Known Issues in HDFS

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

CDPSDX-5302: Avoiding long delay on the HBase master does not happen during upgrade.
  1. Log in to Cloudera Manager
  2. Select the HDFS service
  3. Select Configurations tab
  4. Search for hdfs-site.xml.
  5. Set ipc.client.connect.timeout = 5000
  6. Set ipc.client.connect.max.retries.on.timeouts = 5
  7. Click Save
The above configuration changes ensures that:
  1. The long delay on the HBase master does not happen during upgrade.
  2. The long delay on the HBase master recovery does not happen during upgrade.
CDPD-65530: HDFS requests throw UnknownHostException during OS upgrade
During the VM replacement as part of OS upgrade, every new node gets a new IP Address, and if the old IP address is cached somewhere, HDFS requests fail with UnknownHostException and it recovers after sometime (10 mins max).

The issue is seen during COD and DL ZDU.

CDPD-67230: Rolling restart can cause failed writes on small clusters
In a rolling restart, if the cluster has less than 10 datanodes existing writers can fail with an error indicating a new block cannot be allocated and all nodes are excluded. This is because the client has attempted to use all the datanodes in the cluster, and failed to write to each of them as they were restarted. This will only happen on small clusters of less than 10 datanodes, as larger clusters have more spare node to allow the write to continue.
OPSAPS-55788: WebHDFS is always enabled. The Enable WebHDFS checkbox does not take effect.
Unsupported Features
The following HDFS features are currently not supported in Cloudera Data Platform: