Hadoop 2.7.2 Release Notes

• YARN-4434. Minor bug reported by Takashi Ohnishi and fixed by Weiwei Yang (documentation , nodemanager)
  NodeManager Disk Checker parameter documentation is not correct
  

• YARN-4424. Blocker bug reported by Yesha Vora and fixed by Jian He
  Fix deadlock in RMAppImpl
  

• YARN-4365. Major bug reported by Jason Lowe and fixed by Kuhu Shukla (resourcemanager)
  FileSystemNodeLabelStore should check for root dir existence on startup
  

• YARN-4354. Blocker bug reported by Jason Lowe and fixed by Jason Lowe (nodemanager)
  Public resource localization fails with NPE
  

• YARN-4348. Blocker bug reported by Tsuyoshi Ozawa and fixed by Tsuyoshi Ozawa
  ZKRMStateStore.syncInternal shouldn't wait for sync completion for avoiding blocking ZK's event thread
  

• YARN-4344. Critical bug reported by Varun Vasudev and fixed by Varun Vasudev (resourcemanager)
  NMs reconnecting with changed capabilities can lead to wrong cluster resource calculations
  

• YARN-4326. Major bug reported by MENG DING and fixed by MENG DING
  Fix TestDistributedShell timeout as AHS in MiniYarnCluster no longer binds to default port 8188
  

• YARN-4321. Major bug reported by Varun Saxena and fixed by Varun Saxena (resourcemanager)
  Incessant retries if NoAuthException is thrown by Zookeeper in non HA mode
  

• YARN-4320. Major bug reported by Varun Saxena and fixed by Varun Saxena
  TestJobHistoryEventHandler fails as AHS in MiniYarnCluster no longer binds to default port 8188
  

• YARN-4313. Major bug reported by Jian He and fixed by Jian He
  Race condition in MiniMRYarnCluster when getting history server address
  

• YARN-4312. Major bug reported by Varun Saxena and fixed by Varun Saxena
  TestSubmitApplicationWithRMHA fails on branch-2.7 and branch-2.6 as some of the test cases time out
  

• YARN-4281. Blocker bug reported by Chang Li and fixed by Chang Li
  2.7 RM app page is broken
  

• YARN-4241. Major bug reported by Anthony Rojas and fixed by Anthony Rojas (documentation)
  Fix typo of property name in yarn-default.xml
  

• YARN-4209. Critical bug reported by zhihai xu and fixed by zhihai xu (resourcemanager)
  RMStateStore FENCED state doesn’t work due to updateFencedState called by stateMachine.doTransition
  

• YARN-4180. Critical bug reported by Anubhav Dhoot and fixed by Anubhav Dhoot (resourcemanager)
  AMLauncher does not retry on failures when talking to NM
  

• YARN-4158. Minor improvement reported by zhihai xu and fixed by zhihai xu (nodemanager)
  Remove duplicate close for LogWriter in AppLogAggregatorImpl#uploadLogsForContainers
  

• YARN-4127. Major bug reported by Jian He and fixed by Varun Saxena (resourcemanager)
  RM fail with noAuth error if switched from failover mode to non-failover mode
  

• YARN-4105. Major bug reported by Chang Li and fixed by Chang Li (capacityscheduler)
  Capacity Scheduler headroom for DRF is wrong
  

• YARN-4103. Major bug reported by Jonathan Eagles and fixed by Jonathan Eagles
  RM WebServices missing scheme for appattempts logLinks
  

• YARN-4101. Critical sub-task reported by Yesha Vora and fixed by Xuan Gong (yarn)
  RM should print alert messages if Zookeeper and Resourcemanager gets connection issue
  

• YARN-4096. Major bug reported by Jason Lowe and fixed by Jason Lowe (log-aggregation , nodemanager)
  App local logs are leaked if log aggregation fails to initialize for the app
  

• YARN-4092. Major sub-task reported by Xuan Gong and fixed by Xuan Gong (resourcemanager)
  RM HA UI redirection needs to be fixed when both RMs are in standby mode
  

