| HDFS-13642 | Creating a file with block size smaller than EC policy’s cell size should fail | Major | erasure-coding | Xiao Chen | Xiao Chen | 
| HADOOP-15948 | Inconsistency in get and put syntax if filename/dirname contains space | Minor | fs | vivek kumar | Ayush Saxena | 
| HDFS-13816 | dfs.getQuotaUsage() throws NPE on non-existent dir instead of FileNotFoundException | Major | namenode | Vinayakumar B | Vinayakumar B | 
| HADOOP-15966 | Hadoop Kerberos broken on macos as java.security.krb5.realm is reset: Null realm name (601) | Major | scripts | Steve Loughran | Steve Loughran | 
| HADOOP-16028 | Fix NetworkTopology chooseRandom function to support excluded nodes | Major | . | Sihai Ke | Sihai Ke | 
| YARN-9162 | Fix TestRMAdminCLI#testHelp | Major | resourcemanager, test | Ayush Saxena | Ayush Saxena | 
| HADOOP-16031 | TestSecureLogins#testValidKerberosName fails | Major | security | Akira Ajisaka | Akira Ajisaka | 
| HADOOP-16016 | TestSSLFactory#testServerWeakCiphers sporadically fails in precommit builds | Major | security, test | Jason Lowe | Akira Ajisaka | 
| HDFS-14198 | Upload and Create button doesn’t get enabled after getting reset. | Major | . | Ayush Saxena | Ayush Saxena | 
| YARN-9203 | Fix typos in yarn-default.xml | Trivial | documentation | Rahul Padmanabhan | Rahul Padmanabhan | 
| HDFS-14207 | ZKFC should catch exception when ha configuration missing | Major | hdfs | Fei Hui | Fei Hui | 
| HDFS-14218 | EC: Ls -e throw NPE when directory ec policy is disabled | Major | . | Surendra Singh Lilhore | Ayush Saxena | 
| YARN-9210 | RM nodes web page can not display node info | Blocker | yarn | Jiandan Yang | Jiandan Yang | 
| YARN-8961 | [UI2] Flow Run End Time shows ‘Invalid date’ | Major | . | Charan Hebri | Akhil PB | 
| YARN-7088 | Add application launch time to Resource Manager REST API | Major | . | Abdullah Yousufi | Kanwaljeet Sachdev | 
| YARN-9222 | Print launchTime in ApplicationSummary | Major | . | Jonathan Hung | Jonathan Hung | 
| YARN-8901 | Restart “NEVER” policy does not work with component dependency | Critical | . | Yesha Vora | Suma Shivaprasad | 
| YARN-9237 | NM should ignore sending finished apps to RM during RM fail-over | Major | yarn | Jiandan Yang | Jiandan Yang | 
| YARN-6616 | YARN AHS shows submitTime for jobs same as startTime | Minor | . | Prabhu Joseph | Prabhu Joseph | 
| YARN-9099 | GpuResourceAllocator#getReleasingGpus calculates number of GPUs in a wrong way | Major | . | Szilard Nemeth | Szilard Nemeth | 
| HADOOP-16086 | Backport HADOOP-15549 to branch-3.1 | Major | metrics | Yuming Wang | Todd Lipcon | 
| YARN-9206 | RMServerUtils does not count SHUTDOWN as an accepted state | Major | . | Kuhu Shukla | Kuhu Shukla | 
| HADOOP-16096 | HADOOP-15281/distcp -Xdirect needs to use commons-logging on 3.1 | Critical | . | Eric Payne | Steve Loughran | 
| HDFS-14140 | JournalNodeSyncer authentication is failing in secure cluster | Major | journal-node, security | Surendra Singh Lilhore | Surendra Singh Lilhore | 
| YARN-9257 | Distributed Shell client throws a NPE for a non-existent queue | Major | distributed-shell | Charan Hebri | Charan Hebri | 
| YARN-8761 | Service AM support for decommissioning component instances | Major | . | Billie Rinaldi | Billie Rinaldi | 
| HDFS-14266 | EC : Fsck -blockId shows null for EC Blocks if One Block Is Not Available. | Major | . | Harshakiran Reddy | Ayush Saxena | 
