##### 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 2.7.4 - 2017-08-04

### INCOMPATIBLE CHANGES:

JIRA | Summary | Priority | Component | Reporter | Contributor
--- | --- | --- | --- | --- | ---
HDFS-7933 | fsck should also report decommissioning replicas. | Major | namenode | Jitendra Nath Pandey | Xiaoyu Yao
HADOOP-13812 | Upgrade Tomcat to 6.0.48 | Blocker | kms | John Zhuge | John Zhuge
HADOOP-13119 | Add ability to secure log servlet using proxy users | Major | . | Jeffrey E Rodriguez | Yuanbo Liu
HADOOP-14138 | Remove S3A ref from META-INF service discovery, rely on existing core-default entry | Critical | fs/s3 | Steve Loughran | Steve Loughran

### NEW FEATURES:

JIRA | Summary | Priority | Component | Reporter | Contributor
--- | --- | --- | --- | --- | ---
HDFS-9804 | Allow long-running Balancer to login with keytab | Major | balancer & mover, security | Xiao Chen | Xiao Chen
MAPREDUCE-6304 | Specifying node labels when submitting MR jobs | Major | job submission | Jian Fang | Naganarasimha G R

### IMPROVEMENTS:

JIRA | Summary | Priority | Component | Reporter | Contributor
--- | --- | --- | --- | --- | ---
HDFS-8200 | Refactor FSDirStatAndListingOp | Major | . | Haohui Mai | Haohui Mai
HDFS-8131 | Implement a space balanced block placement policy | Minor | namenode | Liu Shaohui | Liu Shaohui
HDFS-8549 | Abort the balancer if an upgrade is in progress | Major | balancer & mover | Andrew Wang | Andrew Wang
HDFS-8709 | Clarify automatic sync in FSEditLog#logEdit | Minor | . | Andrew Wang | Andrew Wang
HADOOP-12259 | Utility to Dynamic port allocation | Major | test, util | Brahma Reddy Battula | Brahma Reddy Battula
HDFS-8883 | NameNode Metrics : Add FSNameSystem lock Queue Length | Major | namenode | Anu Engineer | Anu Engineer
HDFS-9019 | Adding informative message to sticky bit permission denied exception | Minor | security | Thejas M Nair | Xiaoyu Yao
HDFS-9145 | Tracking methods that hold FSNamesytemLock for too long | Major | namenode | Jing Zhao | Mingliang Liu
HDFS-9726 | Refactor IBR code to a new class | Minor | datanode | Tsz Wo Nicholas Sze | Tsz Wo Nicholas Sze
HADOOP-12668 | Support excluding weak Ciphers in HttpServer2 through ssl-server.xml | Critical | security | Vijay Singh | Vijay Singh
HDFS-9710 | Change DN to send block receipt IBRs in batches | Major | datanode | Tsz Wo Nicholas Sze | Tsz Wo Nicholas Sze
HDFS-9412 | getBlocks occupies FSLock and takes too long to complete | Major | balancer & mover, namenode | He Tianyi | He Tianyi
HDFS-9902 | Support different values of dfs.datanode.du.reserved per storage type | Major | datanode | Pan Yuxuan | Brahma Reddy Battula
HADOOP-13290 | Appropriate use of generics in FairCallQueue | Major | ipc | Konstantin Shvachko | Jonathan Hung
YARN-5483 | Optimize RMAppAttempt#pullJustFinishedContainers | Major | . | sandflee | sandflee
HDFS-10798 | Make the threshold of reporting FSNamesystem lock contention configurable | Major | logging, namenode | Zhe Zhang | Erik Krogen
HDFS-10807 | Doc about upgrading to a version of HDFS with snapshots may be confusing | Minor | documentation | Mingliang Liu | Mingliang Liu
HDFS-10625 | VolumeScanner to report why a block is found bad | Major | datanode, hdfs | Yongjun Zhang | Rushabh S Shah
YARN-5550 | TestYarnCLI#testGetContainers should format according to CONTAINER_PATTERN | Minor | client, test | Jonathan Hung | Jonathan Hung
HDFS-10817 | Add Logging for Long-held NN Read Locks | Major | logging, namenode | Erik Krogen | Erik Krogen
YARN-5540 | scheduler spends too much time looking at empty priorities | Major | capacity scheduler, fairscheduler, resourcemanager | Nathan Roberts | Jason Lowe
YARN-3877 | YarnClientImpl.submitApplication swallows exceptions | Minor | client | Steve Loughran | Varun Saxena
MAPREDUCE-6741 | add MR support to redact job conf properties | Major | mrv2 | Haibo Chen | Haibo Chen
HDFS-11069 | Tighten the authorization of datanode RPC | Major | datanode, security | Kihwal Lee | Kihwal Lee
HADOOP-12325 | RPC Metrics : Add the ability track and log slow RPCs | Major | ipc, metrics | Anu Engineer | Anu Engineer
HADOOP-13782 | Make MutableRates metrics thread-local write, aggregate-on-read | Major | metrics | Erik Krogen | Erik Krogen
