HDFS-12486. GetConf to get journalnodeslist. Contributed by Bharat Viswanadham.

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSUtilClient.java

@@ -406,7 +406,7 @@ static Map<String, InetSocketAddress> getAddressesForNameserviceId(
    * @param keys list of keys in the order of preference
    * @return value of the key or default if a key was not found in configuration
    */
-  private static String getConfValue(String defaultValue, String keySuffix,
+  public static String getConfValue(String defaultValue, String keySuffix,
       Configuration conf, String... keys) {
     String value = null;
     for (String key : keys) {

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

@@ -31,6 +31,7 @@
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_RPC_ADDRESS_KEY;
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_SECONDARY_HTTP_ADDRESS_KEY;
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_SERVICE_RPC_ADDRESS_KEY;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_SHARED_EDITS_DIR_KEY;
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMESERVICE_ID;
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_SERVER_HTTPS_KEYPASSWORD_KEY;
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_SERVER_HTTPS_KEYSTORE_PASSWORD_KEY;
@@ -44,6 +45,8 @@
 import java.net.InetSocketAddress;
 import java.net.URI;
 import java.net.URISyntaxException;
+import java.net.UnknownHostException;
+
 import java.security.SecureRandom;
 import java.util.Arrays;
 import java.util.Collection;
@@ -74,6 +77,7 @@
 import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.security.token.delegation.DelegationTokenIdentifier;
 import org.apache.hadoop.hdfs.server.common.HdfsServerConstants;
+import org.apache.hadoop.hdfs.server.common.Util;
 import org.apache.hadoop.hdfs.server.namenode.NameNode;
 import org.apache.hadoop.http.HttpConfig;
 import org.apache.hadoop.http.HttpServer2;
@@ -453,6 +457,85 @@ public static Set<String> getAllNnPrincipals(Configuration conf) throws IOExcept
     return principals;
   }
 
+  /**
+   * Returns list of Journalnode addresses from the configuration.
+   *
+   * @param conf configuration
+   * @return list of journalnode host names
+   * @throws URISyntaxException
+   * @throws IOException
+   */
+  public static Set<String> getJournalNodeAddresses(
+      Configuration conf) throws URISyntaxException, IOException {
+    Set<String> journalNodeList = new HashSet<>();
+    String journalsUri = "";
+    try {
+      journalsUri = conf.get(DFS_NAMENODE_SHARED_EDITS_DIR_KEY);
+      if (journalsUri == null) {
+        Collection<String> nameserviceIds = DFSUtilClient.
+            getNameServiceIds(conf);
+        for (String nsId : nameserviceIds) {
+          journalsUri = DFSUtilClient.getConfValue(
+              null, nsId, conf, DFS_NAMENODE_SHARED_EDITS_DIR_KEY);
+          if (journalsUri == null) {
+            Collection<String> nnIds = DFSUtilClient.getNameNodeIds(conf, nsId);
+            for (String nnId : nnIds) {
+              String suffix = DFSUtilClient.concatSuffixes(nsId, nnId);
+              journalsUri = DFSUtilClient.getConfValue(
+                  null, suffix, conf, DFS_NAMENODE_SHARED_EDITS_DIR_KEY);
+              if (journalsUri == null ||
+                  !journalsUri.startsWith("qjournal://")) {
+                return journalNodeList;
+              } else {
+                LOG.warn(DFS_NAMENODE_SHARED_EDITS_DIR_KEY +" is to be " +
+                    "configured as nameservice" +
+                    " specific key(append it with nameserviceId), no need" +
+                    " to append it with namenodeId");
+                URI uri = new URI(journalsUri);
+                List<InetSocketAddress> socketAddresses = Util.
+                    getAddressesList(uri);
+                for (InetSocketAddress is : socketAddresses) {
+                  journalNodeList.add(is.getHostName());
+                }
+              }
+            }
+          } else if (!journalsUri.startsWith("qjournal://")) {
+            return journalNodeList;
+          } else {
+            URI uri = new URI(journalsUri);
+            List<InetSocketAddress> socketAddresses = Util.
+                getAddressesList(uri);
+            for (InetSocketAddress is : socketAddresses) {
+              journalNodeList.add(is.getHostName());
+            }
+          }
+        }
+      } else {
+        if (!journalsUri.startsWith("qjournal://")) {
+          return journalNodeList;
+        } else {
+          URI uri = new URI(journalsUri);
+          List<InetSocketAddress> socketAddresses = Util.getAddressesList(uri);
+          for (InetSocketAddress is : socketAddresses) {
+            journalNodeList.add(is.getHostName());
+          }
+        }
+      }
+    } catch(UnknownHostException e) {
+      LOG.error("The conf property " + DFS_NAMENODE_SHARED_EDITS_DIR_KEY
+          + " is not properly set with correct journal node hostnames");
+      throw new UnknownHostException(journalsUri);
+    } catch(URISyntaxException e)  {
+      LOG.error("The conf property " + DFS_NAMENODE_SHARED_EDITS_DIR_KEY
+          + "is not set properly with correct journal node uri");
+      throw new URISyntaxException(journalsUri, "The conf property " +
+          DFS_NAMENODE_SHARED_EDITS_DIR_KEY + "is not" +
+          " properly set with correct journal node uri");
+    }
+
+    return journalNodeList;
+  }
+
   /**
    * Returns list of InetSocketAddress corresponding to  backup node rpc 
    * addresses from the configuration.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/GetConf.java

