HDFS-5752. Add a new DFSAdmin command to query, start and finalize rolling upgrade.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/HDFS-5535@1558299 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES_HDFS-5535.txt

@@ -4,3 +4,6 @@ HDFS-5535 subtasks:
     jing9)
 
     HDFS-5645. Support upgrade marker in editlog streams. (szetszwo)
+
+    HDFS-5752. Add a new DFSAdmin command to query, start and finalize rolling
+    upgrade. (szetszwo)

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

@@ -124,11 +124,13 @@ import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
 import org.apache.hadoop.hdfs.protocol.HdfsBlocksMetadata;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.DatanodeReportType;
+import org.apache.hadoop.hdfs.protocol.HdfsConstants.RollingUpgradeAction;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.SafeModeAction;
 import org.apache.hadoop.hdfs.protocol.HdfsFileStatus;
 import org.apache.hadoop.hdfs.protocol.LocatedBlock;
 import org.apache.hadoop.hdfs.protocol.LocatedBlocks;
 import org.apache.hadoop.hdfs.protocol.NSQuotaExceededException;
+import org.apache.hadoop.hdfs.protocol.RollingUpgradeInfo;
 import org.apache.hadoop.hdfs.protocol.SnapshotAccessControlException;
 import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport;
 import org.apache.hadoop.hdfs.protocol.SnapshottableDirectoryStatus;
@@ -2450,6 +2452,10 @@ public class DFSClient implements java.io.Closeable {
     namenode.finalizeUpgrade();
   }
 
+  RollingUpgradeInfo rollingUpgrade(RollingUpgradeAction action) throws IOException {
+    return namenode.rollingUpgrade(action);
+  }
+
   /**
    */
   @Deprecated

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

@@ -59,6 +59,7 @@ import org.apache.hadoop.hdfs.client.HdfsAdmin;
 import org.apache.hadoop.hdfs.client.HdfsDataInputStream;
 import org.apache.hadoop.hdfs.client.HdfsDataOutputStream;
 import org.apache.hadoop.hdfs.protocol.CacheDirectiveEntry;
+import org.apache.hadoop.hdfs.protocol.CacheDirectiveInfo;
 import org.apache.hadoop.hdfs.protocol.CachePoolEntry;
 import org.apache.hadoop.hdfs.protocol.CachePoolInfo;
 import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
@@ -66,11 +67,12 @@ import org.apache.hadoop.hdfs.protocol.DirectoryListing;
 import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.DatanodeReportType;
+import org.apache.hadoop.hdfs.protocol.HdfsConstants.RollingUpgradeAction;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.SafeModeAction;
 import org.apache.hadoop.hdfs.protocol.HdfsFileStatus;
 import org.apache.hadoop.hdfs.protocol.HdfsLocatedFileStatus;
 import org.apache.hadoop.hdfs.protocol.LocatedBlock;
-import org.apache.hadoop.hdfs.protocol.CacheDirectiveInfo;
+import org.apache.hadoop.hdfs.protocol.RollingUpgradeInfo;
 import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport;
 import org.apache.hadoop.hdfs.protocol.SnapshottableDirectoryStatus;
 import org.apache.hadoop.hdfs.security.token.block.InvalidBlockTokenException;
@@ -991,6 +993,14 @@ public class DistributedFileSystem extends FileSystem {
     dfs.finalizeUpgrade();
   }
 
+  /**
+   * Rolling upgrade: start/finalize/query.
+   */
+  public RollingUpgradeInfo rollingUpgrade(RollingUpgradeAction action)
+      throws IOException {
+    return dfs.rollingUpgrade(action);
+  }
+
   /*
    * Requests the namenode to dump data strcutures into specified 
    * file.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/ClientProtocol.java

@@ -36,6 +36,7 @@ import org.apache.hadoop.fs.ParentNotDirectoryException;
 import org.apache.hadoop.fs.UnresolvedLinkException;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.hdfs.DFSConfigKeys;
+import org.apache.hadoop.hdfs.protocol.HdfsConstants.RollingUpgradeAction;
 import org.apache.hadoop.hdfs.security.token.block.DataEncryptionKey;
 import org.apache.hadoop.hdfs.security.token.delegation.DelegationTokenIdentifier;
 import org.apache.hadoop.hdfs.security.token.delegation.DelegationTokenSelector;
@@ -760,6 +761,15 @@ public interface ClientProtocol {
   @Idempotent
   public void finalizeUpgrade() throws IOException;
 
