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Component family
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Big Data / Hadoop
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Function
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tHDFSDelete deletes a file
located on a given Hadoop distributed file system (HDFS).
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Purpose
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tHDFSDelete deletes a file on a
given HDFS.
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Basic settings
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Property type
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Either Built-in or Repository
Built-in: No property data stored
centrally.
Repository: Select the repository
file in which the properties are stored. The fields that follow are
completed automatically using the data retrieved.
Since version 5.6, both the Built-In mode and the Repository mode are
available in any of the Talend solutions.
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Use an existing connection
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Select this check box and in the Component List click the
HDFS connection component from which you want to reuse the connection details already
defined.
Note
When a Job contains the parent Job and the child Job, Component
list presents only the connection components in the same Job
level.
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Version
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Distribution
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Select the cluster you are using from the drop-down list. The options in the list vary
depending on the component you are using. Among these options, the following ones requires
specific configuration:
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If available in this Distribution drop-down list, the
Microsoft HD Insight option allows you to use a
Microsoft HD Insight cluster. For this purpose, you need to configure the
connections to the WebHCat service, the HD Insight service and the Windows Azure
Storage service of that cluster in the areas that are displayed. A demonstration
video about how to configure this connection is available in the following link:
https://www.youtube.com/watch?v=A3QTT6VsNoM
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The Custom option allows you to connect to a
cluster different from any of the distributions given in this list, that is to
say, to connect to a cluster not officially supported by Talend.
In order to connect to a custom distribution, once selecting Custom, click the  button to display the dialog box in which you can
alternatively:
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Select Import from existing version to import an
officially supported distribution as base and then add other required jar files
which the base distribution does not provide.
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Select Import from zip to import a custom
distribution zip that, for example, you can download from http://www.talendforge.org/exchange/index.php.
Note
In this dialog box, the active check box must be kept selected so as to import
the jar files pertinent to the connection to be created between the custom
distribution and this component.
For an step-by-step example about how to connect to a custom distribution and
share this connection, see Connecting to a custom Hadoop distribution.
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Hadoop version
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Select the version of the Hadoop distribution you are using. The available options vary
depending on the component you are using. Along with the evolution of Hadoop, please note
the following changes:
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If you use Hortonworks Data Platform V2.2, the
configuration files of your cluster might be using environment variables such as
${hdp.version}. If this is your situation, you
need to set the mapreduce.application.framework.path property in the Hadoop properties table of this component with the path value
explicitly pointing to the MapReduce framework archive of your cluster. For
example:
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mapreduce.application.framework.path=/hdp/apps/2.2.0.0-2041/mapreduce/mapreduce.tar.gz#mr-framework |
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If you use Hortonworks Data Platform V2.0.0, the
type of the operating system for running the distribution and a Talend
Job must be the same, such as Windows or Linux. Otherwise, you have to use Talend
Jobserver to execute the Job in the same type of operating system in which the
Hortonworks Data Platform V2.0.0 distribution you
are using is run. For further information about Talend Jobserver, see
Talend Installation
and Upgrade Guide.
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Authentication
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Use kerberos authentication
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If you are accessing the Hadoop cluster running with Kerberos security, select this check
box, then, enter the Kerberos principal name for the NameNode in the field displayed. This
enables you to use your user name to authenticate against the credentials stored in
Kerberos.
This check box is available depending on the Hadoop distribution you are connecting
to.
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Use a keytab to authenticate
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Select the Use a keytab to authenticate check box to log
into a Kerberos-enabled Hadoop system using a given keytab file. A keytab file contains
pairs of Kerberos principals and encrypted keys. You need to enter the principal to be used
in the Principal field and the access path to the keytab
file itself in the Keytab field.
Note that the user that executes a keytab-enabled Job is not necessarily the one a
principal designates but must have the right to read the keytab file being used. For
example, the user name you are using to execute a Job is user1 and the principal to be used is guest; in this situation, ensure that user1 has the right to read the keytab file to be used.
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NameNode URI
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Type in the URI of the Hadoop NameNode.
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User name
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User authentication name of HDFS.
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Group
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Enter the membership including the authentication user under which
the HDFS instances were started. This field is available depending
on the distribution you are using.
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File or Directory Path
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Browse to, or enter the path to the file or folder to be deleted
on HDFS.
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Advanced settings
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Hadoop properties
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If you need to use custom configuration for the Hadoop of
interest, complete this table with the property or properties to be
customized. Then at runtime, the customized property or properties
will override those corresponding ones defined earlier for the same
Hadoop.
For further information about the properties required by Hadoop,
see the Hadoop documentation.
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tStatCatcher Statistics
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Select this check box to collect log data at the component
level.
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Dynamic settings
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Click the [+] button to add a row in the table and fill the
Code field with a context variable to choose your HDFS
connection dynamically from multiple connections planned in your Job. This feature is useful
when you need to access files in different HDFS systems or different distributions,
especially when you are working in an environment where you cannot change your Job settings,
for example, when your Job has to be deployed and executed independent of Talend Studio.
The Dynamic settings table is available only when the
Use an existing connection check box is selected in the
Basic settings view. Once a dynamic parameter is
defined, the Component List box in the Basic settings view becomes unusable.
For more information on Dynamic settings and context
variables, see Talend Studio User Guide.
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Global Variables
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DELETE_PATH: the path to the deleted file or folder. This
is an After variable and it returns a string.
CURRENT_STATUS: the execution result of the component.
This is an After variable and it returns a string.
ERROR_MESSAGE: the error message generated by the
component when an error occurs. This is an After variable and it returns a string. This
variable functions only if the Die on error check box is
cleared, if the component has this check box.
A Flow variable functions during the execution of a component while an After variable
functions after the execution of the component.
To fill up a field or expression with a variable, press Ctrl +
Space to access the variable list and choose the variable to use from it.
For further information about variables, see Talend Studio
User Guide.
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Usage
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This component is used to compose a single-component Job or
Subjob.
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Prerequisites
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The Hadoop distribution must be properly installed, so as to guarantee the interaction
with Talend Studio. The following list presents MapR related information for
example.
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Ensure that you have installed the MapR client in the machine where the Studio is,
and added the MapR client library to the PATH variable of that machine. According
to MapR’s documentation, the library or libraries of a MapR client corresponding to
each OS version can be found under MAPR_INSTALL
hadoophadoop-VERSIONlib
ative. For example, the library for
Windows is lib
ativeMapRClient.dll in the MapR
client jar file. For further information, see the following link from MapR: http://www.mapr.com/blog/basic-notes-on-configuring-eclipse-as-a-hadoop-development-environment-for-mapr.
Without adding the specified library or libraries, you may encounter the following
error: no MapRClient in java.library.path.
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Set the -Djava.library.path argument, for example, in the Job Run VM arguments area
of the Run/Debug view in the [Preferences] dialog box. This argument provides to the Studio the
path to the native library of that MapR client. This allows the subscription-based
users to make full use of the Data viewer to view
locally in the Studio the data stored in MapR. For further information about how to
set this argument, see the section describing how to view data of Talend Big Data Getting Started Guide.
For further information about how to install a Hadoop distribution, see the manuals
corresponding to the Hadoop distribution you are using.
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Log4j
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The activity of this component can be logged using the log4j feature. For more information on this feature, see Talend Studio User
Guide.
For more information on the log4j logging levels, see the Apache documentation at http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/Level.html.
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Limitations
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JRE 1.6+ is required.
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