HDFS-10941 | Improve BlockManager#processMisReplicatesAsync log | Major | namenode | Xiaoyu Yao | Chen Liang
HADOOP-13742 | Expose “NumOpenConnectionsPerUser” as a metric | Major | . | Brahma Reddy Battula | Brahma Reddy Battula
HDFS-10534 | NameNode WebUI should display DataNode usage histogram | Major | namenode, ui | Zhe Zhang | Kai Sasaki
HDFS-11333 | Print a user friendly error message when plugins are not found | Minor | namenode | Wei-Chiu Chuang | Wei-Chiu Chuang
HDFS-11466 | Change dfs.namenode.write-lock-reporting-threshold-ms default from 1000ms to 5000ms | Major | namenode | Andrew Wang | Andrew Wang
HADOOP-14169 | Implement listStatusIterator, listLocatedStatus for ViewFs | Minor | viewfs | Erik Krogen | Erik Krogen
HDFS-11628 | Clarify the behavior of HDFS Mover in documentation | Major | documentation | Xiaobing Zhou | Xiaobing Zhou
HADOOP-14276 | Add a nanosecond API to Time/Timer/FakeTimer | Minor | util | Erik Krogen | Erik Krogen
HDFS-11648 | Lazy construct the IIP pathname | Major | . | Daryn Sharp | Daryn Sharp
HDFS-11634 | Optimize BlockIterator when iterating starts in the middle. | Major | . | Konstantin Shvachko | Konstantin Shvachko
HDFS-11384 | Add option for balancer to disperse getBlocks calls to avoid NameNode’s rpc.CallQueueLength spike | Major | balancer & mover | yunjiong zhao | Konstantin Shvachko
HDFS-8873 | Allow the directoryScanner to be rate-limited | Major | datanode | Nathan Roberts | Daniel Templeton
YARN-6457 | Allow custom SSL configuration to be supplied in WebApps | Major | webapp, yarn | Sanjay M Pujare | Sanjay M Pujare
YARN-6493 | Print requested node partition in assignContainer logs | Major | . | Jonathan Hung | Jonathan Hung
HADOOP-14440 | Add metrics for connections dropped | Major | . | Eric Badger | Eric Badger
HDFS-11345 | Document the configuration key for FSNamesystem lock fairness | Minor | documentation, namenode | Zhe Zhang | Erik Krogen

### BUG FIXES:

JIRA | Summary | Priority | Component | Reporter | Contributor
--- | --- | --- | --- | --- | ---
HADOOP-7851 | Configuration.getClasses() never returns the default value. | Major | conf | Amar Kamat | Uma Maheswara Rao G
YARN-1471 | The SLS simulator is not running the preemption policy for CapacityScheduler | Minor | . | Carlo Curino | Carlo Curino
HADOOP-11703 | git should ignore .DS_Store files on Mac OS X | Major | . | Abin Shahab | Abin Shahab
YARN-3269 | Yarn.nodemanager.remote-app-log-dir could not be configured to fully qualified path | Major | . | Xuan Gong | Xuan Gong
HDFS-7990 | IBR delete ack should not be delayed | Major | namenode | Daryn Sharp | Daryn Sharp
HADOOP-11859 | PseudoAuthenticationHandler fails with httpcomponents v4.4 | Major | . | Eugene Koifman | Eugene Koifman
HDFS-7847 | Modify NNThroughputBenchmark to be able to operate on a remote NameNode | Major | . | Colin P. McCabe | Charles Lamb
HDFS-6291 | FSImage may be left unclosed in BootstrapStandby#doRun() | Minor | ha | Ted Yu | Sanghyun Yun
YARN-3707 | RM Web UI queue filter doesn’t work | Blocker | . | Wangda Tan | Wangda Tan
HADOOP-12173 | NetworkTopology#add calls NetworkTopology#toString always | Major | . | Íñigo Goiri | Íñigo Goiri
HDFS-8682 | Should not remove decommissioned node,while calculating the number of live/dead decommissioned node. | Major | . | J.Andreina | J.Andreina
HDFS-5802 | NameNode does not check for inode type before traversing down a path | Trivial | namenode | Harsh J | Xiao Chen
YARN-4017 | container-executor overuses PATH_MAX | Major | nodemanager | Allen Wittenauer | Sidharta Seethana
YARN-4250 | NPE in AppSchedulingInfo#isRequestLabelChanged | Major | resourcemanager, scheduler | Brahma Reddy Battula | Brahma Reddy Battula
HADOOP-12483 | Maintain wrapped SASL ordering for postponed IPC responses | Critical | ipc | Daryn Sharp | Daryn Sharp
HADOOP-12418 | TestRPC.testRPCInterruptedSimple fails intermittently | Major | test | Steve Loughran | Kihwal Lee
YARN-4302 | SLS not able start due to NPE in SchedulerApplicationAttempt#getResourceUsageReport | Major | . | Bibin A Chundatt | Bibin A Chundatt
YARN-4367 | SLS webapp doesn’t load | Major | scheduler-load-simulator | Karthik Kambatla | Karthik Kambatla