+  /**
+   * Rolling upgrade operations.
+   * @param action either query, start or finailze.
+   * @return rolling upgrade information.
+   */
+  @Idempotent
+  public RollingUpgradeInfo rollingUpgrade(RollingUpgradeAction action)
+      throws IOException;
+
   /**
    * @return CorruptFileBlocks, containing a list of corrupt files (with
    *         duplicates if there is more than one corrupt block in a file)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/HdfsConstants.java

@@ -17,6 +17,9 @@
  */
 package org.apache.hadoop.hdfs.protocol;
 
+import java.util.HashMap;
+import java.util.Map;
+
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.hdfs.DFSConfigKeys;
@@ -78,6 +81,24 @@ public class HdfsConstants {
     SAFEMODE_LEAVE, SAFEMODE_ENTER, SAFEMODE_GET;
   }
 
+  public static enum RollingUpgradeAction {
+    QUERY, START, FINALIZE;
+    
+    private static final Map<String, RollingUpgradeAction> MAP
+        = new HashMap<String, RollingUpgradeAction>();
+    static {
+      MAP.put("", QUERY);
+      for(RollingUpgradeAction a : values()) {
+        MAP.put(a.name(), a);
+      }
+    }
+
+    /** Covert the given String to a RollingUpgradeAction. */
+    public static RollingUpgradeAction fromString(String s) {
+      return MAP.get(s.toUpperCase());
+    }
+  }
+
   // type of the datanode report
   public static enum DatanodeReportType {
     ALL, LIVE, DEAD

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/RollingUpgradeInfo.java

@@ -0,0 +1,65 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.protocol;
+
+import java.util.Date;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
+
+/**
+ * Rolling upgrade information
+ */
+@InterfaceAudience.Private
+@InterfaceStability.Evolving
+public class RollingUpgradeInfo {
+  private long startTime;
+  private long finalizeTime;
+  
+  public RollingUpgradeInfo(long startTime, long finalizeTime) {
+    this.startTime = startTime;
+    this.finalizeTime = finalizeTime;
+  }
+  
+  public boolean isStarted() {
+    return startTime != 0;
+  }
+  
+  /** @return The rolling upgrade starting time. */
+  public long getStartTime() {
+    return startTime;
+  }
+  
+  public boolean isFinalized() {
+    return finalizeTime != 0;
+  }
+
+  public long getFinalizeTime() {
+    return finalizeTime;
+  }
+  
+  @Override
+  public String toString() {
+    return "     Start Time: " + (startTime == 0? "<NOT STARTED>": timestamp2String(startTime))
+      +  "\n  Finalize Time: " + (finalizeTime == 0? "<NOT FINALIZED>": timestamp2String(finalizeTime));
+  }
+  
+  private static String timestamp2String(long timestamp) {
+    return new Date(timestamp) + " (=" + timestamp + ")";
+  }
+}

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocolPB/ClientNamenodeProtocolServerSideTranslatorPB.java

@@ -22,11 +22,12 @@ import java.util.List;
 