• YARN-4087. Major bug reported by Jian He and fixed by Jian He
  Followup fixes after YARN-2019 regarding RM behavior when state-store error occurs
  

• YARN-4047. Major bug reported by Jason Lowe and fixed by Jason Lowe (resourcemanager)
  ClientRMService getApplications has high scheduler lock contention
  

• YARN-4041. Major bug reported by Jason Lowe and fixed by Sunil G (resourcemanager)
  Slow delegation token renewal can severely prolong RM recovery
  

• YARN-4009. Major bug reported by Prakash Ramachandran and fixed by Varun Vasudev
  CORS support for ResourceManager REST API
  

• YARN-4005. Major bug reported by Jun Gong and fixed by Jun Gong
  Completed container whose app is finished is not removed from NMStateStore
  

• YARN-4000. Major bug reported by Jason Lowe and fixed by Varun Saxena (capacityscheduler , resourcemanager)
  RM crashes with NPE if leaf queue becomes parent queue during restart
  

• YARN-3999. Major bug reported by Jian He and fixed by Jian He
  RM hangs on draining events
  

• YARN-3990. Critical bug reported by Rohith Sharma K S and fixed by Bibin A Chundatt (resourcemanager)
  AsyncDispatcher may overloaded with RMAppNodeUpdateEvent when Node is connected/disconnected
  

• YARN-3978. Major improvement reported by Eric Payne and fixed by Eric Payne (timelineserver , yarn)
  Configurably turn off the saving of container info in Generic AHS
  

• YARN-3975. Major bug reported by Mit Desai and fixed by Mit Desai
  WebAppProxyServlet should not redirect to RM page if AHS is enabled
  

• YARN-3969. Major sub-task reported by Subru Krishnan and fixed by Subru Krishnan (capacityscheduler , fairscheduler , resourcemanager)
  Allow jobs to be submitted to reservation that is active but does not have any allocations
  

• YARN-3967. Major bug reported by Mit Desai and fixed by Mit Desai
  Fetch the application report from the AHS if the RM does not know about it
  

• YARN-3925. Critical bug reported by zhihai xu and fixed by zhihai xu (nodemanager)
  ContainerLogsUtils#getContainerLogFile fails to read container log files from full disks.
  

• YARN-3905. Major bug reported by Eric Payne and fixed by Eric Payne (timelineserver)
  Application History Server UI NPEs when accessing apps run after RM restart
  

• YARN-3896. Major bug reported by Jun Gong and fixed by Jun Gong (resourcemanager)
  RMNode transitioned from RUNNING to REBOOTED because its response id had not been reset synchronously
  

• YARN-3893. Critical sub-task reported by Bibin A Chundatt and fixed by Bibin A Chundatt (resourcemanager)
  Both RM in active state when Admin#transitionToActive failure from refeshAll()
  

• YARN-3878. Critical bug reported by Varun Saxena and fixed by Varun Saxena
  AsyncDispatcher can hang while stopping if it is configured for draining events on stop
  

• YARN-3857. Critical bug reported by mujunchao and fixed by mujunchao (resourcemanager)
  Memory leak in ResourceManager with SIMPLE mode
  

• YARN-3802. Major bug reported by zhihai xu and fixed by zhihai xu (resourcemanager)
  Two RMNodes for the same NodeId are used in RM sometimes after NM is reconnected.
  

• YARN-3798. Blocker bug reported by Bibin A Chundatt and fixed by Varun Saxena (resourcemanager)
  ZKRMStateStore shouldn't create new session without occurrance of SESSIONEXPIED
  

• YARN-3793. Major bug reported by Karthik Kambatla and fixed by Varun Saxena (nodemanager)
  Several NPEs when deleting local files on NM recovery
  

• YARN-3780. Minor bug reported by zhihai xu and fixed by zhihai xu (resourcemanager)
  Should use equals when compare Resource in RMNodeImpl#ReconnectNodeTransition
  

• YARN-3740. Major sub-task reported by Xuan Gong and fixed by Xuan Gong (resourcemanager , webapp , yarn)
  Fixed the typo with the configuration name: APPLICATION_HISTORY_PREFIX_MAX_APPS
  

• YARN-3727. Major improvement reported by zhihai xu and fixed by zhihai xu (nodemanager)
  For better error recovery, check if the directory exists before using it for localization.
  