HADOOP-11149 | Increase the timeout of TestZKFailoverController | Major | test | Rajat Jain | Steve Loughran
HDFS-9467 | Fix data race accessing writeLockHeldTimeStamp in FSNamesystem | Major | namenode | Mingliang Liu | Mingliang Liu
YARN-4109 | Exception on RM scheduler page loading with labels | Minor | . | Bibin A Chundatt | Mohammad Shahid Khan
YARN-4612 | Fix rumen and scheduler load simulator handle killed tasks properly | Major | . | Ming Ma | Ming Ma
YARN-4927 | TestRMHA#testTransitionedToActiveRefreshFail fails with FairScheduler | Major | test | Karthik Kambatla | Bibin A Chundatt
YARN-4562 | YARN WebApp ignores the configuration passed to it for keystore settings | Major | . | Sergey Shelukhin | Sergey Shelukhin
HDFS-10270 | TestJMXGet:testNameNode() fails | Minor | test | Andras Bokor | Gergely Novák
HADOOP-13026 | Should not wrap IOExceptions into a AuthenticationException in KerberosAuthenticator | Critical | . | Xuan Gong | Xuan Gong
HDFS-10276 | HDFS should not expose path info that user has no permission to see. | Major | fs, security | Kevin Cox | Yuanbo Liu
YARN-5197 | RM leaks containers if running container disappears from node update | Critical | resourcemanager | Jason Lowe | Jason Lowe
YARN-5262 | Optimize sending RMNodeFinishedContainersPulledByAMEvent for every AM heartbeat | Major | resourcemanager | Rohith Sharma K S | Rohith Sharma K S
HDFS-10396 | Using -diff option with DistCp may get “Comparison method violates its general contract” exception | Major | . | Yongjun Zhang | Yongjun Zhang
HDFS-10336 | TestBalancer failing intermittently because of not reseting UserGroupInformation completely | Major | test | Yiqun Lin | Yiqun Lin
HDFS-10512 | VolumeScanner may terminate due to NPE in DataNode.reportBadBlocks | Major | datanode | Wei-Chiu Chuang | Yiqun Lin
YARN-5353 | ResourceManager can leak delegation tokens when they are shared across apps | Critical | resourcemanager | Jason Lowe | Jason Lowe
HADOOP-11361 | Fix a race condition in MetricsSourceAdapter.updateJmxCache | Major | . | Brahma Reddy Battula | Brahma Reddy Battula
HDFS-10544 | Balancer doesn’t work with IPFailoverProxyProvider | Major | balancer & mover, ha | Zhe Zhang | Zhe Zhang
HADOOP-13202 | Avoid possible overflow in org.apache.hadoop.util.bloom.BloomFilter#getNBytes | Major | util | zhengbing li | Kai Sasaki
HADOOP-12991 | Conflicting default ports in DelegateToFileSystem | Major | fs | Kevin Hogeland | Kai Sasaki
MAPREDUCE-6744 | Increase timeout on TestDFSIO tests | Major | . | Eric Badger | Eric Badger
HDFS-10691 | FileDistribution fails in hdfs oiv command due to ArrayIndexOutOfBoundsException | Major | . | Yiqun Lin | Yiqun Lin
YARN-5121 | fix some container-executor portability issues | Blocker | nodemanager, security | Allen Wittenauer | Allen Wittenauer
MAPREDUCE-6724 | Single shuffle to memory must not exceed Integer#MAX_VALUE | Major | mrv2 | Haibo Chen | Haibo Chen
HDFS-8780 | Fetching live/dead datanode list with arg true for removeDecommissionNode,returns list with decom node. | Major | . | J.Andreina | J.Andreina
YARN-5462 | TestNodeStatusUpdater.testNodeStatusUpdaterRetryAndNMShutdown fails intermittently | Major | . | Eric Badger | Eric Badger
YARN-5469 | Increase timeout of TestAmFilter.testFilter | Minor | . | Eric Badger | Eric Badger
HDFS-10716 | In Balancer, the target task should be removed when its size < 0. | Minor | balancer & mover | Yiqun Lin | Yiqun Lin
HDFS-10715 | NPE when applying AvailableSpaceBlockPlacementPolicy | Major | namenode | Guangbin Zhu | Guangbin Zhu
YARN-5333 | Some recovered apps are put into default queue when RM HA | Major | . | Jun Gong | Jun Gong
HDFS-10693 | metaSave should print blocks, not LightWeightHashSet | Major | namenode | Konstantin Shvachko | Yuanbo Liu
HDFS-10694 | BlockManager.processReport() should print blockReportId in each log message. | Major | logging, namenode | Konstantin Shvachko | Yuanbo Liu
HDFS-8224 | Schedule a block for scanning if its metadata file is corrupt | Major | datanode | Rushabh S Shah | Rushabh S Shah
YARN-5382 | RM does not audit log kill request for active applications | Major | resourcemanager | Jason Lowe | Vrushali C
HDFS-9696 | Garbage snapshot records lingering forever | Critical | . | Kihwal Lee | Kihwal Lee
