Bigdata

Hadoop requires OS-level user accounts on every cluster node regardless of security configuration. This post explains why, covering both secure and simple mode, and addresses whether the requirement can be removed.

A quick reference for updating a Cloudera Manager license through the REST API using a single curl command, including the required headers and authentication.

Cloudera Manager raises a timezone mismatch alert when the OS clock files disagree with the timezone CM expects. This post walks through the three key files to check and how to align them.

Hue does not provide a built-in UI option to remove user accounts. This workaround uses the Hue Django shell to delete one or more users directly from the database, with a clear caveat that the process is unsupported.

A quick reference for calculating the exact timeout window before Hadoop marks a Datanode as dead, based on the heartbeat and recheck-interval settings.

Specific JDK 1.8.0 builds (u40, u45, u91, u92) are known to break SPNEGO authentication and Hadoop web interfaces. This post documents the affected versions, the symptoms, and the recommended downgrade path.