[[repository-hdfs]]
=== Hadoop HDFS Repository Plugin

The HDFS repository plugin adds support for using HDFS File System as a repository for
{ref}/modules-snapshots.html[Snapshot/Restore].

:plugin_name: repository-hdfs
include::install_remove.asciidoc[]

[[repository-hdfs-usage]]
==== Getting started with HDFS

The HDFS snapshot/restore plugin is built against the latest Apache Hadoop 2.x (currently 2.7.1). If the distro you are using is not protocol
compatible with Apache Hadoop, consider replacing the Hadoop libraries inside the plugin folder with your own (you might have to adjust the security permissions required).

Even if Hadoop is already installed on the Elasticsearch nodes, for security reasons, the required libraries need to be placed under the plugin folder. Note that in most cases, if the distro is compatible, one simply needs to configure the repository with the appropriate Hadoop configuration files (see below).

Windows Users::
Using Apache Hadoop on Windows is problematic and thus it is not recommended. For those _really_ wanting to use it, make sure you place the elusive `winutils.exe` under the
plugin folder and point `HADOOP_HOME` variable to it; this should minimize the amount of permissions Hadoop requires (though one would still have to add some more).

[[repository-hdfs-config]]
==== Configuration Properties

Once installed, define the configuration for the `hdfs` repository through the
{ref}/modules-snapshots.html[REST API]:

[source,js]
----
PUT _snapshot/my_hdfs_repository
{
  "type": "hdfs",
  "settings": {
    "uri": "hdfs://namenode:8020/",
    "path": "elasticsearch/respositories/my_hdfs_repository",
    "conf.dfs.client.read.shortcircuit": "true"
  }
}
----
// CONSOLE
// TEST[skip:we don't have hdfs set up while testing this]

The following settings are supported:

[horizontal]
`uri`::

    The uri address for hdfs. ex: "hdfs://<host>:<port>/". (Required)

`path`::

    The file path within the filesystem where data is stored/loaded. ex: "path/to/file". (Required)

`load_defaults`::

    Whether to load the default Hadoop configuration or not. (Enabled by default)

`conf.<key>`::

    Inlined configuration parameter to be added to Hadoop configuration. (Optional)
    Only client oriented properties from the hadoop http://hadoop.apache.org/docs/current/hadoop-project-dist/hadoop-common/core-default.xml[core] and http://hadoop.apache.org/docs/current/hadoop-project-dist/hadoop-hdfs/hdfs-default.xml[hdfs] configuration files will be recognized by the plugin.

`compress`::

    Whether to compress the metadata or not. (Disabled by default)

`chunk_size`::

    Override the chunk size. (Disabled by default)

