Running Diagnostic Commands for Roles

You can run diagnostic utility tools such as "collect stack traces" and "heap dump" against most role processes.

Cloudera Manager allows administrators to run the following diagnostic utility tools against most Java-based role processes:
  • List Open Files (lsof) - Lists the open files of the process.
  • Collect Stack Traces (jstack) - Captures Java thread stack traces for the process.
  • Heap Dump (jmap) - Captures a heap dump for the process.
  • Heap Histogram (jmap -histo) - Produces a histogram of the heap for the process.

These commands are found on the Actions menu of the Cloudera Manager page for the instance of the role. For example, to run diagnostics commands for the HDFS active NameNode, perform these steps:

  1. Click the HDFS service on the Home > Status tab or select it on the Clusters menu.
  2. Click Instances > NameNode (Active).
  3. Click the Actions menu.
  4. Choose one of the diagnostics commands listed in the lower section of the menu.
  5. Click the button in the confirmation dialog box to confirm your choice.
  6. When the command is executed, click Download Result Data and save the file to view the command output.