##### 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 0.23.2 - Unreleased (as of 2018-09-01)

### INCOMPATIBLE CHANGES:

JIRA | Summary | Priority | Component | Reporter | Contributor
--- | --- | --- | --- | --- | ---
HDFS-2887 | Define a FSVolume interface | Major | datanode | Tsz Wo Nicholas Sze | Tsz Wo Nicholas Sze
HADOOP-8131 | FsShell put doesn’t correctly handle a non-existent dir | Critical | . | Daryn Sharp | Daryn Sharp
HADOOP-8164 | Handle paths using back slash as path separator for windows only | Major | fs | Suresh Srinivas | Daryn Sharp

### NEW FEATURES:

JIRA | Summary | Priority | Component | Reporter | Contributor
--- | --- | --- | --- | --- | ---
HDFS-2943 | Expose last checkpoint time and transaction stats as JMX metrics | Major | namenode | Aaron T. Myers | Aaron T. Myers

### IMPROVEMENTS:

JIRA | Summary | Priority | Component | Reporter | Contributor
--- | --- | --- | --- | --- | ---
HDFS-1217 | Some methods in the NameNdoe should not be public | Major | namenode | Tsz Wo Nicholas Sze | Laxman
HADOOP-8048 | Allow merging of Credentials | Major | util | Daryn Sharp | Daryn Sharp
HDFS-2506 | Umbrella jira for tracking separation of wire protocol datatypes from the implementation types | Major | datanode, namenode | Suresh Srinivas | Suresh Srinivas
HADOOP-8071 | Avoid an extra packet in client code when nagling is disabled | Minor | ipc | Todd Lipcon | Todd Lipcon
MAPREDUCE-3864 | Fix cluster setup docs for correct SNN HTTPS parameters | Minor | documentation, security | Todd Lipcon | Todd Lipcon
MAPREDUCE-3849 | Change TokenCache’s reading of the binary token file | Major | security | Daryn Sharp | Daryn Sharp
HDFS-2655 | BlockReaderLocal#skip performs unnecessary IO | Major | datanode | Eli Collins | Brandon Li
HDFS-2907 | Make FSDataset in Datanode Pluggable | Minor | . | Sanjay Radia | Tsz Wo Nicholas Sze
HDFS-2985 | Improve logging when replicas are marked as corrupt | Minor | namenode | Todd Lipcon | Todd Lipcon
HDFS-2981 | The default value of dfs.client.block.write.replace-datanode-on-failure.enable should be true | Major | . | Tsz Wo Nicholas Sze | Tsz Wo Nicholas Sze
MAPREDUCE-3730 | Allow restarted NM to rejoin cluster before RM expires it | Minor | mrv2, resourcemanager | Jason Lowe | Jason Lowe
MAPREDUCE-3901 | lazy load JobHistory Task and TaskAttempt details | Major | jobhistoryserver, mrv2 | Siddharth Seth | Siddharth Seth
MAPREDUCE-3922 | Fix the potential problem compiling 32 bit binaries on a x86_64 host. | Minor | build, mrv2 | Eugene Koontz | Hitesh Shah
HDFS-3024 | Improve performance of stringification in addStoredBlock | Minor | namenode | Todd Lipcon | Todd Lipcon
HDFS-3066 | cap space usage of default log4j rolling policy (hdfs specific changes) | Major | scripts | Patrick Hunt | Patrick Hunt
MAPREDUCE-3989 | cap space usage of default log4j rolling policy (mr specific changes) | Major | . | Patrick Hunt | Patrick Hunt

