[HDFS-15932] Improve the balancer error message when process exits abnormally.

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.3.1, 3.4.0, 3.2.3
• Fix Version/s: 3.3.1, 3.4.0, 3.2.3
• Component/s: balancer
• Target Version/s: 3.3.1, 3.4.0, 3.2.3
• Hadoop Flags: Reviewed
• Assignee: Renukaprasad C
• Reporter: Renukaprasad C
• Created: 29/Mar/21 11:13
• Updated: 11/Feb/24 08:52
• Resolved: 31/Mar/21 04:31

Description

The HDFS balancer exits abnormally. The content of the pid file is not cleaned up, and the new balancer cannot be started.

Start the balancer (start-balancer.sh threshold 5)
Kill the balancer process (kill -9 <Balancer PID>)
Re-execute the balancer, there will be an error message.
– Balancer is running as process xxxx. Stop it first.
(But process already stopped, error message can be more detailed)