| HDFS-14274 | EC: NPE While Listing EC Policy For A Directory Following Replication Policy. | Major | erasure-coding | Souryakanta Dwivedy | Ayush Saxena | 
| HDFS-14263 | Remove unnecessary block file exists check from FsDatasetImpl#getBlockInputStream() | Major | datanode | Surendra Singh Lilhore | Surendra Singh Lilhore | 
| YARN-7761 | [UI2] Clicking ‘master container log’ or ‘Link’ next to ‘log’ under application’s appAttempt goes to Old UI’s Log link | Major | yarn-ui-v2 | Sumana Sathish | Akhil PB | 
| YARN-9295 | [UI2] Fix label typo in Cluster Overview page | Trivial | yarn-ui-v2 | Charan Hebri | Charan Hebri | 
| YARN-9284 | Fix the unit of yarn.service.am-resource.memory in the document | Minor | documentation, yarn-native-services | Masahiro Tanaka | Masahiro Tanaka | 
| YARN-9283 | Javadoc of LinuxContainerExecutor#addSchedPriorityCommand has a wrong property name as reference | Minor | documentation | Szilard Nemeth | Adam Antal | 
| YARN-9286 | [Timeline Server] Sorting based on FinalStatus shows pop-up message | Minor | timelineserver | Nallasivan | Bilwa S T | 
| HDFS-14081 | hdfs dfsadmin -metasave metasave_test results NPE | Major | hdfs | Shweta | Shweta | 
| HADOOP-15813 | Enable more reliable SSL connection reuse | Major | common | Daryn Sharp | Daryn Sharp | 
| HADOOP-16105 | WASB in secure mode does not set connectingUsingSAS | Major | fs/azure | Steve Loughran | Steve Loughran | 
| YARN-9238 | Avoid allocating opportunistic containers to previous/removed/non-exist application attempt | Critical | . | lujie | lujie | 
| YARN-9118 | Handle exceptions with parsing user defined GPU devices in GpuDiscoverer | Major | . | Szilard Nemeth | Szilard Nemeth | 
| YARN-9317 | Avoid repeated YarnConfiguration#timelineServiceV2Enabled check | Major | . | Bibin A Chundatt | Prabhu Joseph | 
| YARN-9213 | RM Web UI v1 does not show custom resource allocations for containers page | Major | . | Szilard Nemeth | Szilard Nemeth | 
| YARN-9248 | RMContainerImpl:Invalid event: ACQUIRED at KILLED | Major | . | lujie | lujie | 
| HADOOP-16018 | DistCp won’t reassemble chunks when blocks per chunk > 0 | Major | tools/distcp | Kai Xie | Kai Xie | 
| YARN-9334 | YARN Service Client does not work with SPNEGO when knox is configured | Major | yarn-native-services | Tarun Parimi | Billie Rinaldi | 
| HDFS-14305 | Serial number in BlockTokenSecretManager could overlap between different namenodes | Major | namenode, security | Chao Sun | He Xiaoqiao | 
| HDFS-14314 | fullBlockReportLeaseId should be reset after registering to NN | Critical | datanode | star | star | 
| YARN-8803 | [UI2] Show flow runs in the order of recently created time in graph widgets | Major | yarn-ui-v2 | Akhil PB | Akhil PB | 
| HADOOP-16114 | NetUtils#canonicalizeHost gives different value for same host | Minor | net | Praveen Krishna | Praveen Krishna | 
| HDFS-14317 | Standby does not trigger edit log rolling when in-progress edit log tailing is enabled | Critical | . | Ekanth Sethuramalingam | Ekanth Sethuramalingam | 
| HDFS-14333 | Datanode fails to start if any disk has errors during Namenode registration | Major | datanode | Stephen O’Donnell | Stephen O’Donnell | 
| HADOOP-16192 | CallQueue backoff bug fixes: doesn’t perform backoff when add() is used, and doesn’t update backoff when refreshed | Major | ipc | Erik Krogen | Erik Krogen | 
| HDFS-14037 | Fix SSLFactory truststore reloader thread leak in URLConnectionFactory | Major | hdfs-client, webhdfs | Takanobu Asanuma | Takanobu Asanuma | 
