes the standard output of the R processes to be printed to the user console.

`showOutputWhileWaiting`

logical scalar. If TRUE, causes the standard output of the remote primary R and hadoop job process to be printed to the user console while waiting for (blocking on) a job.

`autoCleanup`

logical scalar. If TRUE, the default behavior is to clean up the temporary computational artifacts and delete the result objects upon retrival. If FALSE, then the computational results are not deleted, and the results may be acquired using rxGetJobResults, and the output via rxGetJobOutput until the rxCleanupJobs is used to delete the results and other artifacts. Leaving this flag set to FALSE can result in accumulation of compute artifacts which you may eventually need to delete before they fill up your hard drive.

`workingDir`

character string specifying a working directory for the processes on the master node.

`dataPath`

NOT YET IMPLEMENTED. character vector defining the search path(s) for the data source(s).

`outDataPath`

NOT YET IMPLEMENTED. NULL or character vector defining the search path(s) for new output data file(s). If not NULL, this overrides any specification for outDataPath in rxOptions

`fileSystem`

NULL or an RxHdfsFileSystem to use as the default file system for data sources when created when this compute context is active.

`packagesToLoad`

optional character vector specifying additional packages to be loaded on the nodes when jobs are run in this compute context.

`resultsTimeout`

A numeric value indicating for how long attempts should be made to retrieve results from the cluster. Under normal conditions, results are available immediately. However, under certain high load conditions, the processes on the nodes have reported as completed, but the results have not been fully committed to disk by the operating system. Increase this parameter if results retrievial is failing on high load clusters.

`...`

additional arguments to be passed directly to the Microsoft R Services Compute Engine.

Details

This compute context is supported for Cloudera (CDH4 and CDH5), Hortonworks (HDP 1.3 and 2.x), and MapR (3.0.2, 3.0.3, 3.1.0, and 3.1.1) Hadoop distributions on Red Hat Enterprise Linux 5 and 6.

Value

object of class RxHadoopMR.

Examples


 ## Not run:

##############################################################################
# Run hadoop on edge node
##############################################################################

hadoopCC <- RxHadoopMR() 

##############################################################################    
# Run hadoop from a Windows client
# (requires Cygwin and/or PuTTY)
##############################################################################
mySshUsername <- "user1"
mySshHostname <- "12.345.678.90"  #public facing cluster IP address
mySshSwitches <- "-i /home/yourName/user1.pem" #use .ppk file with PuTTY
myShareDir <- paste("/var/RevoShare", mySshUsername, sep ="/")
myHdfsShareDir <- paste("/user/RevoShare", mySshUsername, sep="/")
myHadoopCluster <- RxHadoopMR(
hdfsShareDir = myHdfsShareDir,
shareDir = myShareDir,
sshUsername = mySshUsername,
sshHostname = mySshHostname,
sshSwitches = mySshSwitches)


## End(Not run)

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