@@ -20,11 +20,13 @@
 import java.io.IOException;
 import java.io.PrintStream;
 import java.net.InetSocketAddress;
+import java.net.URISyntaxException;
 import java.security.PrivilegedExceptionAction;
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 import org.apache.hadoop.HadoopIllegalArgumentException;
 import org.apache.hadoop.conf.Configuration;
@@ -68,6 +70,7 @@ enum Command {
     SECONDARY("-secondaryNameNodes", 
         "gets list of secondary namenodes in the cluster."),
     BACKUP("-backupNodes", "gets list of backup nodes in the cluster."),
+    JOURNALNODE("-journalNodes", "gets list of journal nodes in the cluster."),
     INCLUDE_FILE("-includeFile",
         "gets the include file path that defines the datanodes " +
         "that can join the cluster."),
@@ -86,6 +89,8 @@ enum Command {
           new SecondaryNameNodesCommandHandler());
       map.put(StringUtils.toLowerCase(BACKUP.getName()),
           new BackupNodesCommandHandler());
+      map.put(StringUtils.toLowerCase(JOURNALNODE.getName()),
+          new JournalNodeCommandHandler());
       map.put(StringUtils.toLowerCase(INCLUDE_FILE.getName()),
           new CommandHandler(DFSConfigKeys.DFS_HOSTS));
       map.put(StringUtils.toLowerCase(EXCLUDE_FILE.getName()),
@@ -203,6 +208,18 @@ public int doWorkInternal(GetConf tool, String []args) throws IOException {
     }
   }
 
+  /**
+   * Handler for {@linke Command#JOURNALNODE}.
+   */
+  static class JournalNodeCommandHandler extends CommandHandler {
+    @Override
+    public int doWorkInternal(GetConf tool, String[] args)
+        throws URISyntaxException, IOException {
+      tool.printSet(DFSUtil.getJournalNodeAddresses(tool.getConf()));
+      return 0;
+    }
+  }
+
   /**
    * Handler for {@link Command#SECONDARY}
    */
@@ -288,6 +305,18 @@ void printMap(Map<String, Map<String, InetSocketAddress>> map) {
     printOut(buffer.toString());
   }
 
+  void printSet(Set<String> journalnodes) {
+    StringBuilder buffer = new StringBuilder();
+
+    for (String journalnode : journalnodes) {
+      if (buffer.length() > 0) {
+        buffer.append(" ");
+      }
+      buffer.append(journalnode);
+    }
+    printOut(buffer.toString());
+  }
+
   private void printUsage() {
     printError(USAGE);
   }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/tools/TestGetConf.java

@@ -23,7 +23,10 @@
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_RPC_ADDRESS_KEY;
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_SECONDARY_HTTP_ADDRESS_KEY;
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_SERVICE_RPC_ADDRESS_KEY;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_SHARED_EDITS_DIR_KEY;
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMESERVICES;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_HA_NAMENODES_KEY_PREFIX;
+
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
@@ -33,10 +36,14 @@
 import java.io.IOException;
 import java.io.PrintStream;
 import java.net.InetSocketAddress;
+import java.net.URISyntaxException;
+import java.net.UnknownHostException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
+import java.util.HashSet;
+import java.util.Set;
 import java.util.StringTokenizer;
 
 import org.apache.hadoop.fs.FileSystem;
@@ -58,7 +65,7 @@
  */
 public class TestGetConf {
   enum TestType {
-    NAMENODE, BACKUP, SECONDARY, NNRPCADDRESSES
+    NAMENODE, BACKUP, SECONDARY, NNRPCADDRESSES, JOURNALNODE
   }
   FileSystem localFileSys; 
   /** Setup federation nameServiceIds in the configuration */
@@ -96,9 +103,10 @@ private String[] setupAddress(HdfsConfiguration conf, String key,
    * Add namenodes to the static resolution list to avoid going
    * through DNS which can be really slow in some configurations.
    */
-  private void setupStaticHostResolution(int nameServiceIdCount) {
+  private void setupStaticHostResolution(int nameServiceIdCount,
+                                         String hostname) {
     for (int i = 0; i < nameServiceIdCount; i++) {
-      NetUtils.addStaticResolution("nn" + i, "localhost");
+      NetUtils.addStaticResolution(hostname + i, "localhost");
     }
   }
 
