##### 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 0.23.9 - 2013-07-08

### IMPROVEMENTS:

JIRA | Summary | Priority | Component | Reporter | Contributor
--- | --- | --- | --- | --- | ---
YARN-169 | Update log4j.appender.EventCounter to use org.apache.hadoop.log.metrics.EventCounter | Minor | nodemanager | Anthony Rojas | Anthony Rojas
MAPREDUCE-5268 | Improve history server startup performance | Major | jobhistoryserver | Jason Lowe | Karthik Kambatla

### BUG FIXES:

JIRA | Summary | Priority | Component | Reporter | Contributor
--- | --- | --- | --- | --- | ---
HDFS-4765 | Permission check of symlink deletion incorrectly throws UnresolvedLinkException | Major | namenode | Andrew Wang | Andrew Wang
YARN-742 | Log aggregation causes a lot of redundant setPermission calls | Major | nodemanager | Kihwal Lee | Jason Lowe
HDFS-4867 | metaSave NPEs when there are invalid blocks in repl queue. | Major | namenode | Kihwal Lee | Plamen Jeliazkov
HDFS-4862 | SafeModeInfo.isManual() returns true when resources are low even if it wasn’t entered into manually | Major | . | Ravi Prakash | Ravi Prakash
HDFS-4832 | Namenode doesn’t change the number of missing blocks in safemode when DNs rejoin or leave | Critical | . | Ravi Prakash | Ravi Prakash
HADOOP-9581 | hadoop –config non-existent directory should result in error | Major | scripts | Ashwin Shankar | Ashwin Shankar
MAPREDUCE-5308 | Shuffling to memory can get out-of-sync when fetching multiple compressed map outputs | Major | . | Nathan Roberts | Nathan Roberts
MAPREDUCE-5315 | DistCp reports success even on failure. | Critical | distcp | Mithun Radhakrishnan | Mithun Radhakrishnan
HDFS-4878 | On Remove Block, Block is not Removed from neededReplications queue | Major | namenode | Tao Luo | Tao Luo
MAPREDUCE-4019 | -list-attempt-ids is not working | Minor | client | B Anil Kumar | Ashwin Shankar
MAPREDUCE-5316 | job -list-attempt-ids command does not handle illegal task-state | Major | client | Ashwin Shankar | Ashwin Shankar
HADOOP-9582 | Non-existent file to “hadoop fs -conf” doesn’t throw error | Major | conf | Ashwin Shankar | Ashwin Shankar
HDFS-4205 | fsck fails with symlinks | Major | hdfs-client | Andy Isaacson | Jason Lowe

### TESTS:

JIRA | Summary | Priority | Component | Reporter | Contributor
--- | --- | --- | --- | --- | ---
MAPREDUCE-5084 | fix coverage org.apache.hadoop.mapreduce.v2.app.webapp and org.apache.hadoop.mapreduce.v2.hs.webapp | Major | . | Aleksey Gorshkov | Aleksey Gorshkov

### SUB-TASKS:

JIRA | Summary | Priority | Component | Reporter | Contributor
--- | --- | --- | --- | --- | ---
YARN-427 | Coverage fix for org.apache.hadoop.yarn.server.api.* | Major | . | Aleksey Gorshkov | Aleksey Gorshkov
YARN-478 | fix coverage org.apache.hadoop.yarn.webapp.log | Major | . | Aleksey Gorshkov | Aleksey Gorshkov