[YARN-9332] RackResolver tool should accept multiple hosts

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.9.2, 3.0.3, 2.8.5, 2.7.7, 3.1.2
• Fix Version/s: 3.3.0, 3.2.1
• Component/s: yarn
• Hadoop Flags: Reviewed
• Assignee: Lantao Jin
• Reporter: Lantao Jin
• Created: 26/Feb/19 09:14
• Updated: 18/Mar/19 07:03
• Resolved: 02/Mar/19 15:36

Description

RackResolver as a public rack resolver tool only offers a method public static Node resolve(String hostName) which only accepts one host a time. Actually the internal implementation class DNSToSwitchMapping always accept a host list as its input and return a list of resolved racks. That's cause the invoker like Spark takes a long time to resolve the rack info when handling abundant tasks (a mass of loops to execute script to resolve rack info).

Issue Links

• relates to: YARN-9394 Use new API of RackResolver to get better performance