• YARN-3700. Major sub-task reported by Xuan Gong and fixed by Xuan Gong (resourcemanager , webapp , yarn)
  ATS Web Performance issue at load time when large number of jobs
  

• YARN-3697. Critical bug reported by zhihai xu and fixed by zhihai xu (fairscheduler)
  FairScheduler: ContinuousSchedulingThread can fail to shutdown
  

• YARN-3690. Major bug reported by Akira AJISAKA and fixed by Brahma Reddy Battula (api , site)
  [JDK8] 'mvn site' fails
  

• YARN-3624. Major bug reported by Mit Desai and fixed by Mit Desai (timelineserver)
  ApplicationHistoryServer reverses the order of the filters it gets
  

• YARN-3619. Major bug reported by Jason Lowe and fixed by zhihai xu (nodemanager)
  ContainerMetrics unregisters during getMetrics and leads to ConcurrentModificationException
  

• YARN-3580. Major test reported by Robert Kanter and fixed by Robert Kanter (test)
  [JDK 8] TestClientRMService.testGetLabelsToNodes fails
  

• YARN-3535. Critical bug reported by Peng Zhang and fixed by Peng Zhang (capacityscheduler , fairscheduler , resourcemanager)
  Scheduler must re-request container resources when RMContainer transitions from ALLOCATED to KILLED
  

• YARN-3508. Major bug reported by Jason Lowe and fixed by Varun Saxena (resourcemanager , scheduler)
  Prevent processing preemption events on the main RM dispatcher
  

• YARN-3248. Major improvement reported by Varun Vasudev and fixed by Varun Vasudev (capacityscheduler , resourcemanager)
  Display count of nodes blacklisted by apps in the web UI
  

• YARN-3170. Major improvement reported by Allen Wittenauer and fixed by Brahma Reddy Battula (documentation)
  YARN architecture document needs updating
  

• YARN-3136. Major sub-task reported by Jason Lowe and fixed by Sunil G (scheduler)
  getTransferredContainers can be a bottleneck during AM registration
  

• YARN-2902. Major sub-task reported by Jason Lowe and fixed by Varun Saxena (nodemanager)
  Killing a container that is localizing can orphan resources in the DOWNLOADING state
  

• YARN-2890. Major bug reported by Mit Desai and fixed by Mit Desai
  MiniYarnCluster should turn on timeline service if configured to do so
  

• YARN-2859. Critical bug reported by Hitesh Shah and fixed by Vinod Kumar Vavilapalli (timelineserver)
  ApplicationHistoryServer binds to default port 8188 in MiniYARNCluster
  

• YARN-2801. Major sub-task reported by Gururaj Shetty and fixed by Wangda Tan (documentation)
  Add documentation for node labels feature
  

• YARN-2513. Major sub-task reported by Jonathan Eagles and fixed by Jonathan Eagles (timelineserver)
  Host framework UIs in YARN for use with the ATS
  

• YARN-2019. Critical bug reported by Junping Du and fixed by Jian He
  Retrospect on decision of making RM crashed if any exception throw in ZKRMStateStore
  

• MAPREDUCE-6549. Major bug reported by Dustin Cote and fixed by Wilfred Spiegelenburg (mrv1 , mrv2)
  multibyte delimiters with LineRecordReader cause duplicate records
  

• MAPREDUCE-6540. Major bug reported by Sangjin Lee and fixed by Sangjin Lee (test)
  TestMRTimelineEventHandling fails
  

• MAPREDUCE-6528. Critical bug reported by Junping Du and fixed by Junping Du (jobhistoryserver)
  Memory leak for HistoryFileManager.getJobSummary()
  