| HADOOP-16225 | Fix links to the developer mailing lists in DownstreamDev.md | Minor | documentation | Akira Ajisaka | Wanqiang Ji | 
| HADOOP-16232 | Fix errors in the checkstyle configration xmls | Major | build | Akira Ajisaka | Wanqiang Ji | 
| HDFS-14389 | getAclStatus returns incorrect permissions and owner when an iNodeAttributeProvider is configured | Major | namenode | Stephen O’Donnell | Stephen O’Donnell | 
| HDFS-14407 | Fix misuse of SLF4j logging API in DatasetVolumeChecker#checkAllVolumes | Minor | . | Wanqiang Ji | Wanqiang Ji | 
| YARN-9413 | Queue resource leak after app fail for CapacityScheduler | Major | capacityscheduler | Tao Yang | Tao Yang | 
| HADOOP-14544 | DistCp documentation for command line options is misaligned. | Minor | documentation | Chris Nauroth | Masatake Iwasaki | 
| HDFS-10477 | Stop decommission a rack of DataNodes caused NameNode fail over to standby | Major | namenode | yunjiong zhao | yunjiong zhao | 
| YARN-6695 | Race condition in RM for publishing container events vs appFinished events causes NPE | Critical | . | Rohith Sharma K S | Prabhu Joseph | 
| YARN-8622 | NodeManager native build fails due to getgrouplist not found on macOS | Major | nodemanager | Ewan Higgs | Siyao Meng | 
| HADOOP-16265 | Configuration#getTimeDuration is not consistent between default value and manual settings. | Major | . | star | star | 
| YARN-9307 | node_partitions constraint does not work | Major | . | kyungwan nam | kyungwan nam | 
| HDFS-13677 | Dynamic refresh Disk configuration results in overwriting VolumeMap | Blocker | . | xuzq | xuzq | 
| YARN-9285 | RM UI progress column is of wrong type | Minor | yarn | Ahmed Hussein | Ahmed Hussein | 
| HADOOP-16278 | With S3A Filesystem, Long Running services End up Doing lot of GC and eventually die | Major | common, hadoop-aws, metrics | Rajat Khandelwal | Rajat Khandelwal | 
| YARN-9504 | [UI2] Fair scheduler queue view page does not show actual capacity | Major | fairscheduler, yarn-ui-v2 | Zoltan Siegl | Zoltan Siegl | 
| YARN-9519 | TFile log aggregation file format is not working for yarn.log-aggregation.TFile.remote-app-log-dir config | Major | log-aggregation | Adam Antal | Adam Antal | 
| HADOOP-16247 | NPE in FsUrlConnection | Major | hdfs-client | Karthik Palanisamy | Karthik Palanisamy | 
| HADOOP-16248 | MutableQuantiles leak memory under heavy load | Major | metrics | Alexis Daboville | Alexis Daboville | 
| HDFS-14323 | Distcp fails in Hadoop 3.x when 2.x source webhdfs url has special characters in hdfs file path | Major | webhdfs | Srinivasu Majeti | Srinivasu Majeti | 
| MAPREDUCE-7205 | Treat container scheduler kill exit code as a task attempt killing event | Major | applicationmaster, mr-am, mrv2 | Wanqiang Ji | Wanqiang Ji | 
| HDFS-14500 | NameNode StartupProgress continues to report edit log segments after the LOADING_EDITS phase is finished | Major | namenode | Erik Krogen | Erik Krogen | 
| HADOOP-16331 | Fix ASF License check in pom.xml | Major | . | Wanqiang Ji | Akira Ajisaka | 
| YARN-9542 | Fix LogsCLI guessAppOwner ignores custom file format suffix | Minor | log-aggregation | Prabhu Joseph | Prabhu Joseph | 
| HDFS-14512 | ONE_SSD policy will be violated while write data with DistributedFileSystem.create(….favoredNodes) | Major | . | Shen Yinjie | Ayush Saxena | 
| HADOOP-16334 | Fix yetus-wrapper not working when HADOOP_YETUS_VERSION >= 0.9.0 | Major | yetus | Wanqiang Ji | Wanqiang Ji | 
| HDFS-14521 | Suppress setReplication logging. | Major | . | Kihwal Lee | Kihwal Lee | 
