Description:

Retrieves a file from HDFS. The content of the incoming FlowFile is replaced by the content of the file in HDFS. The file in HDFS is left intact without any changes being made to it.

Tags:

hadoop, hdfs, get, ingest, fetch, source

Properties:

In the list below, the names of required properties appear in bold. Any other properties (not in bold) are considered optional. The table also indicates any default values, and whether a property supports the NiFi Expression Language.

NameDefault ValueAllowable ValuesDescription
Hadoop Configuration ResourcesA file or comma separated list of files which contains the Hadoop file system configuration. Without this, Hadoop will search the classpath for a 'core-site.xml' and 'hdfs-site.xml' file or will revert to a default configuration.
HDFS Filename${path}/${filename}The name of the HDFS file to retrieve
Supports Expression Language: true
Kerberos PrincipalKerberos principal to authenticate as. Requires nifi.kerberos.krb5.file to be set in your nifi.properties
Kerberos KeytabKerberos keytab associated with the principal. Requires nifi.kerberos.krb5.file to be set in your nifi.properties
Kerberos Relogin Period4 hoursPeriod of time which should pass before attempting a kerberos relogin

Relationships:

NameDescription
failureFlowFiles will be routed to this relationship if the content of the HDFS file cannot be retrieved and trying again will likely not be helpful. This would occur, for instance, if the file is not found or if there is a permissions issue
comms.failureFlowFiles will be routed to this relationship if the content of the HDFS file cannot be retrieve due to a communications failure. This generally indicates that the Fetch should be tried again.
successFlowFiles will be routed to this relationship once they have been updated with the content of the HDFS file

Reads Attributes:

None specified.

Writes Attributes:

NameDescription
hdfs.failure.reasonWhen a FlowFile is routed to 'failure', this attribute is added indicating why the file could not be fetched from HDFS

See Also:

ListHDFS, GetHDFS, PutHDFS