[HDFS-15120] Refresh BlockPlacementPolicy at runtime.

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.3.0
• Hadoop Flags: Reviewed
• Assignee: Jinglun
• Reporter: Jinglun
• Created: 14/Jan/20 04:44
• Updated: 06/Mar/20 09:33
• Resolved: 26/Feb/20 21:14

Description

Now if we want to switch BlockPlacementPolicies we need to restart the NameNode. It would be convenient if we can switch it at runtime. For example we can switch between AvailableSpaceBlockPlacementPolicy and BlockPlacementPolicyDefault as needed.