| YARN-9507 | Fix NPE in NodeManager#serviceStop on startup failure | Minor | . | Bilwa S T | Bilwa S T | 
| YARN-8947 | [UI2] Active User info missing from UI2 | Major | yarn-ui-v2 | Akhil PB | Akhil PB | 
| YARN-8906 | [UI2] NM hostnames not displayed correctly in Node Heatmap Chart | Major | . | Charan Hebri | Akhil PB | 
| YARN-8625 | Aggregate Resource Allocation for each job is not present in ATS | Major | ATSv2 | Prabhu Joseph | Prabhu Joseph | 
| HADOOP-16345 | Potential NPE when instantiating FairCallQueue metrics | Major | ipc | Erik Krogen | Erik Krogen | 
| YARN-9594 | Fix missing break statement in ContainerScheduler#handle | Major | . | lujie | lujie | 
| YARN-9565 | RMAppImpl#ranNodes not cleared on FinalTransition | Major | . | Bibin A Chundatt | Bilwa S T | 
| YARN-9547 | ContainerStatusPBImpl default execution type is not returned | Major | . | Bibin A Chundatt | Bilwa S T | 
| HDFS-13231 | Extend visualization for Decommissioning, Maintenance Mode under Datanode tab in the NameNode UI | Major | datanode, namenode | Haibo Yan | Stephen O’Donnell | 
| YARN-9621 | FIX TestDSWithMultipleNodeManager.testDistributedShellWithPlacementConstraint on branch-3.1 | Major | distributed-shell, test | Peter Bacsko | Prabhu Joseph | 
| HDFS-14535 | The default 8KB buffer in requestFileDescriptors#BufferedOutputStream is causing lots of heap allocation in HBase when using short-circut read | Major | hdfs-client | Zheng Hu | Zheng Hu | 
| HDFS-13730 | BlockReaderRemote.sendReadResult throws NPE | Major | hdfs-client | Wei-Chiu Chuang | Yuanbo Liu | 
| YARN-9584 | Should put initializeProcessTrees method call before get pid | Critical | nodemanager | Wanqiang Ji | Wanqiang Ji | 
| HDFS-14010 | Pass correct DF usage to ReservedSpaceCalculator builder | Minor | . | Lukas Majercak | Lukas Majercak | 
| HDFS-14078 | Admin helper fails to prettify NullPointerExceptions | Major | . | Elek, Marton | Elek, Marton | 
| HDFS-14101 | Random failure of testListCorruptFilesCorruptedBlock | Major | test | Kihwal Lee | Zsolt Venczel | 
| HDFS-14465 | When the Block expected replications is larger than the number of DataNodes, entering maintenance will never exit. | Major | . | Yicong Cai | Yicong Cai | 
| HDFS-12487 | FsDatasetSpi.isValidBlock() lacks null pointer check inside and neither do the callers | Major | balancer & mover, diskbalancer | liumi | liumi | 
| HDFS-14074 | DataNode runs async disk checks  maybe  throws NullPointerException, and DataNode failed to register to NameSpace. | Major | hdfs | guangyi lu | guangyi lu | 
| HDFS-14541 | When evictableMmapped or evictable size is zero, do not throw NoSuchElementException | Major | hdfs-client, performance | Zheng Hu | Lisheng Sun | 
| HDFS-14598 | Findbugs warning caused by HDFS-12487 | Minor | diskbalancer | Wei-Chiu Chuang | He Xiaoqiao | 
| YARN-9639 | DecommissioningNodesWatcher cause memory leak | Blocker | . | Bibin A Chundatt | Bilwa S T | 
| YARN-9327 | Improve synchronisation in ProtoUtils#convertToProtoFormat block | Critical | . | Bibin A Chundatt | Bibin A Chundatt | 
| YARN-9655 | AllocateResponse in FederationInterceptor lost  applicationPriority | Major | federation | hunshenshi | hunshenshi | 
| HADOOP-16385 | Namenode crashes with “RedundancyMonitor thread received Runtime exception” | Major | . | krishna reddy | Ayush Saxena | 
| YARN-9644 | First RMContext object is always leaked during switch over | Blocker | . | Bibin A Chundatt | Bibin A Chundatt | 
