~~ Licensed under the Apache License, Version 2.0 (the "License");
~~ you may not use this file except in compliance with the License.
~~ You may obtain a copy of the License at
~~
~~   http://www.apache.org/licenses/LICENSE-2.0
~~
~~ Unless required by applicable law or agreed to in writing, software
~~ distributed under the License is distributed on an "AS IS" BASIS,
~~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
~~ See the License for the specific language governing permissions and
~~ limitations under the License. See accompanying LICENSE file.

  ---
  Apache Hadoop ${project.version}
  ---
  ---
  ${maven.build.timestamp}
  
Apache Hadoop ${project.version}

  Apache Hadoop ${project.version} is a minor release in the 2.x.y release
  line, building upon the previous stable release 2.4.1.

  Here is a short overview of the major features and improvements.

  * {Common}

    * Authentication improvements when using an HTTP proxy server. This is
      useful when accessing WebHDFS via a proxy server.

    * A new Hadoop metrics sink that allows writing directly to Graphite.

    * {{{./hadoop-project-dist/hadoop-common/filesystem/index.html}Specification work}}
      related to the Hadoop Compatible Filesystem (HCFS) effort.

  * {HDFS}

    * Support for POSIX-style filesystem extended attributes. See the
      {{{./hadoop-project-dist/hadoop-hdfs/ExtendedAttributes.html}user documentation}}
      for more details.

    * Using the OfflineImageViewer, clients can now browse an fsimage via
      the WebHDFS API.

    * The NFS gateway received a number of supportability improvements and
      bug fixes. The Hadoop portmapper is no longer required to run the gateway,
      and the gateway is now able to reject connections from unprivileged ports.

    * The SecondaryNameNode, JournalNode, and DataNode web UIs have been
      modernized with HTML5 and Javascript.

  * {YARN}

    * YARN's REST APIs now support write/modify operations. Users can submit and
      kill applications through REST APIs.

    * The timeline store in YARN, used for storing generic and
      application-specific information for applications, supports authentication
      through Kerberos.

    * The Fair Scheduler supports dynamic hierarchical user queues, user queues
      are created dynamically at runtime under any specified parent-queue.

Getting Started

  The Hadoop documentation includes the information you need to get started using
  Hadoop. Begin with the
  {{{./hadoop-project-dist/hadoop-common/SingleCluster.html}Single Node Setup}} which
  shows you how to set up a single-node Hadoop installation. Then move on to the
  {{{./hadoop-project-dist/hadoop-common/ClusterSetup.html}Cluster Setup}} to learn how
  to set up a multi-node Hadoop installation.