[HDDS-2116] Create SCMPipelineAllocationManager as background thread for pipeline creation

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Duplicate
• Fix Version/s: 0.5.0
• Release Note: Found duplicated.
• Assignee: Li Cheng
• Reporter: Li Cheng
• Created: 12/Sep/19 08:24
• Updated: 14/Apr/20 04:15
• Resolved: 11/Dec/19 09:42

Description

SCMAllocationManager can be leveraged to get a candidate set of datanodes based on placement policies. And it should make the pipeline creation process to be async and multi-thread. This should be done when we encounter with performance bottleneck in terms of pipeline creation.