HDFS-10747 | o.a.h.hdfs.tools.DebugAdmin usage message is misleading | Minor | hdfs-client | Mingliang Liu | Mingliang Liu
HADOOP-13494 | ReconfigurableBase can log sensitive information | Major | security | Sean Mackrory | Sean Mackrory
HADOOP-13512 | ReloadingX509TrustManager should keep reloading in case of exception | Critical | security | Mingliang Liu | Mingliang Liu
HDFS-10763 | Open files can leak permanently due to inconsistent lease update | Critical | . | Kihwal Lee | Kihwal Lee
MAPREDUCE-6763 | Shuffle server listen queue is too small | Major | mrv2 | Jason Lowe | Jason Lowe
HDFS-8312 | Trash does not descent into child directories to check for permissions | Critical | fs, security | Eric Yang | Weiwei Yang
HDFS-8915 | TestFSNamesystem.testFSLockGetWaiterCount fails intermittently in jenkins | Minor | test | Anu Engineer | Masatake Iwasaki
HADOOP-12765 | HttpServer2 should switch to using the non-blocking SslSelectChannelConnector to prevent performance degradation when handling SSL connections | Major | . | Min Shen | Min Shen
MAPREDUCE-6768 | TestRecovery.testSpeculative failed with NPE | Major | mrv2 | Haibo Chen | Haibo Chen
MAPREDUCE-4784 | TestRecovery occasionally fails | Major | mrv2, test | Jason Lowe | Haibo Chen
HDFS-10809 | getNumEncryptionZones causes NPE in branch-2.7 | Major | encryption, namenode | Zhe Zhang | Vinitha Reddy Gankidi
HADOOP-13558 | UserGroupInformation created from a Subject incorrectly tries to renew the Kerberos ticket | Major | security | Alejandro Abdelnur | Xiao Chen
HDFS-9038 | DFS reserved space is erroneously counted towards non-DFS used. | Major | datanode | Chris Nauroth | Brahma Reddy Battula
HADOOP-13579 | Fix source-level compatibility after HADOOP-11252 | Blocker | . | Akira Ajisaka | Tsuyoshi Ozawa
HADOOP-13601 | Fix typo in a log messages of AbstractDelegationTokenSecretManager | Trivial | . | Mehran Hassani | Mehran Hassani
HDFS-10879 | TestEncryptionZonesWithKMS#testReadWrite fails intermittently | Major | . | Xiao Chen | Xiao Chen
HDFS-10843 | Update space quota when a UC block is completed rather than committed. | Major | hdfs, namenode | Erik Krogen | Erik Krogen
HADOOP-13535 | Add jetty6 acceptor startup issue workaround to branch-2 | Major | . | Wei-Chiu Chuang | Min Shen
HADOOP-12597 | In kms-site.xml configuration “hadoop.security.keystore.JavaKeyStoreProvider.password” should be updated with new name | Minor | security | huangyitian | Surendra Singh Lilhore
HDFS-9885 | Correct the distcp counters name while displaying counters | Minor | distcp | Archana T | Surendra Singh Lilhore
HDFS-10889 | Remove outdated Fault Injection Framework documentaion | Major | documentation | Brahma Reddy Battula | Brahma Reddy Battula
HDFS-10713 | Throttle FsNameSystem lock warnings | Major | logging, namenode | Arpit Agarwal | Hanisha Koneru
HDFS-10915 | Fix time measurement bug in TestDatanodeRestart#testWaitForRegistrationOnRestart | Minor | test | Xiaobing Zhou | Xiaobing Zhou
HDFS-9444 | Add utility to find set of available ephemeral ports to ServerSocketUtil | Major | . | Brahma Reddy Battula | Masatake Iwasaki
HADOOP-11780 | Prevent IPC reader thread death | Critical | ipc | Daryn Sharp | Daryn Sharp
MAPREDUCE-6771 | RMContainerAllocator sends container diagnostics event after corresponding completion event | Major | mrv2 | Haibo Chen | Haibo Chen
HDFS-10878 | TestDFSClientRetries#testIdempotentAllocateBlockAndClose throws ConcurrentModificationException | Major | hdfs-client | Rushabh S Shah | Rushabh S Shah
HDFS-10609 | Uncaught InvalidEncryptionKeyException during pipeline recovery may abort downstream applications | Major | encryption | Wei-Chiu Chuang | Wei-Chiu Chuang
HDFS-10991 | Export hdfsTruncateFile symbol in libhdfs | Blocker | libhdfs | Surendra Singh Lilhore | Surendra Singh Lilhore
HDFS-11002 | Fix broken attr/getfattr/setfattr links in ExtendedAttributes.md | Major | documentation | Mingliang Liu | Mingliang Liu
HDFS-10987 | Make Decommission less expensive when lot of blocks present. | Critical | . | Brahma Reddy Battula | Brahma Reddy Battula
HDFS-10301 | BlockReport retransmissions may lead to storages falsely being declared zombie if storage report processing happens out of order | Critical | namenode | Konstantin Shvachko | Vinitha Reddy Gankidi