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.fs.BatchedRemoteIterator.BatchedEntries;
 import org.apache.hadoop.fs.ContentSummary;
 import org.apache.hadoop.fs.FsServerDefaults;
-import org.apache.hadoop.fs.BatchedRemoteIterator.BatchedEntries;
 import org.apache.hadoop.fs.Options.Rename;
 import org.apache.hadoop.hdfs.protocol.CacheDirectiveEntry;
+import org.apache.hadoop.hdfs.protocol.CacheDirectiveInfo;
 import org.apache.hadoop.hdfs.protocol.CachePoolEntry;
 import org.apache.hadoop.hdfs.protocol.ClientProtocol;
 import org.apache.hadoop.hdfs.protocol.CorruptFileBlocks;
@@ -34,17 +35,17 @@ import org.apache.hadoop.hdfs.protocol.DirectoryListing;
 import org.apache.hadoop.hdfs.protocol.HdfsFileStatus;
 import org.apache.hadoop.hdfs.protocol.LocatedBlock;
 import org.apache.hadoop.hdfs.protocol.LocatedBlocks;
-import org.apache.hadoop.hdfs.protocol.CacheDirectiveInfo;
+import org.apache.hadoop.hdfs.protocol.RollingUpgradeInfo;
 import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport;
 import org.apache.hadoop.hdfs.protocol.SnapshottableDirectoryStatus;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.AbandonBlockRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.AbandonBlockResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.AddBlockRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.AddBlockResponseProto;
-import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.AddCachePoolRequestProto;
-import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.AddCachePoolResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.AddCacheDirectiveRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.AddCacheDirectiveResponseProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.AddCachePoolRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.AddCachePoolResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.AllowSnapshotRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.AllowSnapshotResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.AppendRequestProto;
@@ -100,28 +101,28 @@ import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.GetSna
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.GetSnapshottableDirListingResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.IsFileClosedRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.IsFileClosedResponseProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ListCacheDirectivesRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ListCacheDirectivesResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ListCachePoolsRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ListCachePoolsResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ListCorruptFileBlocksRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ListCorruptFileBlocksResponseProto;
-import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ListCacheDirectivesRequestProto;
-import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ListCacheDirectivesResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.MetaSaveRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.MetaSaveResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.MkdirsRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.MkdirsResponseProto;
-import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ModifyCachePoolRequestProto;
-import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ModifyCachePoolResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ModifyCacheDirectiveRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ModifyCacheDirectiveResponseProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ModifyCachePoolRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ModifyCachePoolResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RecoverLeaseRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RecoverLeaseResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RefreshNodesRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RefreshNodesResponseProto;
-import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RemoveCachePoolRequestProto;
-import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RemoveCachePoolResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RemoveCacheDirectiveRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RemoveCacheDirectiveResponseProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RemoveCachePoolRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RemoveCachePoolResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.Rename2RequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.Rename2ResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RenameRequestProto;
@@ -136,6 +137,8 @@ import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.Restor
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RestoreFailedStorageResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RollEditsRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RollEditsResponseProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RollingUpgradeRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RollingUpgradeResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.SaveNamespaceRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.SaveNamespaceResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.SetBalancerBandwidthRequestProto;
@@ -681,6 +684,20 @@ public class ClientNamenodeProtocolServerSideTranslatorPB implements
     }
   }
 
+  @Override
+  public RollingUpgradeResponseProto rollingUpgrade(RpcController controller,
+      RollingUpgradeRequestProto req) throws ServiceException {
+    try {
+      final RollingUpgradeInfo info = server.rollingUpgrade(
+          PBHelper.convert(req.getAction()));
+      return RollingUpgradeResponseProto.newBuilder()
+          .setRollingUpgradeInfo(PBHelper.convert(info))
+          .build();
+    } catch (IOException e) {
+      throw new ServiceException(e);
+    }
+  }
+
   @Override
   public ListCorruptFileBlocksResponseProto listCorruptFileBlocks(
       RpcController controller, ListCorruptFileBlocksRequestProto req)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocolPB/ClientNamenodeProtocolTranslatorPB.java