• MAPREDUCE-6518. Major bug reported by Nathan Roberts and fixed by Chang Li (mrv2 , nodemanager)
  Set SO_KEEPALIVE on shuffle connections
  

• MAPREDUCE-6497. Major bug reported by Shinichi Yamashita and fixed by Shinichi Yamashita
  Fix wrong value of JOB_FINISHED event in JobHistoryEventHandler
  

• MAPREDUCE-6492. Critical bug reported by Bibin A Chundatt and fixed by Bibin A Chundatt
  AsyncDispatcher exit with NPE on TaskAttemptImpl#sendJHStartEventForAssignedFailTask
  

• MAPREDUCE-6481. Critical bug reported by zhihai xu and fixed by zhihai xu (mrv2)
  LineRecordReader may give incomplete record and wrong position/key information for uncompressed input sometimes.
  

• MAPREDUCE-6474. Major bug reported by Nathan Roberts and fixed by Kuhu Shukla (mrv2 , nodemanager)
  ShuffleHandler can possibly exhaust nodemanager file descriptors
  

• MAPREDUCE-6472. Major bug reported by Jason Lowe and fixed by Naganarasimha G R (mr-am)
  MapReduce AM should have java.io.tmpdir=./tmp to be consistent with tasks
  

• MAPREDUCE-6454. Critical bug reported by Junping Du and fixed by Junping Du
  MapReduce doesn't set the HADOOP_CLASSPATH for jar lib in distributed cache.
  

• MAPREDUCE-6451. Major bug reported by Kuhu Shukla and fixed by Kuhu Shukla (distcp)
  DistCp has incorrect chunkFilePath for multiple jobs when strategy is dynamic
  

• MAPREDUCE-6442. Major bug reported by Chang Li and fixed by Chang Li (client)
  Stack trace is missing when error occurs in client protocol provider's constructor
  

• MAPREDUCE-6439. Critical bug reported by Anubhav Dhoot and fixed by Anubhav Dhoot
  AM may fail instead of retrying if RM shuts down during the allocate call
  

• MAPREDUCE-6426. Major bug reported by Devaraj K and fixed by zhihai xu (test)
  TestShuffleHandler#testGetMapOutputInfo is failing
  

• MAPREDUCE-6425. Major bug reported by zhihai xu and fixed by zhihai xu (mrv2 , nodemanager)
  ShuffleHandler passes wrong "base" parameter to getMapOutputInfo if mapId is not in the cache.
  

• MAPREDUCE-6377. Minor bug reported by Bibin A Chundatt and fixed by zhihai xu (jobhistoryserver)
  JHS sorting on state column not working in webUi
  

• MAPREDUCE-6273. Minor bug reported by zhihai xu and fixed by zhihai xu (jobhistoryserver)
  HistoryFileManager should check whether summaryFile exists to avoid FileNotFoundException causing HistoryFileInfo into MOVE_FAILED state
  

• MAPREDUCE-5982. Major bug reported by Jason Lowe and fixed by Chang Li (mr-am)
  Task attempts that fail from the ASSIGNED state can disappear
  

• MAPREDUCE-5948. Critical bug reported by Kris Geusebroek and fixed by Akira AJISAKA
  org.apache.hadoop.mapred.LineRecordReader does not handle multibyte record delimiters well
  

• MAPREDUCE-5883. Minor bug reported by Nathan Roberts and fixed by Nathan Roberts
  "Total megabyte-seconds" in job counters is slightly misleading
  

• MAPREDUCE-5649. Major bug reported by stanley shi and fixed by Gera Shegalov (mrv2)
  Reduce cannot use more than 2G memory for the final merge
  

• HDFS-9574. Major bug reported by Kihwal Lee and fixed by Kihwal Lee
  Reduce client failures during datanode restart
  

• HDFS-9470. Critical bug reported by Xiao Chen and fixed by Xiao Chen
  Encryption zone on root not loaded from fsimage after NN restart
  

• HDFS-9445. Blocker bug reported by Kihwal Lee and fixed by Walter Su
  Datanode may deadlock while handling a bad volume
  

• HDFS-9434. Major improvement reported by Tsz Wo Nicholas Sze and fixed by Tsz Wo Nicholas Sze (namenode)
  Recommission a datanode with 500k blocks may pause NN for 30 seconds
  

• HDFS-9431. Major bug reported by Kazuho Fujii and fixed by Kazuho Fujii (hdfs-client)
  DistributedFileSystem#concat fails if the target path is relative.
  