HDFS-10712 | Fix TestDataNodeVolumeFailure on 2.* branches. | Major | . | Konstantin Shvachko | Vinitha Reddy Gankidi
HDFS-10627 | Volume Scanner marks a block as “suspect” even if the exception is network-related | Major | hdfs | Rushabh S Shah | Rushabh S Shah
HADOOP-13236 | truncate will fail when we use viewfilesystem | Major | . | Brahma Reddy Battula | Brahma Reddy Battula
HDFS-11015 | Enforce timeout in balancer | Major | balancer & mover | Kihwal Lee | Kihwal Lee
HDFS-11053 | Unnecessary superuser check in versionRequest() | Major | namenode, security | Kihwal Lee | Kihwal Lee
HDFS-10921 | TestDiskspaceQuotaUpdate doesn’t wait for NN to get out of safe mode | Major | . | Eric Badger | Eric Badger
HADOOP-13201 | Print the directory paths when ViewFs denies the rename operation on internal dirs | Major | viewfs | Tianyin Xu | Rakesh R
YARN-4328 | Findbugs warning in resourcemanager in branch-2.7 and branch-2.6 | Minor | resourcemanager | Varun Saxena | Akira Ajisaka
YARN-3432 | Cluster metrics have wrong Total Memory when there is reserved memory on CS | Major | capacityscheduler, resourcemanager | Thomas Graves | Brahma Reddy Battula
HDFS-9500 | datanodesSoftwareVersions map may counting wrong when rolling upgrade | Major | . | Phil Yang | Erik Krogen
HDFS-10455 | Logging the username when deny the setOwner operation | Minor | namenode | Tianyin Xu | Rakesh R
YARN-5001 | Aggregated Logs root directory is created with wrong group if nonexistent | Major | log-aggregation, nodemanager, security | Haibo Chen | Haibo Chen
YARN-5837 | NPE when getting node status of a decommissioned node after an RM restart | Major | . | Robert Kanter | Robert Kanter
HADOOP-13804 | MutableStat mean loses accuracy if add(long, long) is used | Minor | metrics | Erik Krogen | Erik Krogen
HDFS-8307 | Spurious DNS Queries from hdfs shell | Trivial | hdfs-client | Anu Engineer | Andres Perez
HDFS-11087 | NamenodeFsck should check if the output writer is still writable. | Major | namenode | Konstantin Shvachko | Erik Krogen
HDFS-11056 | Concurrent append and read operations lead to checksum error | Major | datanode, httpfs | Wei-Chiu Chuang | Wei-Chiu Chuang
YARN-4355 | NPE while processing localizer heartbeat | Major | nodemanager | Jason Lowe | Varun Saxena
HDFS-10966 | Enhance Dispatcher logic on deciding when to give up a source DataNode | Major | balancer & mover | Zhe Zhang | Mark Wagner
HDFS-11174 | Wrong HttpFS test command in doc | Minor | documentation, httpfs | John Zhuge | John Zhuge
YARN-5694 | ZKRMStateStore can prevent the transition to standby in branch-2.7 if the ZK node is unreachable | Critical | resourcemanager | Daniel Templeton | Daniel Templeton
HDFS-11180 | Intermittent deadlock in NameNode when failover happens. | Blocker | namenode | Abhishek Modi | Akira Ajisaka
HADOOP-13867 | FilterFileSystem should override rename(.., options) to take effect of Rename options called via FilterFileSystem implementations | Major | . | Vinayakumar B | Vinayakumar B
HDFS-11229 | HDFS-11056 failed to close meta file | Blocker | datanode | Wei-Chiu Chuang | Wei-Chiu Chuang
HDFS-11160 | VolumeScanner reports write-in-progress replicas as corrupt incorrectly | Major | datanode | Wei-Chiu Chuang | Wei-Chiu Chuang
HDFS-11263 | ClassCastException when we use Bzipcodec for Fsimage compression | Critical | . | Brahma Reddy Battula | Brahma Reddy Battula
YARN-6024 | Capacity Scheduler ‘continuous reservation looking’ doesn’t work when sum of queue’s used and reserved resources is equal to max | Major | . | Wangda Tan | Wangda Tan
YARN-5988 | RM unable to start in secure setup | Blocker | . | Ajith S | Ajith S
HADOOP-13839 | Fix outdated tracing documentation | Minor | documentation, tracing | Masatake Iwasaki | Elek, Marton
HDFS-11280 | Allow WebHDFS to reuse HTTP connections to NN | Major | hdfs | Zheng Shao | Zheng Shao
MAPREDUCE-6711 | JobImpl fails to handle preemption events on state COMMITTING | Major | . | Li Lu | Prabhu Joseph
HADOOP-13958 | Bump up release year to 2017 | Blocker | . | Junping Du | Junping Du
HDFS-10733 | NameNode terminated after full GC thinking QJM is unresponsive. | Major | namenode, qjm | Konstantin Shvachko | Vinitha Reddy Gankidi
