##### General

- Overview
- Single Node Setup
- Cluster Setup
- Commands Reference
- FileSystem Shell
- Compatibility Specification
- Downstream Developer's Guide
- Admin Compatibility Guide
- Interface Classification
- FileSystem Specification

##### Common

- CLI Mini Cluster
- Native Libraries
- Proxy User
- Rack Awareness
- Secure Mode
- Service Level Authorization
- HTTP Authentication
- Credential Provider API
- Hadoop KMS
- Tracing
- Unix Shell Guide

##### HDFS

- Architecture
- User Guide
- Commands Reference
- NameNode HA With QJM
- NameNode HA With NFS
- Observer NameNode
- Federation
- ViewFs
- ViewFsOverloadScheme
- Snapshots
- Edits Viewer
- Image Viewer
- Permissions and HDFS
- Quotas and HDFS
- libhdfs (C API)
- WebHDFS (REST API)
- HttpFS
- Short Circuit Local Reads
- Centralized Cache Management
- NFS Gateway
- Rolling Upgrade
- Extended Attributes
- Transparent Encryption
- Multihoming
- Storage Policies
- Memory Storage Support
- Synthetic Load Generator
- Erasure Coding
- Disk Balancer
- Upgrade Domain
- DataNode Admin
- Router Federation
- Provided Storage

##### MapReduce

- Tutorial
- Commands Reference
- Compatibility with 1.x
- Encrypted Shuffle
- Pluggable Shuffle/Sort
- Distributed Cache Deploy
- Support for YARN Shared Cache

##### MapReduce REST APIs

- MR Application Master
- MR History Server

##### YARN

- Architecture
- Commands Reference
- Capacity Scheduler
- Fair Scheduler
- ResourceManager Restart
- ResourceManager HA
- Resource Model
- Node Labels
- Node Attributes
- Web Application Proxy
- Timeline Server
- Timeline Service V.2
- Writing YARN Applications
- YARN Application Security
- NodeManager
- Running Applications in Docker Containers
- Using CGroups
- Secure Containers
- Registry
- Reservation System
- Graceful Decommission
- Opportunistic Containers
- YARN Federation
- Shared Cache
- Using GPU
- Using FPGA
- Placement Constraints
- YARN UI2

##### YARN REST APIs

- Introduction
- Resource Manager
- Node Manager
- Timeline Server
- Timeline Service V.2

##### YARN Service

- Overview
- QuickStart
- Concepts
- Yarn Service API
- Service Discovery
- System Services

##### Submarine

- Index
- QuickStart
- Examples

##### Hadoop Compatible File Systems

- Aliyun OSS
- Amazon S3
- Azure Blob Storage
- Azure Data Lake Storage
- OpenStack Swift

##### Auth

- Overview
- Examples
- Configuration
- Building

##### Tools

- Hadoop Streaming
- Hadoop Archives
- Hadoop Archive Logs
- DistCp
- GridMix
- Rumen
- Resource Estimator Service
- Scheduler Load Simulator
- Hadoop Benchmarking

##### Reference

- Changelog and Release Notes
- Java API docs
- Unix Shell API
- Metrics

##### Configuration

- core-default.xml
- hdfs-default.xml
- hdfs-rbf-default.xml
- mapred-default.xml
- yarn-default.xml
- kms-default.xml
- httpfs-default.xml
- Deprecated Properties

# Apache Hadoop Changelog

## Release 2.7.6 - 2018-04-16

### NEW FEATURES:

JIRA | Summary | Priority | Component | Reporter | Contributor
--- | --- | --- | --- | --- | ---
HADOOP-9477 | Add posixGroups support for LDAP groups mapping service | Major | . | Kai Zheng | Dapeng Sun

### IMPROVEMENTS:

JIRA | Summary | Priority | Component | Reporter | Contributor
--- | --- | --- | --- | --- | ---
HADOOP-12472 | Make GenericTestUtils.assertExceptionContains robust | Minor | test | Steve Loughran | Steve Loughran
HADOOP-12568 | Update core-default.xml to describe posixGroups support | Minor | documentation | Wei-Chiu Chuang | Wei-Chiu Chuang
HADOOP-13105 | Support timeouts in LDAP queries in LdapGroupsMapping. | Major | security | Chris Nauroth | Mingliang Liu
HADOOP-13263 | Reload cached groups in background after expiry | Major | . | Stephen O’Donnell | Stephen O’Donnell
HDFS-11003 | Expose “XmitsInProgress” through DataNodeMXBean | Major | . | Brahma Reddy Battula | Brahma Reddy Battula
HADOOP-14246 | Authentication Tokens should use SecureRandom instead of Random and 256 bit secrets | Major | security | Robert Kanter | Robert Kanter
YARN-7590 | Improve container-executor validation check | Major | security, yarn | Eric Yang | Eric Yang
HADOOP-15212 | Add independent secret manager method for logging expired tokens | Major | security | Daryn Sharp | Daryn Sharp
MAPREDUCE-7048 | Uber AM can crash due to unknown task in statusUpdate | Major | mr-am | Peter Bacsko | Peter Bacsko
HDFS-11187 | Optimize disk access for last partial chunk checksum of Finalized replica | Major | datanode | Wei-Chiu Chuang | Gabor Bota
HADOOP-15279 | increase maven heap size recommendations | Minor | build, documentation, test | Allen Wittenauer | Allen Wittenauer
HDFS-12884 | BlockUnderConstructionFeature.truncateBlock should be of type BlockInfo | Major | namenode | Konstantin Shvachko | chencan
HADOOP-15345 | Backport HADOOP-12185 to branch-2.7: NetworkTopology is not efficient adding/getting/removing nodes | Major | . | He Xiaoqiao | He Xiaoqiao