### BUG FIXES:

JIRA | Summary | Priority | Component | Reporter | Contributor
--- | --- | --- | --- | --- | ---
HADOOP-7874 | native libs should be under lib/native/ dir | Major | build | Alejandro Abdelnur | Alejandro Abdelnur
HADOOP-8042 | When copying a file out of HDFS, modifying it, and uploading it back into HDFS, the put fails due to a CRC mismatch | Critical | fs | Kevin J. Price | Daryn Sharp
HADOOP-8035 | Hadoop Maven site is inefficient and runs phases redundantly | Minor | build | Andrew Bayer | Andrew Bayer
HDFS-2764 | TestBackupNode is racy | Major | namenode, test | Aaron T. Myers | Aaron T. Myers
MAPREDUCE-3680 | FifoScheduler web service rest API can print out invalid JSON | Major | mrv2 | Thomas Graves |
HADOOP-8051 | HttpFS documentation it is not wired to the generated site | Major | documentation | Alejandro Abdelnur | Alejandro Abdelnur
MAPREDUCE-3852 | test TestLinuxResourceCalculatorPlugin failing | Blocker | mrv2 | Thomas Graves | Thomas Graves
HDFS-776 | Fix exception handling in Balancer | Critical | balancer & mover | Owen O’Malley | Uma Maheswara Rao G
HADOOP-6502 | DistributedFileSystem#listStatus is very slow when listing a directory with a size of 1300 | Critical | util | Hairong Kuang | Sharad Agarwal
HDFS-2950 | Secondary NN HTTPS address should be listed as a NAMESERVICE_SPECIFIC_KEY | Minor | namenode | Todd Lipcon | Todd Lipcon
HDFS-2525 | Race between BlockPoolSliceScanner and append | Critical | datanode | Todd Lipcon | Brandon Li
HDFS-2938 | Recursive delete of a large directory makes namenode unresponsive | Major | namenode | Suresh Srinivas | Hari Mankude
HADOOP-8074 | Small bug in hadoop error message for unknown commands | Trivial | scripts | Eli Collins | Colin P. McCabe
HADOOP-8082 | add hadoop-client and hadoop-minicluster to the dependency-management section | Major | build | Alejandro Abdelnur | Alejandro Abdelnur
HADOOP-8066 | The full docs build intermittently fails | Major | build | Aaron T. Myers | Andrew Bayer
HADOOP-8083 | javadoc generation for some modules is not done under target/ | Major | build | Alejandro Abdelnur | Alejandro Abdelnur
HADOOP-8036 | TestViewFsTrash assumes the user’s home directory is 2 levels deep | Major | fs, test | Eli Collins | Colin P. McCabe
MAPREDUCE-3862 | Nodemanager can appear to hang on shutdown due to lingering DeletionService threads | Major | mrv2, nodemanager | Jason Lowe | Jason Lowe
HDFS-2969 | ExtendedBlock.equals is incorrectly implemented | Critical | datanode | Todd Lipcon | Todd Lipcon
HADOOP-8046 | Revert StaticMapping semantics to the existing ones, add DNS mapping diagnostics in progress | Minor | . | Steve Loughran | Steve Loughran
HDFS-2725 | hdfs script usage information is missing the information about “dfs” command | Major | hdfs-client | Prashant Sharma |
HADOOP-8057 | hadoop-setup-conf.sh not working because of some extra spaces. | Major | scripts | Vinayakumar B | Vinayakumar B
MAPREDUCE-3634 | All daemons should crash instead of hanging around when their EventHandlers get exceptions | Major | mrv2 | Vinod Kumar Vavilapalli | Vinod Kumar Vavilapalli
HADOOP-8050 | Deadlock in metrics | Major | metrics | Kihwal Lee | Kihwal Lee
MAPREDUCE-3884 | PWD should be first in the classpath of MR tasks | Critical | mrv2 | Alejandro Abdelnur | Alejandro Abdelnur
HADOOP-7660 | Maven generated .classpath doesnot includes “target/generated-test-source/java” as source directory. | Minor | build | Laxman | Laxman
HDFS-2944 | Typo in hdfs-default.xml causes dfs.client.block.write.replace-datanode-on-failure.enable to be mistakenly disabled | Major | hdfs-client | Aaron T. Myers | Aaron T. Myers
MAPREDUCE-3878 | Null user on filtered jobhistory job page | Critical | mrv2 | Jonathan Eagles | Jonathan Eagles
MAPREDUCE-3583 | ProcfsBasedProcessTree#constructProcessInfo() may throw NumberFormatException | Critical | . | Ted Yu | Ted Yu
MAPREDUCE-3738 | NM can hang during shutdown if AppLogAggregatorImpl thread dies unexpectedly | Critical | mrv2, nodemanager | Jason Lowe | Jason Lowe
HDFS-3008 | Negative caching of local addrs doesn’t work | Major | hdfs-client | Eli Collins | Eli Collins
MAPREDUCE-3866 | bin/yarn prints the command line unnecessarily | Minor | mrv2 | Vinod Kumar Vavilapalli | Vinod Kumar Vavilapalli
MAPREDUCE-3904 | [NPE] Job history produced with mapreduce.cluster.acls.enabled false can not be viewed with mapreduce.cluster.acls.enabled true | Major | mrv2 | Jonathan Eagles | Jonathan Eagles
MAPREDUCE-3918 | proc_historyserver no longer in command line arguments for HistoryServer | Major | mrv2 | Jonathan Eagles | Jonathan Eagles
HDFS-3006 | Webhdfs “SETOWNER” call returns incorrect content-type | Major | webhdfs | bc Wong | Tsz Wo Nicholas Sze
MAPREDUCE-2793 | [MR-279] Maintain consistency in naming appIDs, jobIDs and attemptIDs | Critical | mrv2 | Ramya Sunil | Bikas Saha
MAPREDUCE-3910 | user not allowed to submit jobs even though queue -showacls shows it allows | Blocker | mrv2 | John George | John George
MAPREDUCE-3686 | history server web ui - job counter values for map/reduce not shown properly | Critical | mrv2 | Thomas Graves | Bhallamudi Venkata Siva Kamesh
MAPREDUCE-3913 | RM application webpage is unresponsive after 2000 jobs | Critical | mrv2, webapps | Jason Lowe | Jason Lowe
MAPREDUCE-2855 | ResourceBundle lookup during counter name resolution takes a lot of time | Major | . | Todd Lipcon | Siddharth Seth
