HDFS-2934. Allow configs to be scoped to all NNs in the nameservice. Contributed by Todd Lipcon.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/HDFS-1623@1244759 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES.HDFS-1623.txt

@@ -204,3 +204,5 @@ HDFS-2942. TestActiveStandbyElectorRealZK fails if build dir does not exist. (at
 HDFS-2948. NN throws NPE during shutdown if it fails to startup (todd)
 
 HDFS-2909. HA: Inaccessible shared edits dir not getting removed from FSImage storage dirs upon error. (Bikas Saha via jitendra)
+
+HDFS-2934. Allow configs to be scoped to all NNs in the nameservice. (todd)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSUtil.java

@@ -746,7 +746,10 @@ public class DFSUtil {
   /**
    * Sets the node specific setting into generic configuration key. Looks up
    * value of "key.nameserviceId.namenodeId" and if found sets that value into 
-   * generic key in the conf. Note that this only modifies the runtime conf.
+   * generic key in the conf. If this is not found, falls back to
+   * "key.nameserviceId" and then the unmodified key.
+   *
+   * Note that this only modifies the runtime conf.
    * 
    * @param conf
    *          Configuration object to lookup specific key and to set the value
@@ -764,6 +767,11 @@ public class DFSUtil {
       String nameserviceId, String nnId, String... keys) {
     for (String key : keys) {
       String value = conf.get(addKeySuffixes(key, nameserviceId, nnId));
+      if (value != null) {
+        conf.set(key, value);
+        continue;
+      }
+      value = conf.get(addKeySuffixes(key, nameserviceId));
       if (value != null) {
         conf.set(key, value);
       }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSUtil.java

@@ -325,6 +325,39 @@ public class TestDFSUtil {
     }
   }
 
+  /**
+   * Regression test for HDFS-2934.
+   */
+  @Test
+  public void testSomeConfsNNSpecificSomeNSSpecific() {
+    final HdfsConfiguration conf = new HdfsConfiguration();
+
+    String key = DFSConfigKeys.DFS_NAMENODE_SHARED_EDITS_DIR_KEY;
+    conf.set(key, "global-default");
+    conf.set(key + ".ns1", "ns1-override");
+    conf.set(key + ".ns1.nn1", "nn1-override");
+
+    // A namenode in another nameservice should get the global default.
+    Configuration newConf = new Configuration(conf);
+    NameNode.initializeGenericKeys(newConf, "ns2", "nn1");
+    assertEquals("global-default", newConf.get(key));
+    
+    // A namenode in another non-HA nameservice should get global default.
+    newConf = new Configuration(conf);
+    NameNode.initializeGenericKeys(newConf, "ns2", null);
+    assertEquals("global-default", newConf.get(key));    
+    
+    // A namenode in the same nameservice should get the ns setting
+    newConf = new Configuration(conf);
+    NameNode.initializeGenericKeys(newConf, "ns1", "nn2");
+    assertEquals("ns1-override", newConf.get(key));    
+
+    // The nn with the nn-specific setting should get its own override
+    newConf = new Configuration(conf);
+    NameNode.initializeGenericKeys(newConf, "ns1", "nn1");
+    assertEquals("nn1-override", newConf.get(key));    
+  }
+  
   /**
    * Tests for empty configuration, an exception is thrown from
    * {@link DFSUtil#getNNServiceRpcAddresses(Configuration)}