@@ -37,8 +37,9 @@ import org.apache.hadoop.fs.UnresolvedLinkException;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.hdfs.protocol.AlreadyBeingCreatedException;
 import org.apache.hadoop.hdfs.protocol.CacheDirectiveEntry;
-import org.apache.hadoop.hdfs.protocol.CachePoolInfo;
+import org.apache.hadoop.hdfs.protocol.CacheDirectiveInfo;
 import org.apache.hadoop.hdfs.protocol.CachePoolEntry;
+import org.apache.hadoop.hdfs.protocol.CachePoolInfo;
 import org.apache.hadoop.hdfs.protocol.ClientProtocol;
 import org.apache.hadoop.hdfs.protocol.CorruptFileBlocks;
 import org.apache.hadoop.hdfs.protocol.DSQuotaExceededException;
@@ -47,18 +48,19 @@ import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
 import org.apache.hadoop.hdfs.protocol.DirectoryListing;
 import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.DatanodeReportType;
+import org.apache.hadoop.hdfs.protocol.HdfsConstants.RollingUpgradeAction;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.SafeModeAction;
 import org.apache.hadoop.hdfs.protocol.HdfsFileStatus;
 import org.apache.hadoop.hdfs.protocol.LocatedBlock;
 import org.apache.hadoop.hdfs.protocol.LocatedBlocks;
 import org.apache.hadoop.hdfs.protocol.NSQuotaExceededException;
-import org.apache.hadoop.hdfs.protocol.CacheDirectiveInfo;
+import org.apache.hadoop.hdfs.protocol.RollingUpgradeInfo;
 import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport;
 import org.apache.hadoop.hdfs.protocol.SnapshottableDirectoryStatus;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.AbandonBlockRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.AddBlockRequestProto;
-import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.AddCachePoolRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.AddCacheDirectiveRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.AddCachePoolRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.AllowSnapshotRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.AppendRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.AppendResponseProto;
@@ -97,19 +99,19 @@ import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.GetSna
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.GetSnapshottableDirListingRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.GetSnapshottableDirListingResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.IsFileClosedRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ListCacheDirectivesRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ListCacheDirectivesResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ListCachePoolsRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ListCachePoolsResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ListCorruptFileBlocksRequestProto;
-import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ListCacheDirectivesRequestProto;
-import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ListCacheDirectivesResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.MetaSaveRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.MkdirsRequestProto;
-import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ModifyCachePoolRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ModifyCacheDirectiveRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ModifyCachePoolRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RecoverLeaseRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RefreshNodesRequestProto;
-import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RemoveCachePoolRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RemoveCacheDirectiveRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RemoveCachePoolRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.Rename2RequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RenameRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RenameSnapshotRequestProto;
@@ -118,6 +120,9 @@ import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.Report
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RestoreFailedStorageRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RollEditsRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RollEditsResponseProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RollingUpgradeInfoProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RollingUpgradeRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RollingUpgradeResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.SaveNamespaceRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.SetBalancerBandwidthRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.SetOwnerRequestProto;
@@ -635,6 +640,19 @@ public class ClientNamenodeProtocolTranslatorPB implements
     }
   }
 
+  @Override
+  public RollingUpgradeInfo rollingUpgrade(RollingUpgradeAction action) throws IOException {
+    final RollingUpgradeRequestProto r = RollingUpgradeRequestProto.newBuilder()
+        .setAction(PBHelper.convert(action)).build();
+    try {
+      final RollingUpgradeResponseProto proto = rpcProxy.rollingUpgrade(null, r);
+      final RollingUpgradeInfoProto info = proto.getRollingUpgradeInfo();
+      return new RollingUpgradeInfo(info.getStartTime(), info.getFinalizeTime());
+    } catch (ServiceException e) {
+      throw ProtobufHelper.getRemoteException(e);
+    }
+  }
+
   @Override
   public CorruptFileBlocks listCorruptFileBlocks(String path, String cookie)
       throws IOException {

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocolPB/PBHelper.java

@@ -39,6 +39,7 @@ import org.apache.hadoop.hdfs.DFSUtil;
 import org.apache.hadoop.hdfs.StorageType;
 import org.apache.hadoop.hdfs.protocol.Block;
 import org.apache.hadoop.hdfs.protocol.CacheDirectiveEntry;
+import org.apache.hadoop.hdfs.protocol.CacheDirectiveInfo;
 import org.apache.hadoop.hdfs.protocol.CacheDirectiveStats;
 import org.apache.hadoop.hdfs.protocol.CachePoolEntry;
 import org.apache.hadoop.hdfs.protocol.CachePoolInfo;
@@ -47,23 +48,25 @@ import org.apache.hadoop.hdfs.protocol.ClientProtocol;
 import org.apache.hadoop.hdfs.protocol.CorruptFileBlocks;
 import org.apache.hadoop.hdfs.protocol.DatanodeID;
 import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
-import org.apache.hadoop.hdfs.protocol.CacheDirectiveInfo;
-import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport;
 import org.apache.hadoop.hdfs.protocol.DatanodeInfo.AdminStates;
 import org.apache.hadoop.hdfs.protocol.DirectoryListing;
 import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.DatanodeReportType;
+import org.apache.hadoop.hdfs.protocol.HdfsConstants.RollingUpgradeAction;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.SafeModeAction;
 import org.apache.hadoop.hdfs.protocol.HdfsFileStatus;
 import org.apache.hadoop.hdfs.protocol.HdfsLocatedFileStatus;
 import org.apache.hadoop.hdfs.protocol.LocatedBlock;
 import org.apache.hadoop.hdfs.protocol.LocatedBlocks;
+import org.apache.hadoop.hdfs.protocol.RollingUpgradeInfo;
+import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport;
 import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport.DiffReportEntry;
 import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport.DiffType;
 import org.apache.hadoop.hdfs.protocol.SnapshottableDirectoryStatus;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.CacheDirectiveEntryProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.CacheDirectiveInfoExpirationProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.CacheDirectiveInfoProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.CacheDirectiveStatsProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.CacheFlagProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.CachePoolEntryProto;
@@ -72,8 +75,9 @@ import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.CacheP
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.CreateFlagProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.DatanodeReportTypeProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.GetFsStatsResponseProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RollingUpgradeActionProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RollingUpgradeInfoProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.SafeModeActionProto;
-import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.CacheDirectiveInfoProto;
 import org.apache.hadoop.hdfs.protocol.proto.DatanodeProtocolProtos.BalancerBandwidthCommandProto;
 import org.apache.hadoop.hdfs.protocol.proto.DatanodeProtocolProtos.BlockCommandProto;
 import org.apache.hadoop.hdfs.protocol.proto.DatanodeProtocolProtos.BlockIdCommandProto;
@@ -1421,6 +1425,39 @@ public class PBHelper {
     }
   }
   