MAPREDUCE-3790 | Broken pipe on streaming job can lead to truncated output for a successful job | Major | contrib/streaming, mrv2 | Jason Lowe | Jason Lowe
MAPREDUCE-3816 | capacity scheduler web ui bar graphs for used capacity wrong | Critical | mrv2 | Thomas Graves | Thomas Graves
MAPREDUCE-3930 | The AM page for a Reducer that has not been launched causes an NPE | Critical | mrv2 | Robert Joseph Evans | Robert Joseph Evans
MAPREDUCE-3931 | MR tasks failing due to changing timestamps on Resources to download | Major | mrv2 | Vinod Kumar Vavilapalli | Siddharth Seth
MAPREDUCE-3687 | If AM dies before it returns new tracking URL, proxy redirects to http://N/A/ and doesn’t return error code | Major | mrv2 | David Capwell | Ravi Prakash
MAPREDUCE-3920 | Revise yarn default port number selection | Major | nodemanager, resourcemanager | Dave Thompson | Dave Thompson
MAPREDUCE-3903 | no admin override to view jobs on mr app master and job history server | Critical | mrv2 | Thomas Graves | Thomas Graves
HDFS-3012 | Exception while renewing delegation token | Critical | . | Ramya Sunil | Robert Joseph Evans
MAPREDUCE-3706 | HTTP Circular redirect error on the job attempts page | Critical | mrv2 | Thomas Graves | Robert Joseph Evans
MAPREDUCE-3896 | pig job through oozie hangs | Blocker | jobhistoryserver, mrv2 | John George | Vinod Kumar Vavilapalli
MAPREDUCE-3792 | job -list displays only the jobs submitted by a particular user | Critical | mrv2 | Ramya Sunil | Jason Lowe
MAPREDUCE-3614 | finalState UNDEFINED if AM is killed by hand | Major | mrv2 | Ravi Prakash | Ravi Prakash
MAPREDUCE-3929 | output of mapred -showacl is not clear | Major | mrv2 | John George | John George
HADOOP-8123 | hadoop-project invalid pom warnings prevent transitive dependency resolution | Critical | build | Jonathan Eagles | Jonathan Eagles
MAPREDUCE-3960 | web proxy doesn’t forward request to AM with configured hostname/IP | Critical | mrv2 | Thomas Graves | Thomas Graves
MAPREDUCE-3897 | capacity scheduler - maxActiveApplicationsPerUser calculation can be wrong | Critical | mrv2 | Thomas Graves | Eric Payne
MAPREDUCE-3497 | missing documentation for yarn cli and subcommands - similar to commands_manual.html | Major | documentation, mrv2 | Thomas Graves | Thomas Graves
HADOOP-8137 | Site side links for commands manual (MAPREDUCE-3497) | Major | documentation | Vinod Kumar Vavilapalli | Thomas Graves
MAPREDUCE-3009 | RM UI -> Applications -> Application(Job History) -> Map Tasks -> Task ID -> Node link is not working | Major | jobhistoryserver, mrv2 | chackaravarthy | chackaravarthy
MAPREDUCE-3954 | Clean up passing HEAPSIZE to yarn and mapred commands. | Blocker | mrv2 | Robert Joseph Evans | Robert Joseph Evans
MAPREDUCE-3964 | ResourceManager does not have JVM metrics | Critical | mrv2, resourcemanager | Jason Lowe | Jason Lowe
HADOOP-8064 | Remove unnecessary dependency on w3c.org in document processing | Major | build | Kihwal Lee | Kihwal Lee
MAPREDUCE-3034 | NM should act on a REBOOT command from RM | Critical | mrv2, nodemanager | Vinod Kumar Vavilapalli | Devaraj K
HDFS-3032 | Lease renewer tries forever even if renewal is not possible | Major | hdfs-client | Kihwal Lee | Kihwal Lee
MAPREDUCE-3976 | TestRMContainerAllocator failing | Major | mrv2 | Bikas Saha | Jason Lowe
HADOOP-8140 | dfs -getmerge should process its argments better | Major | . | arkady borkovsky | Daryn Sharp
MAPREDUCE-3961 | Map/ReduceSlotMillis computation incorrect | Major | mrv2 | Siddharth Seth | Siddharth Seth
MAPREDUCE-3977 | LogAggregationService leaks log aggregator objects | Critical | mrv2, nodemanager | Jason Lowe | Jason Lowe
MAPREDUCE-3975 | Default value not set for Configuration parameter mapreduce.job.local.dir | Blocker | mrv2 | Eric Payne | Eric Payne
HADOOP-8146 | FsShell commands cannot be interrupted | Major | fs | Daryn Sharp | Daryn Sharp
MAPREDUCE-3982 | TestEmptyJob fails with FileNotFound | Critical | mrv2 | Robert Joseph Evans | Robert Joseph Evans
HDFS-3101 | cannot read empty file using webhdfs | Major | webhdfs | Zhanwei Wang | Tsz Wo Nicholas Sze
HADOOP-8176 | Disambiguate the destination of FsShell copies | Major | fs | Daryn Sharp | Daryn Sharp
MAPREDUCE-4005 | AM container logs URL is broken for completed apps when log aggregation is enabled | Major | mrv2 | Jason Lowe | Jason Lowe
MAPREDUCE-4006 | history server container log web UI sometimes combines stderr/stdout/syslog contents together | Major | jobhistoryserver, mrv2 | Jason Lowe | Siddharth Seth
MAPREDUCE-4025 | AM can crash if task attempt reports bogus progress value | Blocker | mr-am, mrv2 | Jason Lowe | Jason Lowe
MAPREDUCE-4034 | Unable to view task logs on history server with mapreduce.job.acl-view-job=* | Blocker | mrv2 | Jason Lowe | Jason Lowe
MAPREDUCE-4043 | Secret keys set in Credentials are not seen by tasks | Blocker | mrv2, security | Jason Lowe | Jason Lowe
MAPREDUCE-4061 | RM only has 1 AM launcher thread | Blocker | mrv2 | Thomas Graves | Thomas Graves
HDFS-3160 | httpfs should exec catalina instead of forking it | Major | scripts | Roman Shaposhnik | Roman Shaposhnik
HDFS-3853 | Port MiniDFSCluster enableManagedDfsDirsRedundancy option to branch-2 | Minor | namenode | Colin P. McCabe | Colin P. McCabe
HDFS-2815 | Namenode is not coming out of safemode when we perform ( NN crash + restart ) . Also FSCK report shows blocks missed. | Critical | namenode | Uma Maheswara Rao G | Uma Maheswara Rao G

