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| Licensed under the Apache License, Version 2.0 (the "License"); |
| you may not use this file except in compliance with the License. |
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| 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, |
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| |
| Apache Hadoop ${project.version} |
| ================================ |
| |
| Apache Hadoop ${project.version} is a point release in the 2.x.y release |
| line, building upon the previous stable release 2.8.4. |
| |
| Here is a short overview of the major features and improvements. |
| |
| * Common |
| |
| * Support async call retry and failover which can be used in async DFS |
| implementation with retry effort. |
| |
| * Cross Frame Scripting (XFS) prevention for UIs can be provided through |
| a common servlet filter. |
| |
| * S3A improvements: add ability to plug in any AWSCredentialsProvider, |
| support read s3a credentials from hadoop credential provider API in |
| addition to XML configuraiton files, support Amazon STS temporary |
| credentials |
| |
| * WASB improvements: adding append API support |
| |
| * Build enhancements: replace dev-support with wrappers to Yetus, |
| provide a docker based solution to setup a build environment, |
| remove CHANGES.txt and rework the change log and release notes. |
| |
| * Add posixGroups support for LDAP groups mapping service. |
| |
| * HDFS |
| |
| * WebHDFS enhancements: integrate CSRF prevention filter in WebHDFS, |
| support OAuth2 in WebHDFS, disallow/allow snapshots via WebHDFS |
| |
| * Allow long-running Balancer to login with keytab |
| |
| * Add ReverseXML processor which reconstructs an fsimage from an XML file. |
| This will make it easy to create fsimages for testing, and manually edit |
| fsimages when there is corruption |
| |
| * Support nested encryption zones |
| |
| * DataNode Lifeline Protocol: an alternative protocol for reporting DataNode |
| liveness. This can prevent the NameNode from incorrectly marking DataNodes |
| as stale or dead in highly overloaded clusters where heartbeat processing |
| is suffering delays. |
| |
| * Logging HDFS operation's caller context into audit logs |
| |
| * A new Datanode command for evicting writers which is useful when data node |
| decommissioning is blocked by slow writers. |
| |
| * YARN |
| |
| * NodeManager CPU resource monitoring in Windows. |
| |
| * NM shutdown more graceful: NM will unregister to RM immediately rather than |
| waiting for timeout to be LOST (if NM work preserving is not enabled). |
| |
| * Add ability to fail a specific AM attempt in scenario of AM attempt get stuck. |
| |
| * CallerContext support in YARN audit log. |
| |
| * ATS versioning support: a new configuration to indicate timeline service version. |
| |
| * MAPREDUCE |
| |
| * Allow node labels get specified in submitting MR jobs |
| |
| * Add a new tool to combine aggregated logs into HAR files |
| |
| 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. |
