Known Issues in HDFS

Learn about the known issues in HDFS, the impact or changes to the functionality, and the workaround.

OPSAPS-55788: WebHDFS is always enabled. The Enable WebHDFS checkbox does not take effect.: None.
Unsupported Features: The following HDFS features are currently not supported in Cloudera Data Platform:

ACLs for the NFS gateway (HADOOP-11004)

Aliyun Cloud Connector (HADOOP-12756)

Allow HDFS block replicas to be provided by an external storage system (HDFS-9806)

Consistent standby Serving reads (HDFS-12943)

Cost-Based RPC FairCallQueue (HDFS-14403)

HDFS Router Based Federation (HDFS-10467)

More than two NameNodes (HDFS-6440)

NameNode Federation (HDFS-1052)

NameNode Port-based Selective Encryption (HDFS-13541)

Non-Volatile Storage Class Memory (SCM) in HDFS Cache Directives (HDFS-13762)

OpenStack Swift (HADOOP-8545)

SFTP FileSystem (HADOOP-5732)

Storage policy satisfier (HDFS-10285)

Technical Service Bulletins

TSB 2021-531: HDFS Namenode checkpoints not running after installing or upgrading to CDP 7.1.7 in a TLS enabled cluster: HDFS Namenode checkpoints will not run correctly after installing or upgrading to CDP 7.1.7 in a TLS enabled cluster. Recent CDP Public Cloud releases are also affected, see full list of affected CDP releases below.; In an HDFS cluster with High Availability, the Standby NameNode (SBN) is responsible for periodically generating a new checkpoint (also called an FsImage). The standby NameNode then uploads this checkpoint to the Active NameNode (ANN). The purpose of the checkpoint is to reduce the NameNode’s startup time by reducing the number of edit logs that must be replayed on NameNode restart.; The image upload from the SBN to ANN is performed over the HTTP protocol using an embedded Jetty HTTP server in the ANN. Due to a bug in the Jetty version 9.4.39 shipped with CDP, this checkpoint upload can fail and the ANN will not receive new FsImage files. The following error is seen in the SBN service logs.
java.io.IOException: Exception during image upload
Knowledge article: For the latest update on this issue see the corresponding Knowledge article: TSB 2021-531: HDFS Namenode checkpoints not running after installing or upgrading to CDP 7.1.7 in a TLS enabled cluster

TSB 2023-666: Out of order HDFS snapshot deletion may delete renamed/moved files, which may result in data loss: Cloudera has discovered a bug in the Apache Hadoop Distributed File System (HDFS) snapshot implementation. Deleting an HDFS snapshot may incorrectly remove files in the .Trash directories or remove renamed files from the current file system state. This is an unexpected behavior because deleting an HDFS snapshot should only delete the files stored in the specified snapshot, but not data in the current state.; In the particular HDFS installation in which the bug was discovered, deleting one of the snapshots caused certain files to be moved to trash and deletion of some of the files in a .Trash directory. Although it is clear that the conditions of the bug are (1) out-of-order snapshot deletion and (2) files moved to trash or other directories, we were unable to replicate the bug in other HDFS installations after executing similar test operations with a variety of different sequences. We also did not observe any actual data loss in our tests. However, there is a remote possibility that this bug may lead to data loss.
Knowledge article: For the latest update on this issue see the corresponding Knowledge article: TSB 2023-666: Out of order HDFS snapshot deletion may delete renamed/moved files, which may result in data loss