HADOOP-14001 | Improve delegation token validity checking | Major | . | Akira Ajisaka | Akira Ajisaka
HDFS-11352 | Potential deadlock in NN when failing over | Critical | namenode | Erik Krogen | Erik Krogen
HADOOP-14044 | Synchronization issue in delegation token cancel functionality | Major | . | Hrishikesh Gadre | Hrishikesh Gadre
HDFS-11377 | Balancer hung due to no available mover threads | Major | balancer & mover | yunjiong zhao | yunjiong zhao
YARN-6152 | Used queue percentage not accurate in UI for 2.7 and below when using DominantResourceCalculator | Major | . | Jonathan Hung | Jonathan Hung
HADOOP-13433 | Race in UGI.reloginFromKeytab | Major | security | Duo Zhang | Duo Zhang
HDFS-11379 | DFSInputStream may infinite loop requesting block locations | Critical | hdfs-client | Daryn Sharp | Daryn Sharp
YARN-1728 | Workaround guice3x-undecoded pathInfo in YARN WebApp | Major | . | Abraham Elmahrek | Yuanbo Liu
YARN-6310 | OutputStreams in AggregatedLogFormat.LogWriter can be left open upon exceptions | Major | yarn | Haibo Chen | Haibo Chen
HDFS-11499 | Decommissioning stuck because of failing recovery | Major | hdfs, namenode | Lukas Majercak | Lukas Majercak
HADOOP-9631 | ViewFs should use underlying FileSystem’s server side defaults | Major | fs, viewfs | Lohit Vijayarenu | Erik Krogen
HADOOP-14214 | DomainSocketWatcher::add()/delete() should not self interrupt while looping await() | Critical | hdfs-client | Mingliang Liu | Mingliang Liu
HADOOP-14195 | CredentialProviderFactory$getProviders is not thread-safe | Major | security | Vihang Karajgaonkar | Vihang Karajgaonkar
HADOOP-14211 | FilterFs and ChRootedFs are too aggressive about enforcing “authorityNeeded” | Major | viewfs | Erik Krogen | Erik Krogen
HDFS-11486 | Client close() should not fail fast if the last block is being decommissioned | Major | . | Wei-Chiu Chuang | Wei-Chiu Chuang
HADOOP-13362 | DefaultMetricsSystem leaks the source name when a source unregisters | Blocker | metrics | Jason Lowe | Junping Du
MAPREDUCE-6873 | MR Job Submission Fails if MR framework application path not on defaultFS | Minor | mrv2 | Erik Krogen | Erik Krogen
HDFS-11608 | HDFS write crashed with block size greater than 2 GB | Critical | hdfs-client | Xiaobing Zhou | Xiaobing Zhou
HADOOP-14066 | VersionInfo should be marked as public API | Critical | common | Thejas M Nair | Akira Ajisaka
HADOOP-14293 | Initialize FakeTimer with a less trivial value | Major | test | Andrew Wang | Andrew Wang
YARN-6304 | Skip rm.transitionToActive call to RM if RM is already active. | Major | resourcemanager | Rohith Sharma K S | Rohith Sharma K S
HDFS-11615 | FSNamesystemLock metrics can be inaccurate due to millisecond precision | Major | hdfs | Erik Krogen | Erik Krogen
HDFS-11709 | StandbyCheckpointer should handle an non-existing legacyOivImageDir gracefully | Critical | ha, namenode | Zhe Zhang | Erik Krogen
HDFS-11609 | Some blocks can be permanently lost if nodes are decommissioned while dead | Blocker | namenode | Kihwal Lee | Kihwal Lee
HDFS-8498 | Blocks can be committed with wrong size | Critical | hdfs-client | Daryn Sharp | Jing Zhao
HDFS-11714 | Newly added NN storage directory won’t get initialized and cause space exhaustion | Critical | . | Kihwal Lee | Kihwal Lee
HADOOP-14371 | License error in TestLoadBalancingKMSClientProvider.java | Major | . | hu xiaodong | hu xiaodong
HADOOP-14374 | License error in GridmixTestUtils.java | Major | . | lixinglong | lixinglong
HDFS-11766 | Fix findbugs warning in branch-2.7 | Major | . | Akira Ajisaka | Chen Liang
HADOOP-14100 | Upgrade Jsch jar to latest version to fix vulnerability in old versions | Critical | . | Vinayakumar B | Vinayakumar B
HDFS-11373 | Backport HDFS-11258 and HDFS-11272 to branch-2.7 | Critical | . | Akira Ajisaka | Akira Ajisaka
HDFS-11795 | Fix ASF Licence warnings in branch-2.7 | Major | . | Yiqun Lin | Yiqun Lin
YARN-5543 | ResourceManager SchedulingMonitor could potentially terminate the preemption checker thread | Major | capacityscheduler, resourcemanager | Min Shen | Min Shen
HDFS-11674 | reserveSpaceForReplicas is not released if append request failed due to mirror down and replica recovered | Critical | datanode | Vinayakumar B | Vinayakumar B
