[HBASE-14706] RegionLocationFinder should return multiple servernames by top host

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.2.0, 1.3.0, 2.0.0
• Fix Version/s: 1.2.0, 1.3.0, 1.1.3, 2.0.0
• Component/s: Balancer
• Hadoop Flags: Reviewed
• Assignee: Guanghao Zhang
• Reporter: Guanghao Zhang
• Created: 27/Oct/15 14:40
• Updated: 27/Jan/16 15:28
• Resolved: 06/Nov/15 14:18

Description

Multiple RS can run on the same host. But in current RegionLocationFinder, mapHostNameToServerName map one host to only one server. This will make LocalityCostFunction get wrong locality about region.

    // create a mapping from hostname to ServerName for fast lookup
    HashMap<String, ServerName> hostToServerName = new HashMap<String, ServerName>();
    for (ServerName sn : regionServers) {
      hostToServerName.put(sn.getHostname(), sn);
    }