### BUG FIXES:

JIRA | Summary | Priority | Component | Reporter | Contributor
--- | --- | --- | --- | --- | ---
YARN-3425 | NPE from RMNodeLabelsManager.serviceStop when NodeLabelsManager.serviceInit failed | Minor | resourcemanager | Bibin A Chundatt | Bibin A Chundatt
HADOOP-12001 | Limiting LDAP search conflicts with posixGroup addition | Blocker | security | Patrick White | Patrick White
YARN-4167 | NPE on RMActiveServices#serviceStop when store is null | Minor | . | Bibin A Chundatt | Bibin A Chundatt
HADOOP-12181 | Fix intermittent test failure of TestZKSignerSecretProvider | Minor | . | Masatake Iwasaki | Masatake Iwasaki
HDFS-7959 | WebHdfs logging is missing on Datanode | Critical | . | Kihwal Lee | Kihwal Lee
HDFS-4210 | Throw helpful exception when DNS entry for JournalNode cannot be resolved | Trivial | ha, journal-node, namenode | Damien Hardy | John Zhuge
HADOOP-13375 | o.a.h.security.TestGroupsCaching.testBackgroundRefreshCounters seems flaky | Major | security, test | Mingliang Liu | Weiwei Yang
HADOOP-12611 | TestZKSignerSecretProvider#testMultipleInit occasionally fail | Major | . | Wei-Chiu Chuang | Eric Badger
HADOOP-13508 | FsPermission string constructor does not recognize sticky bit | Major | . | Atul Sikaria | Atul Sikaria
HDFS-12299 | Race Between update pipeline and DN Re-Registration | Critical | . | Brahma Reddy Battula | Brahma Reddy Battula
HDFS-12371 | “BlockVerificationFailures” and “BlocksVerified” show up as 0 in Datanode JMX | Major | metrics | Sai Nukavarapu | Hanisha Koneru
MAPREDUCE-5124 | AM lacks flow control for task events | Major | mr-am | Jason Lowe | Peter Bacsko
HDFS-12881 | Output streams closed with IOUtils suppressing write errors | Major | . | Jason Lowe | Ajay Kumar
YARN-7661 | NodeManager metrics return wrong value after update node resource | Major | . | Yang Wang | Yang Wang
HDFS-12347 | TestBalancerRPCDelay#testBalancerRPCDelay fails very frequently | Critical | test | Xiao Chen | Bharat Viswanadham
YARN-6632 | Backport YARN-3425 to branch 2.7 | Major | . | Íñigo Goiri | Íñigo Goiri
HADOOP-15143 | NPE due to Invalid KerberosTicket in UGI | Major | . | Jitendra Nath Pandey | Mukul Kumar Singh
MAPREDUCE-7028 | Concurrent task progress updates causing NPE in Application Master | Blocker | mr-am | Gergo Repas | Gergo Repas
HADOOP-12751 | While using kerberos Hadoop incorrectly assumes names with ‘@’ to be non-simple | Critical | security | Bolke de Bruin | Bolke de Bruin
MAPREDUCE-7020 | Task timeout in uber mode can crash AM | Major | mr-am | Akira Ajisaka | Peter Bacsko
HDFS-13126 | Backport [HDFS-7959] to branch-2.7 to re-enable HTTP request logging for WebHDFS | Major | datanode, webhdfs | Erik Krogen | Erik Krogen
HDFS-13120 | Snapshot diff could be corrupted after concat | Major | namenode, snapshots | Xiaoyu Yao | Xiaoyu Yao
HDFS-10453 | ReplicationMonitor thread could stuck for long time due to the race between replication and delete of same file in a large cluster. | Major | namenode | He Xiaoqiao | He Xiaoqiao
MAPREDUCE-7052 | TestFixedLengthInputFormat#testFormatCompressedIn is flaky | Major | client, test | Peter Bacsko | Peter Bacsko
HDFS-13112 | Token expiration edits may cause log corruption or deadlock | Critical | namenode | Daryn Sharp | Daryn Sharp
HADOOP-15206 | BZip2 drops and duplicates records when input split size is small | Major | . | Aki Tanaka | Aki Tanaka
HADOOP-15283 | Upgrade from findbugs 3.0.1 to spotbugs 3.1.2 in branch-2 to fix docker image build | Major | . | Xiao Chen | Akira Ajisaka
HDFS-13195 | DataNode conf page cannot display the current value after reconfig | Minor | datanode | maobaolong | maobaolong
HADOOP-12862 | LDAP Group Mapping over SSL can not specify trust store | Major | . | Wei-Chiu Chuang | Wei-Chiu Chuang
YARN-7249 | Fix CapacityScheduler NPE issue when a container preempted while the node is being removed | Blocker | . | Wangda Tan | Wangda Tan

### OTHER:

JIRA | Summary | Priority | Component | Reporter | Contributor
--- | --- | --- | --- | --- | ---
YARN-6633 | Backport YARN-4167 to branch 2.7 | Major | . | Íñigo Goiri | Íñigo Goiri
HADOOP-15177 | Update the release year to 2018 | Blocker | build | Akira Ajisaka | Bharat Viswanadham