HADOOP-14376 | Memory leak when reading a compressed file using the native library | Major | common, io | Eli Acherkan | Eli Acherkan
HADOOP-14434 | Use MoveFileEx to allow renaming a file when the destination exists | Major | native | Lukas Majercak | Lukas Majercak
HDFS-11849 | JournalNode startup failure exception should be logged in log file | Major | journal-node | Surendra Singh Lilhore | Surendra Singh Lilhore
HDFS-11864 | Document Metrics to track usage of memory for writes | Major | documentation | Brahma Reddy Battula | Yiqun Lin
YARN-6615 | AmIpFilter drops query parameters on redirect | Major | . | Wilfred Spiegelenburg | Wilfred Spiegelenburg
HDFS-11445 | FSCK shows overall health status as corrupt even one replica is corrupt | Critical | . | Brahma Reddy Battula | Brahma Reddy Battula
HDFS-11078 | Fix NPE in LazyPersistFileScrubber | Major | . | Íñigo Goiri | Íñigo Goiri
HDFS-5042 | Completed files lost after power failure | Critical | . | Dave Latham | Vinayakumar B
HDFS-11893 | Fix TestDFSShell.testMoveWithTargetPortEmpty failure. | Major | test | Konstantin Shvachko | Brahma Reddy Battula
HDFS-11741 | Long running balancer may fail due to expired DataEncryptionKey | Major | balancer & mover | Wei-Chiu Chuang | Wei-Chiu Chuang
HDFS-11856 | Ability to re-add Upgrading Nodes (remote) to pipeline for future pipeline updates | Major | hdfs-client, rolling upgrades | Vinayakumar B | Vinayakumar B
HADOOP-14474 | Use OpenJDK 7 instead of Oracle JDK 7 to avoid oracle-java7-installer failures | Major | build | Akira Ajisaka | Akira Ajisaka
YARN-4925 | ContainerRequest in AMRMClient, application should be able to specify nodes/racks together with nodeLabelExpression | Major | . | Bibin A Chundatt | Bibin A Chundatt
HDFS-11708 | Positional read will fail if replicas moved to different DNs after stream is opened | Critical | hdfs-client | Vinayakumar B | Vinayakumar B
HDFS-11743 | Revert the incompatible fsck reporting output in HDFS-7933 from branch-2.7 | Blocker | namenode | Zhe Zhang | Zhe Zhang
HDFS-11583 | Parent spans are not initialized to NullScope for every DFSPacket | Major | tracing | Karan Mehta | Masatake Iwasaki
YARN-6719 | Fix findbugs warnings in SLSCapacityScheduler.java | Major | . | Akira Ajisaka | Akira Ajisaka
HDFS-11736 | OIV tests should not write outside ‘target’ directory. | Major | . | Konstantin Shvachko | Yiqun Lin
MAPREDUCE-6433 | launchTime may be negative | Major | jobhistoryserver, mrv2 | Allen Wittenauer | zhihai xu
HADOOP-10829 | Iteration on CredentialProviderFactory.serviceLoader is thread-unsafe | Major | security | Benoy Antony | Benoy Antony
HADOOP-14586 | StringIndexOutOfBoundsException breaks org.apache.hadoop.util.Shell on 2.7.x with Java 9 | Minor | common | Uwe Schindler | Akira Ajisaka
MAPREDUCE-6697 | Concurrent task limits should only be applied when necessary | Major | mrv2 | Jason Lowe | Nathan Roberts
YARN-3260 | AM attempt fail to register before RM processes launch event | Critical | resourcemanager | Jason Lowe | Bibin A Chundatt
YARN-6818 | User limit per partition is not honored in branch-2.7 >= | Major | . | Jonathan Hung | Jonathan Hung
HADOOP-14356 | Update CHANGES.txt to reflect all the changes in branch-2.7 | Blocker | . | Brahma Reddy Battula | Brahma Reddy Battula
HDFS-11472 | Fix inconsistent replica size after a data pipeline failure | Critical | datanode | Wei-Chiu Chuang | Erik Krogen
HDFS-12177 | NameNode exits due to setting BlockPlacementPolicy loglevel to Debug | Major | block placement | Jiandan Yang | Jiandan Yang
HDFS-11742 | Improve balancer usability after HDFS-8818 | Blocker | . | Kihwal Lee | Kihwal Lee
HADOOP-14686 | Branch-2.7 .gitignore is out of date | Blocker | build, precommit | Sean Busbey | Sean Busbey
HDFS-11896 | Non-dfsUsed will be doubled on dead node re-registration | Blocker | . | Brahma Reddy Battula | Brahma Reddy Battula

### TESTS:

JIRA | Summary | Priority | Component | Reporter | Contributor
--- | --- | --- | --- | --- | ---
HDFS-9888 | Allow reseting KerberosName in unit tests | Minor | . | Xiao Chen | Xiao Chen
YARN-4717 | TestResourceLocalizationService.testPublicResourceInitializesLocalDir fails Intermittently due to IllegalArgumentException from cleanup | Minor | nodemanager | Daniel Templeton | Daniel Templeton
