HADOOP-9998. Provide methods to clear only part of the DNSToSwitchMapping. (Junping Du via Colin Patrick McCabe)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1526568 13f79535-47bb-0310-9956-ffa450edef68

Author: cmccabe

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -49,6 +49,9 @@ Release 2.3.0 - UNRELEASED
     HADOOP-9915.  o.a.h.fs.Stat support on Mac OS X  (Binglin Chang via Colin
     Patrick McCabe)
 
+    HADOOP-9998.  Provide methods to clear only part of the DNSToSwitchMapping.
+    (Junping Du via Colin Patrick McCabe)
+
   OPTIMIZATIONS
 
     HADOOP-9748. Reduce blocking on UGI.ensureInitialized (daryn)

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/CachedDNSToSwitchMapping.java

@@ -154,4 +154,11 @@ public boolean isSingleSwitch() {
   public void reloadCachedMappings() {
     cache.clear();
   }
+
+  @Override
+  public void reloadCachedMappings(List<String> names) {
+    for (String name : names) {
+      cache.remove(name);
+    }
+  }
 }

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/DNSToSwitchMapping.java

@@ -59,4 +59,12 @@ public interface DNSToSwitchMapping {
    * will get a chance to see the new data.
    */
   public void reloadCachedMappings();
+  
+  /**
+   * Reload cached mappings on specific nodes.
+   *
+   * If there is a cache on these nodes, this method will clear it, so that 
+   * future accesses will see updated data.
+   */
+  public void reloadCachedMappings(List<String> names);
 }

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/ScriptBasedMapping.java

@@ -269,5 +269,11 @@ public void reloadCachedMappings() {
       // Nothing to do here, since RawScriptBasedMapping has no cache, and
       // does not inherit from CachedDNSToSwitchMapping
     }
+
+    @Override
+    public void reloadCachedMappings(List<String> names) {
+      // Nothing to do here, since RawScriptBasedMapping has no cache, and
+      // does not inherit from CachedDNSToSwitchMapping
+    }
   }
 }

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/TableMapping.java

@@ -162,5 +162,12 @@ public void reloadCachedMappings() {
         }
       }
     }
+
+    @Override
+    public void reloadCachedMappings(List<String> names) {
+      // TableMapping has to reload all mappings at once, so no chance to 
+      // reload mappings on specific nodes
+      reloadCachedMappings();
+    }
   }
 }

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/net/StaticMapping.java

@@ -152,4 +152,10 @@ public void reloadCachedMappings() {
     // reloadCachedMappings does nothing for StaticMapping; there is
     // nowhere to reload from since all data is in memory.
   }
+
+  @Override
+  public void reloadCachedMappings(List<String> names) {
+    // reloadCachedMappings does nothing for StaticMapping; there is
+    // nowhere to reload from since all data is in memory.
+  }
 }

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/net/TestSwitchMapping.java

@@ -120,5 +120,9 @@ public List<String> resolve(List<String> names) {
     @Override
     public void reloadCachedMappings() {
     }
+
+    @Override
+    public void reloadCachedMappings(List<String> names) {
+    }
   }
 }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeManager.java

@@ -886,7 +886,12 @@ nodes with its data cleared (or user can just remove the StorageID
       // If the network location is invalid, clear the cached mappings
       // so that we have a chance to re-add this DataNode with the
       // correct network location later.
-      dnsToSwitchMapping.reloadCachedMappings();
+      List<String> invalidNodeNames = new ArrayList<String>(3);
+      // clear cache for nodes in IP or Hostname
+      invalidNodeNames.add(nodeReg.getIpAddr());
+      invalidNodeNames.add(nodeReg.getHostName());
+      invalidNodeNames.add(nodeReg.getPeerHostName());
+      dnsToSwitchMapping.reloadCachedMappings(invalidNodeNames);
       throw e;
     }
   }

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/test/java/org/apache/hadoop/mapreduce/v2/hs/TestJobHistoryParsing.java

@@ -99,6 +99,10 @@ public List<String> resolve(List<String> names) {
     @Override
     public void reloadCachedMappings() {
     }
+
+    @Override
+    public void reloadCachedMappings(List<String> names) {	
+    }
   }
 
   @Test(timeout = 50000)

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-client/src/test/java/org/apache/hadoop/yarn/client/api/impl/TestAMRMClientContainerRequest.java

@@ -215,6 +215,10 @@ public List<String> resolve(List<String> names) {
 
     @Override
     public void reloadCachedMappings() {}
+
+    @Override
+    public void reloadCachedMappings(List<String> names) {
+    }
   }
 
   private void verifyResourceRequest(