+  public static RollingUpgradeActionProto convert(RollingUpgradeAction a) {
+    switch (a) {
+    case QUERY:
+      return RollingUpgradeActionProto.QUERY;
+    case START:
+      return RollingUpgradeActionProto.START;
+    case FINALIZE:
+      return RollingUpgradeActionProto.FINALIZE;
+    default:
+      throw new IllegalArgumentException("Unexpected value: " + a);
+    }
+  }
+  
+  public static RollingUpgradeAction convert(RollingUpgradeActionProto a) {
+    switch (a) {
+    case QUERY:
+      return RollingUpgradeAction.QUERY;
+    case START:
+      return RollingUpgradeAction.START;
+    case FINALIZE:
+      return RollingUpgradeAction.FINALIZE;
+    default:
+      throw new IllegalArgumentException("Unexpected value: " + a);
+    }
+  }
+
+  public static RollingUpgradeInfoProto convert(RollingUpgradeInfo info) {
+    return RollingUpgradeInfoProto.newBuilder()
+        .setStartTime(info.getStartTime())
+        .setFinalizeTime(info.getFinalizeTime())
+        .build();
+  }
+
   public static CorruptFileBlocks convert(CorruptFileBlocksProto c) {
     if (c == null)
       return null;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java

@@ -168,6 +168,7 @@ import org.apache.hadoop.hdfs.protocol.LocatedBlock;
 import org.apache.hadoop.hdfs.protocol.LocatedBlocks;
 import org.apache.hadoop.hdfs.protocol.QuotaExceededException;
 import org.apache.hadoop.hdfs.protocol.RecoveryInProgressException;
+import org.apache.hadoop.hdfs.protocol.RollingUpgradeInfo;
 import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport;
 import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport.DiffReportEntry;
 import org.apache.hadoop.hdfs.protocol.SnapshottableDirectoryStatus;
@@ -7053,13 +7054,15 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
     }
   }
 
-  void addUpgradeMarker() throws IOException {
+  RollingUpgradeInfo addUpgradeMarker() throws IOException {
+    final long startTime;
     checkSuperuserPrivilege();
     checkOperation(OperationCategory.WRITE);
     writeLock();
     try {
       checkOperation(OperationCategory.WRITE);
 
+      startTime = now();
       getEditLog().logUpgradeMarker();
     } finally {
       writeUnlock();
@@ -7069,6 +7072,7 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
     if (auditLog.isInfoEnabled() && isExternalInvocation()) {
       logAuditEvent(true, "upgrade", null, null, null);
     }
+    return new RollingUpgradeInfo(startTime, 0L);
   }
 
   long addCacheDirective(CacheDirectiveInfo directive, EnumSet<CacheFlag> flags)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NameNodeRpcServer.java