YARN-5092 | TestRMDelegationTokens fails intermittently | Major | test | Rohith Sharma K S | Jason Lowe
HADOOP-10980 | TestActiveStandbyElector fails occasionally in trunk | Minor | . | Ted Yu | Eric Badger
HDFS-9745 | TestSecureNNWithQJM#testSecureMode sometimes fails with timeouts | Minor | . | Xiao Chen | Xiao Chen
HDFS-9333 | Some tests using MiniDFSCluster errored complaining port in use | Minor | test | Kai Zheng | Masatake Iwasaki
HDFS-11290 | TestFSNameSystemMBean should wait until JMX cache is cleared | Major | test | Akira Ajisaka | Erik Krogen

### SUB-TASKS:

JIRA | Summary | Priority | Component | Reporter | Contributor
--- | --- | --- | --- | --- | ---
HDFS-8721 | Add a metric for number of encryption zones | Major | encryption | Rakesh R | Rakesh R
HDFS-8824 | Do not use small blocks for balancing the cluster | Major | balancer & mover | Tsz Wo Nicholas Sze | Tsz Wo Nicholas Sze
HDFS-9421 | NNThroughputBenchmark replication test NPE with -namenode option | Major | benchmarks | Xiaoyu Yao | Mingliang Liu
YARN-4393 | TestResourceLocalizationService#testFailedDirsResourceRelease fails intermittently | Major | test | Varun Saxena | Varun Saxena
HDFS-9621 | getListing wrongly associates Erasure Coding policy to pre-existing replicated files under an EC directory | Critical | erasure-coding | Sushmitha Sreenivasan | Jing Zhao
HDFS-9601 | NNThroughputBenchmark.BlockReportStats should handle NotReplicatedYetException on adding block | Major | test | Masatake Iwasaki | Masatake Iwasaki
YARN-4573 | TestRMAppTransitions.testAppRunningKill and testAppKilledKilled fail on trunk | Major | resourcemanager, test | Takashi Ohnishi | Takashi Ohnishi
HDFS-9503 | Replace -namenode option with -fs for NNThroughputBenchmark | Major | test | Konstantin Shvachko | Mingliang Liu
HADOOP-12975 | Add jitter to CachingGetSpaceUsed’s thread | Major | . | Elliott Clark | Elliott Clark
HDFS-10653 | Optimize conversion from path string to components | Major | hdfs | Daryn Sharp | Daryn Sharp
HDFS-10656 | Optimize conversion of byte arrays back to path string | Major | hdfs | Daryn Sharp | Daryn Sharp
HDFS-10674 | Optimize creating a full path from an inode | Major | hdfs | Daryn Sharp | Daryn Sharp
HDFS-10655 | Fix path related byte array conversion bugs | Major | hdfs | Daryn Sharp | Daryn Sharp
HDFS-10662 | Optimize UTF8 string/byte conversions | Major | hdfs | Daryn Sharp | Daryn Sharp
HDFS-10673 | Optimize FSPermissionChecker’s internal path usage | Major | hdfs | Daryn Sharp | Daryn Sharp
HDFS-10744 | Internally optimize path component resolution | Major | hdfs | Daryn Sharp | Daryn Sharp
HDFS-10619 | Cache path in InodesInPath | Major | hdfs | Daryn Sharp | Daryn Sharp
HDFS-10896 | Move lock logging logic from FSNamesystem into FSNamesystemLock | Major | namenode | Erik Krogen | Erik Krogen
HDFS-10745 | Directly resolve paths into INodesInPath | Major | hdfs | Daryn Sharp | Daryn Sharp
HADOOP-10597 | RPC Server signals backoff to clients when all request queues are full | Major | . | Ming Ma | Ming Ma
HADOOP-10300 | Allowed deferred sending of call responses | Major | ipc | Daryn Sharp | Daryn Sharp
HDFS-10872 | Add MutableRate metrics for FSNamesystemLock operations | Major | namenode | Erik Krogen | Erik Krogen
HADOOP-13655 | document object store use with fs shell and distcp | Major | documentation, fs, fs/s3 | Steve Loughran | Steve Loughran
HDFS-8818 | Allow Balancer to run faster | Major | balancer & mover | Tsz Wo Nicholas Sze | Tsz Wo Nicholas Sze
YARN-4140 | RM container allocation delayed incase of app submitted to Nodelabel partition | Major | scheduler | Bibin A Chundatt | Bibin A Chundatt

### OTHER:

JIRA | Summary | Priority | Component | Reporter | Contributor
--- | --- | --- | --- | --- | ---
HADOOP-13670 | Update CHANGES.txt to reflect all the changes in branch-2.7 | Blocker | . | Brahma Reddy Battula | Brahma Reddy Battula
YARN-6274 | Documentation refers to incorrect nodemanager health checker interval property | Trivial | documentation | Charles Zhang | Weiwei Yang
HDFS-11717 | Add unit test for HDFS-11709 StandbyCheckpointer should handle non-existing legacyOivImageDir gracefully | Minor | ha, namenode | Erik Krogen | Erik Krogen