[HDFS-10813] DiskBalancer: Add the getNodeList method in Command

• Type: Sub-task
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 2.9.0, 3.0.0-alpha2
• Component/s: balancer & mover
• Hadoop Flags: Reviewed
• Assignee: Yiqun Lin
• Reporter: Yiqun Lin
• Created: 29/Aug/16 10:16
• Updated: 02/Sep/16 21:43
• Resolved: 31/Aug/16 01:46

Description

The method Command#getNodeList in DiskBalancer was added in HDFS-9545, but it's never used. We can improve that in the following aspects:

1.Change private to protected so that the subclass can use that method in the future.
2.Reuse the method Command#getNodeList and to construct a new method
like this List<DiskBalancerDataNode> getNodes(String listArg). This method can be used for getting multiple nodes in the future. For example, if we want to use hdfs diskbalancer -report -node or hdfs diskbalancer -plan with multiple specified nodes, that method can be used. Now these commands only support one node.