@@ -37,6 +37,7 @@ import java.util.Set;
 import org.apache.commons.logging.Log;
 import org.apache.hadoop.HadoopIllegalArgumentException;
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.BatchedRemoteIterator.BatchedEntries;
 import org.apache.hadoop.fs.CacheFlag;
 import org.apache.hadoop.fs.CommonConfigurationKeys;
 import org.apache.hadoop.fs.ContentSummary;
@@ -48,7 +49,6 @@ import org.apache.hadoop.fs.Options;
 import org.apache.hadoop.fs.ParentNotDirectoryException;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.fs.UnresolvedLinkException;
-import org.apache.hadoop.fs.BatchedRemoteIterator.BatchedEntries;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.fs.permission.PermissionStatus;
 import org.apache.hadoop.ha.HAServiceStatus;
@@ -64,8 +64,8 @@ import org.apache.hadoop.hdfs.protocol.AlreadyBeingCreatedException;
 import org.apache.hadoop.hdfs.protocol.BlockListAsLongs;
 import org.apache.hadoop.hdfs.protocol.CacheDirectiveEntry;
 import org.apache.hadoop.hdfs.protocol.CacheDirectiveInfo;
-import org.apache.hadoop.hdfs.protocol.CachePoolInfo;
 import org.apache.hadoop.hdfs.protocol.CachePoolEntry;
+import org.apache.hadoop.hdfs.protocol.CachePoolInfo;
 import org.apache.hadoop.hdfs.protocol.CorruptFileBlocks;
 import org.apache.hadoop.hdfs.protocol.DSQuotaExceededException;
 import org.apache.hadoop.hdfs.protocol.DatanodeID;
@@ -74,6 +74,7 @@ import org.apache.hadoop.hdfs.protocol.DirectoryListing;
 import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.DatanodeReportType;
+import org.apache.hadoop.hdfs.protocol.HdfsConstants.RollingUpgradeAction;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.SafeModeAction;
 import org.apache.hadoop.hdfs.protocol.HdfsFileStatus;
 import org.apache.hadoop.hdfs.protocol.LocatedBlock;
@@ -81,6 +82,7 @@ import org.apache.hadoop.hdfs.protocol.LocatedBlocks;
 import org.apache.hadoop.hdfs.protocol.NSQuotaExceededException;
 import org.apache.hadoop.hdfs.protocol.QuotaExceededException;
 import org.apache.hadoop.hdfs.protocol.RecoveryInProgressException;
+import org.apache.hadoop.hdfs.protocol.RollingUpgradeInfo;
 import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport;
 import org.apache.hadoop.hdfs.protocol.SnapshottableDirectoryStatus;
 import org.apache.hadoop.hdfs.protocol.UnregisteredNodeException;
@@ -858,6 +860,18 @@ class NameNodeRpcServer implements NamenodeProtocols {
     namesystem.finalizeUpgrade();
   }
 
+  @Override // ClientProtocol
+  public RollingUpgradeInfo rollingUpgrade(RollingUpgradeAction action) throws IOException {
+    LOG.info("rollingUpgrade " + action);
+    switch(action) {
+    case START:
+      return namesystem.addUpgradeMarker();
+    default:
+      // TODO: support other actions.
+      throw new UnsupportedActionException(action + " is not yet supported.");
+    }
+  }
+
   @Override // ClientProtocol
   public void metaSave(String filename) throws IOException {
     namesystem.metaSave(filename);

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

@@ -49,7 +49,9 @@ import org.apache.hadoop.hdfs.protocol.ClientDatanodeProtocol;
 import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.DatanodeReportType;
+import org.apache.hadoop.hdfs.protocol.HdfsConstants.RollingUpgradeAction;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.SafeModeAction;
+import org.apache.hadoop.hdfs.protocol.RollingUpgradeInfo;
 import org.apache.hadoop.hdfs.protocol.SnapshotException;
 import org.apache.hadoop.hdfs.server.namenode.NameNode;
 import org.apache.hadoop.hdfs.server.namenode.TransferFsImage;
@@ -63,6 +65,8 @@ import org.apache.hadoop.security.authorize.RefreshAuthorizationPolicyProtocol;
 import org.apache.hadoop.util.StringUtils;
 import org.apache.hadoop.util.ToolRunner;
 