### TESTS:

JIRA | Summary | Priority | Component | Reporter | Contributor
--- | --- | --- | --- | --- | ---
MAPREDUCE-3877 | Add a test to formalise the current state transitions of the yarn lifecycle | Minor | mrv2 | Steve Loughran | Steve Loughran
MAPREDUCE-3798 | TestJobCleanup testCustomCleanup is failing | Major | test | Ravi Prakash | Ravi Prakash
HDFS-3060 | Bump TestDistributedUpgrade#testDistributedUpgrade timeout | Minor | test | Eli Collins | Eli Collins
HDFS-2038 | Update test to handle relative paths with globs | Critical | test | Daryn Sharp | Kihwal Lee
HDFS-3098 | Update FsShell tests for quoted metachars | Major | test | Daryn Sharp | Daryn Sharp
HDFS-3104 | Add tests for mkdir -p | Major | test | Daryn Sharp | Daryn Sharp

### SUB-TASKS:

JIRA | Summary | Priority | Component | Reporter | Contributor
--- | --- | --- | --- | --- | ---
MAPREDUCE-3944 | JobHistory web services are slower then the UI and can easly overload the JH | Blocker | mrv2 | Robert Joseph Evans | Robert Joseph Evans
HADOOP-8173 | FsShell needs to handle quoted metachars | Major | fs | Daryn Sharp | Daryn Sharp
HADOOP-8175 | Add mkdir -p flag | Major | fs | Daryn Sharp | Daryn Sharp

### OTHER:

JIRA | Summary | Priority | Component | Reporter | Contributor
--- | --- | --- | --- | --- | ---
HADOOP-8032 | mvn site:stage-deploy should be able to use the scp protocol to stage documents | Major | build, documentation | Ravi Prakash | Ravi Prakash
HDFS-2931 | Switch the DataNode’s BlockVolumeChoosingPolicy to be a private-audience interface | Minor | datanode | Harsh J | Harsh J