##### 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 1.2.1 - 2013-08-01

### IMPROVEMENTS:

JIRA | Summary | Priority | Component | Reporter | Contributor
--- | --- | --- | --- | --- | ---
MAPREDUCE-4838 | Add extra info to JH files | Major | . | Arun C Murthy | Zhijie Shen
MAPREDUCE-5368 | Save memory by set capacity, load factor and concurrency level for ConcurrentHashMap in TaskInProgress | Major | mrv1 | yunjiong zhao | yunjiong zhao

### BUG FIXES:

JIRA | Summary | Priority | Component | Reporter | Contributor
--- | --- | --- | --- | --- | ---
HDFS-4581 | DataNode#checkDiskError should not be called on network errors | Major | datanode | Rohit Kochar | Rohit Kochar
HDFS-4699 | TestPipelinesFailover#testPipelineRecoveryStress fails sporadically | Major | test | Chris Nauroth | Chris Nauroth
MAPREDUCE-5206 | JT can show the same job multiple times in Retired Jobs section | Minor | . | Arun C Murthy | Arun C Murthy
MAPREDUCE-5148 | Syslog missing from Map/Reduce tasks | Major | tasktracker | Yesha Vora | Arun C Murthy
MAPREDUCE-3859 | CapacityScheduler incorrectly utilizes extra-resources of queue for high-memory jobs | Major | capacity-sched | Sergey Tryuber | Sergey Tryuber
HDFS-4261 | TestBalancerWithNodeGroup times out | Major | balancer & mover | Tsz Wo Nicholas Sze | Junping Du
HDFS-4880 | Diagnostic logging while loading name/edits files | Major | namenode | Arpit Agarwal | Suresh Srinivas
MAPREDUCE-5260 | Job failed because of JvmManager running into inconsistent state | Major | tasktracker | yunjiong zhao | yunjiong zhao
MAPREDUCE-5318 | Ampersand in JSPUtil.java is not escaped | Minor | jobtracker | Bohou Li | Bohou Li
HADOOP-9665 | BlockDecompressorStream#decompress will throw EOFException instead of return -1 when EOF | Critical | . | Zhijie Shen | Zhijie Shen
MAPREDUCE-5375 | Delegation Token renewal exception in jobtracker logs | Critical | . | Venkat Ranganathan | Venkat Ranganathan
HADOOP-9504 | MetricsDynamicMBeanBase has concurrency issues in createMBeanInfo | Critical | metrics | Liang Xie | Liang Xie
MAPREDUCE-5256 | CombineInputFormat isn’t thread safe affecting HiveServer | Major | . | Vinod Kumar Vavilapalli | Vinod Kumar Vavilapalli
MAPREDUCE-5351 | JobTracker memory leak caused by CleanupQueue reopening FileSystem | Critical | jobtracker | Sandy Ryza | Sandy Ryza
MAPREDUCE-5364 | Deadlock between RenewalTimerTask methods cancel() and run() | Major | . | Karthik Kambatla | Karthik Kambatla
HADOOP-9730 | fix hadoop.spec to add task-log4j.properties | Major | build | Giridharan Kesavan | Giridharan Kesavan
MAPREDUCE-4490 | JVM reuse is incompatible with LinuxTaskController (and therefore incompatible with Security) | Critical | task-controller, tasktracker | George Datskos | sam liu

### OTHER:

JIRA | Summary | Priority | Component | Reporter | Contributor
--- | --- | --- | --- | --- | ---
HADOOP-10371 | The eclipse-plugin cannot work in my environment | Minor | contrib/eclipse-plugin | huangxing |