@@ -173,6 +181,8 @@ private String getAddressListFromTool(TestType type, HdfsConfiguration conf,
     case NNRPCADDRESSES:
       args[0] = Command.NNRPCADDRESSES.getName();
       break;
+    case JOURNALNODE:
+      args[0] = Command.JOURNALNODE.getName();
     }
     return runTool(conf, args, success);
   }
@@ -321,7 +331,7 @@ public void testFederation() throws Exception {
     String[] nnAddresses = setupAddress(conf,
         DFS_NAMENODE_SERVICE_RPC_ADDRESS_KEY, nsCount, 1000);
     setupAddress(conf, DFS_NAMENODE_RPC_ADDRESS_KEY, nsCount, 1500);
-    setupStaticHostResolution(nsCount);
+    setupStaticHostResolution(nsCount, "nn");
     String[] backupAddresses = setupAddress(conf,
         DFS_NAMENODE_BACKUP_ADDRESS_KEY, nsCount, 2000);
     String[] secondaryAddresses = setupAddress(conf,
@@ -349,6 +359,159 @@ public void testFederation() throws Exception {
     verifyAddresses(conf, TestType.NNRPCADDRESSES, true, nnAddresses);
   }
 
+  /**
+   * Tests for journal node addresses.
+   * @throws Exception
+   */
+  @Test(timeout=10000)
+  public void testGetJournalNodes() throws Exception {
+
+    final int nsCount = 3;
+    final String journalsBaseUri = "qjournal://jn0:9820;jn1:9820;jn2:9820";
+    setupStaticHostResolution(nsCount, "jn");
+
+    // With out Name service Id
+    HdfsConfiguration conf = new HdfsConfiguration(false);
+    conf.set(DFS_NAMENODE_SHARED_EDITS_DIR_KEY,
+        journalsBaseUri+"/");
+
+    Set<String> expected = new HashSet<>();
+    expected.add("jn0");
+    expected.add("jn1");
+    expected.add("jn2");
+
+    String expected1 = "";
+    StringBuilder buffer = new StringBuilder();
+    for (String val : expected) {
+      if (buffer.length() > 0) {
+        buffer.append(" ");
+      }
+      buffer.append(val);
+    }
+    buffer.append("\n");
+    expected1 = buffer.toString();
+
+    Set<String> actual = DFSUtil.getJournalNodeAddresses(conf);
+    assertEquals(expected.toString(), actual.toString());
+
+    String actual1 = getAddressListFromTool(TestType.JOURNALNODE,
+        conf, true);
+    assertEquals(expected1, actual1);
+    conf.clear();
+
+    //With out Name service Id
+    conf.set(DFS_NAMENODE_SHARED_EDITS_DIR_KEY,
+        journalsBaseUri + "/");
+
+    actual = DFSUtil.getJournalNodeAddresses(conf);
+    assertEquals(expected.toString(), actual.toString());
+
+    actual1 = getAddressListFromTool(TestType.JOURNALNODE,
+        conf, true);
+    assertEquals(expected1, actual1);
+    conf.clear();
+
+
+    //Federation with HA, but suffixed only with Name service Id
+    setupNameServices(conf, nsCount);
+    conf.set(DFS_HA_NAMENODES_KEY_PREFIX +".ns0",
+        "nn0,nn1");
+    conf.set(DFS_HA_NAMENODES_KEY_PREFIX +".ns1",
+        "nn0, nn1");
+    conf.set(DFS_NAMENODE_SHARED_EDITS_DIR_KEY+".ns0",
+        journalsBaseUri + "/ns0");
+    conf.set(DFS_NAMENODE_SHARED_EDITS_DIR_KEY+".ns1",
+        journalsBaseUri + "/ns1");
+
+    actual = DFSUtil.getJournalNodeAddresses(conf);
+    assertEquals(expected.toString(), actual.toString());
+
+    expected1 = getAddressListFromTool(TestType.JOURNALNODE,
+        conf, true);
+    assertEquals(expected1, actual1);
+
+    conf.clear();
+
+
+    // Federation with HA
+    setupNameServices(conf, nsCount);
+    conf.set(DFS_HA_NAMENODES_KEY_PREFIX + ".ns0", "nn0,nn1");
