Apache Hadoop 2.5.1
Apache Hadoop 2.5.1 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.
- 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.
- Specification work related to the Hadoop Compatible Filesystem (HCFS) effort.
- Support for POSIX-style filesystem extended attributes. See the 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.
- 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.
The Hadoop documentation includes the information you need to get started using Hadoop. Begin with the Single Node Setup which shows you how to set up a single-node Hadoop installation. Then move on to the Cluster Setup to learn how to set up a multi-node Hadoop installation.