[ANNOUNCE] Apache Hadoop 2.9.0 has been released

[Arun Suresh]

Hi all,

We are pleased to announce the release of Apache Hadoop 2.9.0. This is the
first release of Hadoop 2.9 line and will be the starting release for
Apache Hadoop 2.9.x line - it includes 30 New Features with 500+ subtasks,
407 Improvements, 790 Bug fixes new fixed issues since 2.8.2.

Please refer to the Apache Hadoop Release page [1] for download
instructions.

Major features include:
* Application Timeline Service v2 [2]
* YARN Federation [3]
* HDFS Router based Federation [4]
* Opportunistic Containers [5]
* YARN Web UI v2 [6]
* API for Scheduler Queue (Re-)configuration for CapacityScheduler [7]
* Container Update for CapacityScheduler [8]
* Hadoop Resource Estimator [9]

More details on all the features, subtasks and bug fixes can be found in
the change log [10] and release notes [11].

Although this release has been tested on fairly large clusters, production
users can wait for a subsequent point release which will contain fixes from
further stabilization and downstream adoption.

Thanks to all the many contributors who helped with this release!

Cheers
Subru and Arun

[1]: http://hadoop.apache.org/releases.html
[2]:
http://hadoop.apache.org/docs/r2.9.0/hadoop-yarn/hadoop-yarn-site/TimelineServiceV2.html
[3]:
http://hadoop.apache.org/docs/r2.9.0/hadoop-yarn/hadoop-yarn-site/Federation.html
[4]:
http://hadoop.apache.org/docs/r2.9.0/hadoop-project-dist/hadoop-hdfs/HDFSRouterFederation.html
[5]:
http://hadoop.apache.org/docs/r2.9.0/hadoop-yarn/hadoop-yarn-site/OpportunisticContainers.html
[6]:
http://hadoop.apache.org/docs/r2.9.0/hadoop-yarn/hadoop-yarn-site/YarnUI2.html
[7]:
http://hadoop.apache.org/docs/r2.9.0/hadoop-yarn/hadoop-yarn-site/CapacityScheduler.html#Changing_queue_configuration_via_API
[8]:
http://hadoop.apache.org/docs/r2.9.0/hadoop-yarn/hadoop-yarn-site/CapacityScheduler.html#Updating_a_Container_Experimental_-_API_may_change_in_the_future
[9]:
http://hadoop.apache.org/docs/r2.9.0/hadoop-resourceestimator/ResourceEstimator.html
[10]:
http://hadoop.apache.org/docs/r2.9.0/hadoop-project-dist/hadoop-common/release/2.9.0/CHANGES.2.9.0.html
[11]:
http://hadoop.apache.org/docs/r2.9.0/hadoop-project-dist/hadoop-common/release/2.9.0/RELEASENOTES.2.9.0.html