+import com.google.common.base.Preconditions;
+
 /**
  * This class provides some DFS administrative access shell commands.
  */
@@ -270,7 +274,59 @@ public class DFSAdmin extends FsShell {
       dfs.setQuota(path, HdfsConstants.QUOTA_DONT_SET, quota);
     }
   }
-  
+
+  private static class RollingUpgradeCommand {
+    static final String NAME = "rollingUpgrade";
+    static final String USAGE = "-"+NAME+" [<query|start|finalize>]";
+    static final String DESCRIPTION = USAGE + ":\n"
+        + "     query: query current rolling upgrade status.\n"
+        + "     start: start rolling upgrade."
+        + "  finalize: finalize rolling upgrade.";
+
+    /** Check if a command is the rollingUpgrade command
+     * 
+     * @param cmd A string representation of a command starting with "-"
+     * @return true if this is a clrQuota command; false otherwise
+     */
+    static boolean matches(String cmd) {
+      return ("-"+NAME).equals(cmd); 
+    }
+
+    static int run(DistributedFileSystem dfs, String[] argv, int idx) throws IOException {
+      final RollingUpgradeAction action = RollingUpgradeAction.fromString(
+          argv.length >= 2? argv[1]: "");
+      if (action == null) {
+        throw new IllegalArgumentException("Failed to covert \"" + argv[1]
+            +"\" to " + RollingUpgradeAction.class.getSimpleName());
+      }
+
+      System.out.println(action + " rolling upgrade ...");
+
+      final RollingUpgradeInfo info = dfs.rollingUpgrade(action);
+      switch(action){
+      case QUERY:
+        if (info.isStarted()) {
+          System.out.println("Rolling upgrade is in progress:");
+          System.out.println(info);
+        } else {
+          System.out.println("There is no rolling upgrade in progress.");
+        }
+        break;
+      case START:
+        Preconditions.checkState(info.isStarted());
+        System.out.println("Rolling upgrade is started:");
+        System.out.println(info);
+        break;
+      case FINALIZE:
+        Preconditions.checkState(info.isFinalized());
+        System.out.println("Rolling upgrade is finalized:");
+        System.out.println(info);
+        break;
+      }
+      return 0;
+    }
+  }
+
   /**
    * Construct a DFSAdmin object.
    */
@@ -575,9 +631,11 @@ public class DFSAdmin extends FsShell {
       "\t[" + ClearQuotaCommand.USAGE +"]\n" +
       "\t[" + SetSpaceQuotaCommand.USAGE + "]\n" +
       "\t[" + ClearSpaceQuotaCommand.USAGE +"]\n" +
+      "\t[-finalizeUpgrade]\n" +
+      "\t[" + RollingUpgradeCommand.USAGE +"]\n" +
       "\t[-refreshServiceAcl]\n" +
       "\t[-refreshUserToGroupsMappings]\n" +
-      "\t[refreshSuperUserGroupsConfiguration]\n" +
+      "\t[-refreshSuperUserGroupsConfiguration]\n" +
       "\t[-printTopology]\n" +
       "\t[-refreshNamenodes datanodehost:port]\n"+
       "\t[-deleteBlockPool datanodehost:port blockpoolId [force]]\n"+
@@ -699,6 +757,8 @@ public class DFSAdmin extends FsShell {
       System.out.println(refreshNodes);
     } else if ("finalizeUpgrade".equals(cmd)) {
       System.out.println(finalizeUpgrade);
+    } else if (RollingUpgradeCommand.matches("-"+cmd)) {
+      System.out.println(RollingUpgradeCommand.DESCRIPTION);
     } else if ("metasave".equals(cmd)) {
       System.out.println(metaSave);
     } else if (SetQuotaCommand.matches("-"+cmd)) {
@@ -740,6 +800,7 @@ public class DFSAdmin extends FsShell {
       System.out.println(restoreFailedStorage);
       System.out.println(refreshNodes);
       System.out.println(finalizeUpgrade);
+      System.out.println(RollingUpgradeCommand.DESCRIPTION);
       System.out.println(metaSave);
       System.out.println(SetQuotaCommand.DESCRIPTION);
       System.out.println(ClearQuotaCommand.DESCRIPTION);
@@ -952,6 +1013,9 @@ public class DFSAdmin extends FsShell {
     } else if ("-finalizeUpgrade".equals(cmd)) {
       System.err.println("Usage: java DFSAdmin"
                          + " [-finalizeUpgrade]");
+    } else if (RollingUpgradeCommand.matches(cmd)) {
+      System.err.println("Usage: java DFSAdmin"
+          + " [" + RollingUpgradeCommand.USAGE+"]");
     } else if ("-metasave".equals(cmd)) {
       System.err.println("Usage: java DFSAdmin"
           + " [-metasave filename]");
@@ -1003,6 +1067,7 @@ public class DFSAdmin extends FsShell {
       System.err.println("           [-restoreFailedStorage true|false|check]");
       System.err.println("           [-refreshNodes]");
       System.err.println("           [-finalizeUpgrade]");
+      System.err.println("           ["+RollingUpgradeCommand.USAGE+"]");
       System.err.println("           [-metasave filename]");
       System.err.println("           [-refreshServiceAcl]");
       System.err.println("           [-refreshUserToGroupsMappings]");
@@ -1087,6 +1152,11 @@ public class DFSAdmin extends FsShell {
         printUsage(cmd);
         return exitCode;
       }
+    } else if (RollingUpgradeCommand.matches(cmd)) {
+      if (argv.length < 1 || argv.length > 2) {
+        printUsage(cmd);
+        return exitCode;
+      }
     } else if ("-metasave".equals(cmd)) {
       if (argv.length != 2) {
         printUsage(cmd);
@@ -1162,6 +1232,8 @@ public class DFSAdmin extends FsShell {
         exitCode = refreshNodes();
       } else if ("-finalizeUpgrade".equals(cmd)) {
         exitCode = finalizeUpgrade();
+      } else if (RollingUpgradeCommand.matches(cmd)) {
+        exitCode = RollingUpgradeCommand.run(getDFS(), argv, i);
       } else if ("-metasave".equals(cmd)) {
         exitCode = metaSave(argv, i);
       } else if (ClearQuotaCommand.matches(cmd)) {