• HDFS-9426. Blocker bug reported by Kihwal Lee and fixed by Kihwal Lee
  Rollingupgrade finalization is not backward compatible
  

• HDFS-9413. Critical bug reported by Brahma Reddy Battula and fixed by Brahma Reddy Battula
  getContentSummary() on standby should throw StandbyException
  

• HDFS-9317. Major bug reported by Akira AJISAKA and fixed by Akira AJISAKA (documentation)
  Document fsck -blockId and -storagepolicy options in branch-2.7
  

• HDFS-9305. Major bug reported by Chris Nauroth and fixed by Arpit Agarwal (datanode)
  Delayed heartbeat processing causes storm of subsequent heartbeats
  

• HDFS-9294. Blocker bug reported by DENG FEI and fixed by Brahma Reddy Battula (hdfs-client)
  DFSClient deadlock when close file and failed to renew lease
  

• HDFS-9290. Blocker bug reported by Tony Wu and fixed by Tony Wu
  DFSClient#callAppend() is not backward compatible for slightly older NameNodes
  

• HDFS-9289. Critical bug reported by Chang Li and fixed by Chang Li
  Make DataStreamer#block thread safe and verify genStamp in commitBlock
  

• HDFS-9273. Critical bug reported by Xiao Chen and fixed by Xiao Chen (namenode)
  ACLs on root directory may be lost after NN restart
  

• HDFS-9221. Major improvement reported by Staffan Friberg and fixed by Staffan Friberg (performance)
  HdfsServerConstants#ReplicaState#getState should avoid calling values() since it creates a temporary array
  

• HDFS-9220. Blocker bug reported by Bogdan Raducanu and fixed by Jing Zhao
  Reading small file (< 512 bytes) that is open for append fails due to incorrect checksum
  

• HDFS-9178. Critical bug reported by Kihwal Lee and fixed by Kihwal Lee
  Slow datanode I/O can cause a wrong node to be marked bad
  

• HDFS-9106. Critical bug reported by Kihwal Lee and fixed by Kihwal Lee
  Transfer failure during pipeline recovery causes permanent write failures
  

• HDFS-9083. Blocker bug reported by Rushabh S Shah and fixed by Rushabh S Shah (namenode)
  Replication violates block placement policy.
  

• HDFS-9043. Minor bug reported by J.Andreina and fixed by J.Andreina (documentation)
  Doc updation for commands in HDFS Federation
  

• HDFS-9042. Minor bug reported by J.Andreina and fixed by J.Andreina (documentation)
  Update document for the Storage policy name
  

• HDFS-9033. Major bug reported by Archana T and fixed by Brahma Reddy Battula
  dfsadmin -metasave prints "NaN" for cache used%
  

• HDFS-8995. Critical bug reported by Kihwal Lee and fixed by Kihwal Lee
  Flaw in registration bookeeping can make DN die on reconnect
  

• HDFS-8950. Major bug reported by Daniel Templeton and fixed by Daniel Templeton (datanode , namenode)
  NameNode refresh doesn't remove DataNodes that are no longer in the allowed list
  

• HDFS-8891. Blocker bug reported by Yong Zhang and fixed by Yong Zhang
  HDFS concat should keep srcs order
  

• HDFS-8879. Major bug reported by Kihwal Lee and fixed by Xiaoyu Yao (namenode)
  Quota by storage type usage incorrectly initialized upon namenode restart
  

• HDFS-8867. Major bug reported by Rushabh S Shah and fixed by Daryn Sharp
  Enable optimized block reports
  