| HDFS-14629 | Property value Hard Coded in DNConf.java | Trivial | . | hemanthboyina | hemanthboyina | 
| YARN-9557 | Application fails in diskchecker when ReadWriteDiskValidator is configured. | Critical | nodemanager | Anuruddh Nayak | Bilwa S T | 
| HDFS-12703 | Exceptions are fatal to decommissioning monitor | Critical | namenode | Daryn Sharp | He Xiaoqiao | 
| HDFS-12748 | NameNode memory leak when accessing webhdfs GETHOMEDIRECTORY | Major | hdfs | Jiandan Yang | Weiwei Yang | 
| YARN-9625 | UI2 - No link to a queue on the Queues page for Fair Scheduler | Major | . | Charan Hebri | Zoltan Siegl | 
| HDFS-14466 | Add a regression test for HDFS-14323 | Minor | fs, test, webhdfs | Yuya Ebihara | Masatake Iwasaki | 
| YARN-9235 | If linux container executor is not set for a GPU cluster GpuResourceHandlerImpl is not initialized and NPE is thrown | Major | yarn | Antal Bálint Steinbach | Adam Antal | 
| YARN-9626 | UI2 - Fair scheduler queue apps page issues | Major | . | Charan Hebri | Zoltan Siegl | 
| YARN-9682 | Wrong log message when finalizing the upgrade | Trivial | . | kyungwan nam | kyungwan nam | 
| HADOOP-16440 | Distcp can not preserve timestamp with -delete  option | Major | . | ludun | ludun | 
| MAPREDUCE-7076 | TestNNBench#testNNBenchCreateReadAndDelete failing in our internal build | Minor | test | Rushabh S Shah | kevin su | 
| YARN-9668 | UGI conf doesn’t read user overridden configurations on RM and NM startup | Major | . | Jonathan Hung | Jonathan Hung | 
| HADOOP-9844 | NPE when trying to create an error message response of SASL RPC | Major | ipc | Steve Loughran | Steve Loughran | 
| HADOOP-16245 | Enabling SSL within LdapGroupsMapping can break system SSL configs | Major | common, security | Erik Krogen | Erik Krogen | 
| HDFS-14429 | Block remain in COMMITTED but not COMPLETE caused by Decommission | Major | . | Yicong Cai | Yicong Cai | 
| HADOOP-16435 | RpcMetrics should not be retained forever | Critical | rpc-server | Zoltan Haindrich | Zoltan Haindrich | 
| YARN-9596 | QueueMetrics has incorrect metrics when labelled partitions are involved | Major | capacity scheduler | Muhammad Samir Khan | Muhammad Samir Khan | 
| MAPREDUCE-7225 | Fix broken current folder expansion during MR job start | Major | mrv2 | Adam Antal | Peter Bacsko | 
| HDFS-13529 | Fix default trash policy emptier trigger time correctly | Major | namenode | He Xiaoqiao | He Xiaoqiao | 
| HADOOP-15681 | AuthenticationFilter should generate valid date format for Set-Cookie header regardless of default Locale | Minor | security | Cao Manh Dat | Cao Manh Dat | 
| HDFS-14685 | DefaultAuditLogger doesn’t print CallerContext | Major | hdfs | xuzq | xuzq | 
| HDFS-14462 | WebHDFS throws “Error writing request body to server” instead of DSQuotaExceededException | Major | webhdfs | Erik Krogen | Simbarashe Dzinamarira | 
| HDFS-14557 | JournalNode error: Can’t scan a pre-transactional edit log | Major | ha | Wei-Chiu Chuang | Stephen O’Donnell | 
| HDFS-14692 | Upload button should not encode complete url | Major | . | Lokesh Jain | Lokesh Jain | 
| HDFS-14631 | The DirectoryScanner doesn’t fix the wrongly placed replica. | Major | . | Jinglun | Jinglun | 
| YARN-9685 | NPE when rendering the info table of leaf queue in non-accessible partitions | Major | capacityscheduler | Tao Yang | Tao Yang | 
| HDFS-14459 | ClosedChannelException silently ignored in FsVolumeList.addBlockPool() | Major | datanode | Stephen O’Donnell | Stephen O’Donnell | 
