Known Issues in HDFS
Learn about the known issues in HDFS, the impact or changes to the functionality, and the workaround.
- CDPD-28459: After performing an upgrade rollback from CDP 7.1.7 to CDH6, you may see the following error when restarting the DataNodes: ERROR datanode.DataNode: Exception in secureMain java.io.IOException: The path component: '/var/run/hdfs-sockets' in '/var/run/hdfs-sockets/dn' has permissions 0755 uid 39998 and gid 1006. It is not protected because it is owned by a user who is not root and not the effective user: '0'.
- You must run the command described in the error message "chown root /var/run/hdfs-sockets". After this, the DataNode will restart successfully.
- CDPD-28390: Rolling restart of the HDFS JournalNodes may time out on Ubuntu20.
- If the restart operation times out, you can manually stop and restart the Name Node and Journal Node services one by one.
- OPSAPS-60832: When decommission of DN runs for a longer time and when decommission monitor's kerberos ticket expires, it is not auto-renewed. Decommission of DN is not completed in CM as decommission monitor fails to fetch the state of DN after kerberos ticket expiry.
- Decommission state of DN can be fetched using CLI command, i.e, hdfs dfsadmin -report.
- 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)