+    conf.set(DFS_HA_NAMENODES_KEY_PREFIX + ".ns1", "nn0, nn1");
+    conf.set(DFS_NAMENODE_SHARED_EDITS_DIR_KEY + ".ns0.nn0",
+        journalsBaseUri + "/ns0");
+    conf.set(DFS_NAMENODE_SHARED_EDITS_DIR_KEY + ".ns0.nn1",
+        journalsBaseUri + "/ns0");
+    conf.set(DFS_NAMENODE_SHARED_EDITS_DIR_KEY + ".ns1.nn2",
+        journalsBaseUri + "/ns1");
+    conf.set(DFS_NAMENODE_SHARED_EDITS_DIR_KEY + ".ns1.nn3",
+        journalsBaseUri + "/ns1");
+
+    actual = DFSUtil.getJournalNodeAddresses(conf);
+    assertEquals(expected.toString(), actual.toString());
+
+    actual1 = getAddressListFromTool(TestType.JOURNALNODE,
+        conf, true);
+    assertEquals(expected1, actual1);
+
+    conf.clear();
+
+    // Name service setup, but no journal node
+    setupNameServices(conf, nsCount);
+
+    expected = new HashSet<>();
+    actual = DFSUtil.getJournalNodeAddresses(conf);
+    assertEquals(expected.toString(), actual.toString());
+
+    actual1 = "\n";
+    expected1 = getAddressListFromTool(TestType.JOURNALNODE,
+        conf, true);
+    assertEquals(expected1, actual1);
+    conf.clear();
+
+    //name node edits dir is present, but set
+    //to location of storage shared directory
+    conf.set(DFS_NAMENODE_SHARED_EDITS_DIR_KEY,
+        "file:///mnt/filer1/dfs/ha-name-dir-shared");
+
+    expected = new HashSet<>();
+    actual = DFSUtil.getJournalNodeAddresses(conf);
+    assertEquals(expected.toString(), actual.toString());
+
+    expected1 = getAddressListFromTool(TestType.JOURNALNODE,
+        conf, true);
+    actual1 = "\n";
+    assertEquals(expected1, actual1);
+    conf.clear();
+  }
+
+  /*
+   ** Test for unknown journal node host exception.
+  */
+  @Test(expected = UnknownHostException.class, timeout = 10000)
+  public void testUnknownJournalNodeHost()
+      throws URISyntaxException, IOException {
+    String journalsBaseUri = "qjournal://jn1:9820;jn2:9820;jn3:9820";
+    HdfsConfiguration conf = new HdfsConfiguration(false);
+    conf.set(DFS_NAMENODE_SHARED_EDITS_DIR_KEY,
+        journalsBaseUri + "/jndata");
+    DFSUtil.getJournalNodeAddresses(conf);
+  }
+
+  /*
+   ** Test for malformed journal node urisyntax exception.
+  */
+  @Test(expected = URISyntaxException.class, timeout = 10000)
+  public void testJournalNodeUriError()
+      throws URISyntaxException, IOException {
+    final int nsCount = 3;
+    String journalsBaseUri = "qjournal://jn0 :9820;jn1:9820;jn2:9820";
+    setupStaticHostResolution(nsCount, "jn");
+    HdfsConfiguration conf = new HdfsConfiguration(false);
+    conf.set(DFS_NAMENODE_SHARED_EDITS_DIR_KEY,
+        journalsBaseUri + "/jndata");
+    DFSUtil.getJournalNodeAddresses(conf);
+  }
+
   @Test(timeout=10000)
   public void testGetSpecificKey() throws Exception {
     HdfsConfiguration conf = new HdfsConfiguration();
@@ -422,7 +585,7 @@ public void testIncludeInternalNameServices() throws Exception {
     setupAddress(conf, DFS_NAMENODE_SERVICE_RPC_ADDRESS_KEY, nsCount, 1000);
     setupAddress(conf, DFS_NAMENODE_RPC_ADDRESS_KEY, nsCount, 1500);
     conf.set(DFS_INTERNAL_NAMESERVICES_KEY, "ns1");
-    setupStaticHostResolution(nsCount);
+    setupStaticHostResolution(nsCount, "nn");
 
     String[] includedNN = new String[] {"nn1:1001"};
     verifyAddresses(conf, TestType.NAMENODE, false, includedNN);