hadoop-hdfs-project/hadoop-hdfs/src/main/proto/ClientNamenodeProtocol.proto

@@ -332,6 +332,25 @@ message FinalizeUpgradeRequestProto { // no parameters
 message FinalizeUpgradeResponseProto { // void response
 }
 
+enum RollingUpgradeActionProto {
+  QUERY = 1;
+  START = 2;
+  FINALIZE = 3;
+}
+
+message RollingUpgradeRequestProto {
+  required RollingUpgradeActionProto action = 1;
+}
+
+message RollingUpgradeInfoProto {
+  required uint64 startTime = 1;
+  required uint64 finalizeTime = 2;
+}
+
+message RollingUpgradeResponseProto {
+  required RollingUpgradeInfoProto rollingUpgradeInfo= 1;
+}
+
 message ListCorruptFileBlocksRequestProto {
   required string path = 1;
   optional string cookie = 2;
@@ -658,6 +677,8 @@ service ClientNamenodeProtocol {
   rpc refreshNodes(RefreshNodesRequestProto) returns(RefreshNodesResponseProto);
   rpc finalizeUpgrade(FinalizeUpgradeRequestProto)
       returns(FinalizeUpgradeResponseProto);
+  rpc rollingUpgrade(RollingUpgradeRequestProto)
+      returns(RollingUpgradeResponseProto);
   rpc listCorruptFileBlocks(ListCorruptFileBlocksRequestProto)
       returns(ListCorruptFileBlocksResponseProto);
   rpc metaSave(MetaSaveRequestProto) returns(MetaSaveResponseProto);

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

@@ -0,0 +1,73 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.hdfs.tools.DFSAdmin;
+import org.junit.Assert;
+import org.junit.Test;
+
+
+/**
+ * This class tests rolling upgrade.
+ */
+public class TestRollingUpgrade {
+  /**
+   * Test DFSAdmin Upgrade Command.
+   */
+  @Test
+  public void testDFSAdminRollingUpgradeCommand() throws Exception {
+    // start a cluster 
+    final Configuration conf = new HdfsConfiguration();
+    MiniDFSCluster cluster = null;
+    try {
+      cluster = new MiniDFSCluster.Builder(conf).numDataNodes(0).build();
+      cluster.waitActive();
+
+      final Path foo = new Path("/foo");
+      final Path bar = new Path("/bar");
+
+      {
+        final DistributedFileSystem dfs = cluster.getFileSystem();
+        final DFSAdmin dfsadmin = new DFSAdmin(conf);
+        dfs.mkdirs(foo);
+
+        {
+          //start rolling upgrade
+          final String[] args = {"-rollingUpgrade", "start"};
+          dfsadmin.run(args);
+        }
+
+        dfs.mkdirs(bar);
+        
+        Assert.assertTrue(dfs.exists(foo));
+        Assert.assertTrue(dfs.exists(bar));
+      }
+      
+      cluster.restartNameNode();
+      {
+        final DistributedFileSystem dfs = cluster.getFileSystem();
+        Assert.assertTrue(dfs.exists(foo));
+        Assert.assertFalse(dfs.exists(bar));
+      }
+    } finally {
+      if(cluster != null) cluster.shutdown();
+    }
+  }
+}