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Apache HDFS Connection
======================

The Apache HDFS connection type enables connection to Apache HDFS.

Default Connection IDs
----------------------

HDFS Hook uses parameter ``hdfs_conn_id`` for Connection IDs and the value of the parameter
as ``hdfs_default`` by default.
Web HDFS Hook uses parameter ``webhdfs_conn_id`` for Connection IDs and the value of the
parameter as ``webhdfs_default`` by default.

Configuring the Connection
--------------------------
Host
    The host to connect to, it can be ``local``, ``yarn`` or an URL. For Web HDFS Hook it is possible to specify multiple hosts as a comma-separated list.

Port
    Specify the port in case of host be an URL.

Login
    Effective user for HDFS operations (non-Kerberized).

Extra (optional, connection parameters)
    Specify the extra parameters (as json dictionary) that can be used in HDFS connection. The following
    parameters out of the standard python parameters are supported:

    * ``autoconfig`` - Default value is bool: False. Use snakebite's automatically configured client. This HDFSHook implementation requires snakebite.
    * ``hdfs_namenode_principal`` - Specifies the Kerberos principal to use for HDFS.

    The following extra parameters can be used to configure SSL for Web HDFS Hook:

    * ``use_ssl`` - If SSL should be used. By default is set to `false`.
    * ``verify`` - How to verify SSL. For more information refer to https://docs.python-requests.org/en/master/user/advanced/#ssl-cert-verification.