• HDFS-8863. Critical bug reported by Kihwal Lee and fixed by Kihwal Lee
  The remaining space check in BlockPlacementPolicyDefault is flawed
  

• HDFS-8852. Major bug reported by Hong Dai Thanh and fixed by Ajith S (documentation)
  HDFS architecture documentation of version 2.x is outdated about append write support
  

• HDFS-8850. Major bug reported by Colin Patrick McCabe and fixed by Colin Patrick McCabe (datanode)
  VolumeScanner thread exits with exception if there is no block pool to be scanned but there are suspicious blocks
  

• HDFS-8846. Major bug reported by Zhe Zhang and fixed by Zhe Zhang (namenode)
  Add a unit test for INotify functionality across a layout version upgrade
  

• HDFS-8806. Major bug reported by Zhe Zhang and fixed by Zhe Zhang
  Inconsistent metrics: number of missing blocks with replication factor 1 not properly cleared
  

• HDFS-8767. Critical bug reported by Haohui Mai and fixed by Kanaka Kumar Avvaru
  RawLocalFileSystem.listStatus() returns null for UNIX pipefile
  

• HDFS-8722. Critical improvement reported by Kihwal Lee and fixed by Kihwal Lee
  Optimize datanode writes for small writes and flushes
  

• HDFS-8676. Critical bug reported by Kihwal Lee and fixed by Walter Su
  Delayed rolling upgrade finalization can cause heartbeat expiration and write failures
  

• HDFS-8659. Major improvement reported by Yongjun Zhang and fixed by Yongjun Zhang (datanode)
  Block scanner INFO message is spamming logs
  

• HDFS-8656. Critical bug reported by Andrew Wang and fixed by Andrew Wang (rolling upgrades)
  Preserve compatibility of ClientProtocol#rollingUpgrade after finalization
  

• HDFS-8615. Major bug reported by Akira AJISAKA and fixed by Brahma Reddy Battula (documentation)
  Correct HTTP method in WebHDFS document
  

• HDFS-8431. Critical bug reported by Sumana Sathish and fixed by Anu Engineer (scripts)
  hdfs crypto class not found in Windows
  

• HDFS-8384. Minor improvement reported by Tsz Wo Nicholas Sze and fixed by Jing Zhao (namenode)
  Allow NN to startup if there are files having a lease but are not under construction
  

• HDFS-8219. Major bug reported by Peter Shi and fixed by Surendra Singh Lilhore
  setStoragePolicy with folder behavior is different after cluster restart
  

• HDFS-8099. Minor bug reported by Charles Lamb and fixed by Charles Lamb (hdfs-client)
  Change "DFSInputStream has been closed already" message to debug log level
  

• HDFS-8046. Major bug reported by Kihwal Lee and fixed by Kihwal Lee
  Allow better control of getContentSummary
  

• HDFS-7725. Major bug reported by Ming Ma and fixed by Ming Ma
  Incorrect "nodes in service" metrics caused all writes to fail
  

• HDFS-7645. Major improvement reported by Nathan Roberts and fixed by Keisuke Ogiwara (datanode)
  Rolling upgrade is restoring blocks from trash multiple times
  

• HDFS-7609. Critical bug reported by Carrey Zhan and fixed by Ming Ma (namenode)
  Avoid retry cache collision when Standby NameNode loading edits
  

• HDFS-7314. Major improvement reported by Ming Ma and fixed by Ming Ma
  When the DFSClient lease cannot be renewed, abort open-for-write files rather than the entire DFSClient
  

• HDFS-6945. Critical bug reported by Akira AJISAKA and fixed by Akira AJISAKA (namenode)
  BlockManager should remove a block from excessReplicateMap and decrement ExcessBlocks metric when the block is removed
  

• HADOOP-12577. Blocker bug reported by Wei-Chiu Chuang and fixed by Wei-Chiu Chuang (build , security)
  Bump up commons-collections version to 3.2.2 to address a security flaw
  

• HADOOP-12526. Major bug reported by Sangjin Lee and fixed by Sangjin Lee (build)
  [Branch-2] there are duplicate dependency definitions in pom's
  