| HDFS-13359 | DataXceiver hung due to the lock in FsDatasetImpl#getBlockInputStream | Major | datanode | Yiqun Lin | Yiqun Lin | 
| YARN-9451 | AggregatedLogsBlock shows wrong NM http port | Minor | nodemanager | Prabhu Joseph | Prabhu Joseph | 
| YARN-9723 | ApplicationPlacementContext is not required for terminated jobs during recovery | Major | resourcemanager | Prabhu Joseph | Prabhu Joseph | 
| HDFS-12914 | Block report leases cause missing blocks until next report | Critical | namenode | Daryn Sharp | Santosh Marella | 
| HDFS-14148 | HDFS OIV ReverseXML SnapshotSection parser throws exception when there are more than one snapshottable directory | Major | hdfs | Siyao Meng | Siyao Meng | 
| HDFS-14595 | HDFS-11848 breaks API compatibility | Blocker | . | Wei-Chiu Chuang | Siyao Meng | 
| HDFS-14423 | Percent (%) and plus (+) characters no longer work in WebHDFS | Major | webhdfs | Jing Wang | Masatake Iwasaki | 
| MAPREDUCE-7230 | TestHSWebApp.testLogsViewSingle fails | Major | jobhistoryserver, test | Prabhu Joseph | Prabhu Joseph | 
| HDFS-14687 | Standby Namenode never come out of safemode when EC files are being written. | Critical | ec, namenode | Surendra Singh Lilhore | Surendra Singh Lilhore | 
| HDFS-13101 | Yet another fsimage corruption related to snapshot | Major | snapshots | Yongjun Zhang | Shashikant Banerjee | 
| HDFS-13201 | Fix prompt message in testPolicyAndStateCantBeNull | Minor | . | chencan | chencan | 
| HDFS-14311 | Multi-threading conflict at layoutVersion when loading block pool storage | Major | rolling upgrades | Yicong Cai | Yicong Cai | 
| HDFS-14582 | Failed to start DN with ArithmeticException when NULL checksum used | Major | datanode | Surendra Singh Lilhore | Surendra Singh Lilhore | 
| HADOOP-16494 | Add SHA-256 or SHA-512 checksum to release artifacts to comply with the release distribution policy | Blocker | build | Akira Ajisaka | Akira Ajisaka | 
| YARN-9774 | Fix order of arguments for assertEquals in TestSLSUtils | Minor | test | Nikhil Navadiya | Nikhil Navadiya | 
| HDFS-13596 | NN restart fails after RollingUpgrade from 2.x to 3.x | Blocker | hdfs | Hanisha Koneru | Fei Hui | 
| HDFS-14396 | Failed to load image from FSImageFile when downgrade from 3.x to 2.x | Blocker | rolling upgrades | Fei Hui | Fei Hui | 
| YARN-9642 | Fix Memory Leak in AbstractYarnScheduler caused by timer | Blocker | resourcemanager | Bibin A Chundatt | Bibin A Chundatt | 
| HDFS-13977 | NameNode can kill itself if it tries to send too many txns to a QJM simultaneously | Major | namenode, qjm | Erik Krogen | Erik Krogen | 
| YARN-9438 | launchTime not written to state store for running applications | Major | . | Jonathan Hung | Jonathan Hung | 
| HDFS-12212 | Options.Rename.To_TRASH is considered even when Options.Rename.NONE is specified | Major | namenode | Vinayakumar B | Vinayakumar B | 
| HDFS-8178 | QJM doesn’t move aside stale inprogress edits files | Major | qjm | Zhe Zhang | Istvan Fajth | 
| HDFS-14706 | Checksums are not checked if block meta file is less than 7 bytes | Major | . | Stephen O’Donnell | Stephen O’Donnell | 
| YARN-9797 | LeafQueue#activateApplications should use resourceCalculator#fitsIn | Blocker | . | Bibin A Chundatt | Bilwa S T | 
| YARN-9785 | Fix DominantResourceCalculator when one resource is zero | Blocker | . | Bilwa S T | Bilwa S T | 
| YARN-9817 | Fix failing testcases due to not initialized AsyncDispatcher -  ArithmeticException: / by zero | Major | test | Prabhu Joseph | Prabhu Joseph |