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| |
| 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 2.9.2. |
| |
| Here is a short overview of the major features and improvements. |
| |
| * HDFS |
| |
| * Consistent reads from standby node. This allows better load balancing on HDFS |
| clusters, especially those with a high read/write operation ratio. See |
| [HDFS-12943](https://jira.apache.org/jira/browse/HDFS-12943) and |
| [HDFS-14204](https://jira.apache.org/jira/browse/HDFS-14204) for more details. |
| |
| * Improvements related to rolling upgrade support from 2.x to 3.x. |
| |
| * NameNode port based selective encryption. This allows enforcing different security |
| constraints for different types of traffic. See [HDFS-13541](https://issues.apache.org/jira/browse/HDFS-13541) |
| for more details. |
| |
| * Cost-based fair call queue. This improves fairness and stability in a large, multi-tenant |
| HDFS cluster. See [HDFS-14403](https://issues.apache.org/jira/browse/HDFS-14403) for more details. |
| |
| * YARN |
| |
| * Support for user-defined countable resource types beyond CPU and memory. This was |
| ported from the 3.x.y release line. See [YARN-3926](https://issues.apache.org/jira/browse/YARN-3926), |
| [YARN-8200](https://issues.apache.org/jira/browse/YARN-8200), |
| and the [YARN resource model documentation](./hadoop-yarn/hadoop-yarn-site/ResourceProfiles.html) for |
| more information. |
| |
| * Native support for GPUs as a schedulable resource type. This builds on the above, and was also ported |
| from the 3.x.y release line. See [YARN-6223](https://issues.apache.org/jira/browse/YARN-6223) and |
| [YARN-8200](https://issues.apache.org/jira/browse/YARN-8200) for more information. |
| |
| Getting Started |
| =============== |
| |
| The Hadoop documentation includes the information you need to get started using |
| Hadoop. Begin with the |
| [Single Node Setup](./hadoop-project-dist/hadoop-common/SingleCluster.html) which |
| shows you how to set up a single-node Hadoop installation. Then move on to the |
| [Cluster Setup](./hadoop-project-dist/hadoop-common/ClusterSetup.html) to learn how |
| to set up a multi-node Hadoop installation. |