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18 package org.apache.hadoop.hbase.master;
19
20 import java.util.Arrays;
21 import java.util.List;
22
23 import org.apache.commons.logging.Log;
24 import org.apache.commons.logging.LogFactory;
25 import org.apache.hadoop.hbase.classification.InterfaceAudience;
26 import org.apache.hadoop.conf.Configuration;
27 import org.apache.hadoop.hbase.ServerName;
28 import org.apache.hadoop.hbase.util.ReflectionUtils;
29 import org.apache.hadoop.net.DNSToSwitchMapping;
30 import org.apache.hadoop.net.ScriptBasedMapping;
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36 @InterfaceAudience.Private
37 public class RackManager {
38 static final Log LOG = LogFactory.getLog(RackManager.class);
39 public static final String UNKNOWN_RACK = "Unknown Rack";
40
41 private DNSToSwitchMapping switchMapping;
42
43 public RackManager(Configuration conf) {
44 switchMapping = ReflectionUtils.instantiateWithCustomCtor(
45 conf.getClass("hbase.util.ip.to.rack.determiner", ScriptBasedMapping.class,
46 DNSToSwitchMapping.class).getName(), new Class<?>[]{Configuration.class},
47 new Object[]{conf});
48 }
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56 public String getRack(ServerName server) {
57 if (server == null) {
58 return UNKNOWN_RACK;
59 }
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62 List<String> racks = switchMapping.resolve(Arrays.asList(server.getHostname()));
63 if (racks != null && !racks.isEmpty()) {
64 return racks.get(0);
65 }
66
67 return UNKNOWN_RACK;
68 }
69 }