• HADOOP-12465. Minor bug reported by Martin Petricek and fixed by Jagadesh Kiran N (documentation)
  Incorrect javadoc in WritableUtils.java
  

• HADOOP-12464. Major bug reported by Kihwal Lee and fixed by Kihwal Lee (ipc)
  Interrupted client may try to fail-over and retry
  

• HADOOP-12451. Blocker bug reported by Karthik Kambatla and fixed by Karthik Kambatla (scripts)
  [Branch-2] Setting HADOOP_HOME explicitly should be allowed
  

• HADOOP-12415. Major bug reported by Konstantin Boudnik and fixed by Tom Zeng (nfs)
  hdfs and nfs builds broken on -missing compile-time dependency on netty
  

• HADOOP-12413. Major improvement reported by zhihai xu and fixed by zhihai xu (security)
  AccessControlList should avoid calling getGroupNames in isUserInList with empty groups.
  

• HADOOP-12359. Major bug reported by Daniel Templeton and fixed by Jagadesh Kiran N (documentation)
  hadoop fs -getmerge doc is wrong
  

• HADOOP-12304. Blocker bug reported by Chris Nauroth and fixed by Chris Nauroth (fs)
  Applications using FileContext fail with the default file system configured to be wasb/s3/etc.
  

• HADOOP-12280. Minor improvement reported by Masatake Iwasaki and fixed by Masatake Iwasaki (test)
  Skip unit tests based on maven profile rather than NativeCodeLoader.isNativeCodeLoaded
  

• HADOOP-12232. Major improvement reported by Chris Nauroth and fixed by Chris Nauroth (build)
  Upgrade Tomcat dependency to 6.0.44.
  

• HADOOP-12230. Minor bug reported by Steve Loughran and fixed by Rakesh R (build)
  hadoop-project declares duplicate, conflicting curator dependencies
  

• HADOOP-12213. Minor bug reported by Oleg Zhurakousky and fixed by Kuhu Shukla
  Interrupted exception can occur when Client#stop is called
  

• HADOOP-12191. Major bug reported by Jason Lowe and fixed by Brahma Reddy Battula (io)
  Bzip2Factory is not thread safe
  

• HADOOP-12186. Major bug reported by zhihai xu and fixed by zhihai xu (ha)
  ActiveStandbyElector shouldn't call monitorLockNodeAsync multiple times
  

• HADOOP-12006. Major bug reported by Akira AJISAKA and fixed by Akira AJISAKA
  Remove unimplemented option for `hadoop fs -ls` from document in branch-2.7
  

• HADOOP-11932. Critical bug reported by Jian He and fixed by Brahma Reddy Battula
  MetricsSinkAdapter hangs when being stopped
  

• HADOOP-11812. Blocker improvement reported by Gera Shegalov and fixed by Gera Shegalov (fs)
  Implement listLocatedStatus for ViewFileSystem to speed up split calculation
  

• HADOOP-11491. Critical bug reported by Gera Shegalov and fixed by Brahma Reddy Battula (fs)
  HarFs incorrectly declared as requiring an authority
  

• HADOOP-10365. Minor bug reported by Ted Yu and fixed by Kiran Kumar M R (util)
  BufferedOutputStream in FileUtil#unpackEntries() should be closed in finally block
  

• HADOOP-9242. Major bug reported by Andrey Klochkov and fixed by Andrey Klochkov (test)
  Duplicate surefire plugin config in hadoop-common
  

• HADOOP-8151. Major bug reported by Todd Lipcon and fixed by Matt Foley (io , native)
  Error handling in snappy decompressor throws invalid exceptions
  

• HADOOP-7139. Major improvement reported by Stephen Rose and fixed by Kanaka Kumar Avvaru (io)
  Allow appending to existing SequenceFiles
  

  Existing sequence files can be appended.

• HADOOP-5323. Minor improvement reported by Suman Sehgal and fixed by Weiwei Yang (documentation)
  Trash documentation should describe its directory structure and configurations