HDFS-7349. Support DFS command for the EC encoding (Contributed by Vinayakumar B)

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FsShell.java

@@ -111,6 +111,10 @@ public class FsShell extends Configured implements Tool {
     return getTrash().getCurrentTrashDir();
   }
 
+  protected String getUsagePrefix() {
+    return usagePrefix;
+  }
+
   // NOTE: Usage/Help are inner classes to allow access to outer methods
   // that access commandFactory
   
@@ -194,7 +198,7 @@ public class FsShell extends Configured implements Tool {
       }
     } else {
       // display help or usage for all commands 
-      out.println(usagePrefix);
+      out.println(getUsagePrefix());
       
       // display list of short usages
       ArrayList<Command> instances = new ArrayList<Command>();
@@ -218,7 +222,7 @@ public class FsShell extends Configured implements Tool {
   }
 
   private void printInstanceUsage(PrintStream out, Command instance) {
-    out.println(usagePrefix + " " + instance.getUsage());
+    out.println(getUsagePrefix() + " " + instance.getUsage());
   }
 
   private void printInstanceHelp(PrintStream out, Command instance) {

hadoop-hdfs-project/hadoop-hdfs/CHANGES-HDFS-EC-7285.txt

@@ -79,4 +79,6 @@
     operation fails. (Rakesh R via Zhe Zhang)
 
     HDFS-8123. Erasure Coding: Better to move EC related proto messages to a
-    separate erasurecoding proto file (Rakesh R via vinayakumarb)
+    separate erasurecoding proto file (Rakesh R via vinayakumarb)
+
+    HDFS-7349. Support DFS command for the EC encoding (vinayakumarb)

hadoop-hdfs-project/hadoop-hdfs/src/main/bin/hdfs

@@ -134,6 +134,11 @@ case ${COMMAND} in
     hadoop_debug "Appending HADOOP_CLIENT_OPTS onto HADOOP_OPTS"
     HADOOP_OPTS="${HADOOP_OPTS} ${HADOOP_CLIENT_OPTS}"
   ;;
+  erasurecode)
+    CLASS=org.apache.hadoop.hdfs.tools.erasurecode.ECCli
+    hadoop_debug "Appending HADOOP_CLIENT_OPTS onto HADOOP_OPTS"
+    HADOOP_OPTS="${HADOOP_OPTS} ${HADOOP_CLIENT_OPTS}"
+  ;;
   fetchdt)
     CLASS=org.apache.hadoop.hdfs.tools.DelegationTokenFetcher
   ;;

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

@@ -120,6 +120,7 @@ import org.apache.hadoop.hdfs.protocol.DatanodeID;
 import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
 import org.apache.hadoop.hdfs.protocol.DirectoryListing;
 import org.apache.hadoop.hdfs.protocol.ECInfo;
+import org.apache.hadoop.hdfs.protocol.ECZoneInfo;
 import org.apache.hadoop.hdfs.protocol.EncryptionZone;
 import org.apache.hadoop.hdfs.protocol.EncryptionZoneIterator;
 import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
@@ -3351,4 +3352,21 @@ public class DFSClient implements java.io.Closeable, RemotePeerFactory,
     }
     return scope;
   }
+
+  /**
+   * Get the erasure coding zone information for the specified path
+   * 
+   * @param src path to get the information for
+   * @return Returns the zone information if path is in EC Zone, null otherwise
+   * @throws IOException
+   */
+  public ECZoneInfo getErasureCodingZoneInfo(String src) throws IOException {
+    checkOpen();
+    try {
+      return namenode.getErasureCodingZoneInfo(src);
+    } catch (RemoteException re) {
+      throw re.unwrapRemoteException(FileNotFoundException.class,
+          AccessControlException.class, UnresolvedPathException.class);
+    }
+  }
 }

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

@@ -75,6 +75,7 @@ import org.apache.hadoop.hdfs.protocol.CachePoolInfo;
 import org.apache.hadoop.hdfs.protocol.ClientProtocol;
 import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
 import org.apache.hadoop.hdfs.protocol.DirectoryListing;
+import org.apache.hadoop.hdfs.protocol.ECZoneInfo;
 import org.apache.hadoop.hdfs.protocol.EncryptionZone;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.DatanodeReportType;
@@ -2306,4 +2307,35 @@ public class DistributedFileSystem extends FileSystem {
       }
     }.resolve(this, absF);
   }
+
+  /**
+   * Get ErasureCoding zone information for the specified path
+   * 
+   * @param path
+   * @return Returns the zone information if path is in EC zone, null otherwise
+   * @throws IOException
+   */
+  public ECZoneInfo getErasureCodingZoneInfo(final Path path)
+      throws IOException {
+    Path absF = fixRelativePart(path);
+    return new FileSystemLinkResolver<ECZoneInfo>() {
+      @Override
+      public ECZoneInfo doCall(final Path p) throws IOException,
+          UnresolvedLinkException {
+        return dfs.getErasureCodingZoneInfo(getPathName(p));
+      }
+
+      @Override
+      public ECZoneInfo next(final FileSystem fs, final Path p)
+          throws IOException {
+        if (fs instanceof DistributedFileSystem) {
+          DistributedFileSystem myDfs = (DistributedFileSystem) fs;
+          return myDfs.getErasureCodingZoneInfo(p);
+        }
+        throw new UnsupportedOperationException(
+            "Cannot getErasureCodingZoneInfo through a symlink to a "
+                + "non-DistributedFileSystem: " + path + " -> " + p);
+      }
+    }.resolve(this, absF);
+  }
 }

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

@@ -1484,4 +1484,13 @@ public interface ClientProtocol {
    */
   @Idempotent
   public ECSchema[] getECSchemas() throws IOException;
+
+  /**
+   * Get the information about the EC zone for the path
+   * 
+   * @param src path to get the info for
+   * @throws IOException
+   */
+  @Idempotent
+  public ECZoneInfo getErasureCodingZoneInfo(String src) throws IOException;
 }

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

@@ -0,0 +1,56 @@
+/**
+ * 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 org.apache.hadoop.io.erasurecode.ECSchema;
+
+/**
+ * Information about the EC Zone at the specified path.
+ */
+public class ECZoneInfo {
+
+  private String dir;
+  private ECSchema schema;
+
+  public ECZoneInfo(String dir, ECSchema schema) {
+    this.dir = dir;
+    this.schema = schema;
+  }
+
+  /**
+   * Get directory of the EC zone.
+   * 
+   * @return
+   */
+  public String getDir() {
+    return dir;
+  }
+
+  /**
+   * Get the schema for the EC Zone
+   * 
+   * @return
+   */
+  public ECSchema getSchema() {
+    return schema;
+  }
+
+  @Override
+  public String toString() {
+    return "Dir: " + getDir() + ", Schema: " + schema;
+  }
+}

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

@@ -36,6 +36,7 @@ import org.apache.hadoop.hdfs.protocol.ClientProtocol;
 import org.apache.hadoop.hdfs.protocol.CorruptFileBlocks;
 import org.apache.hadoop.hdfs.protocol.DirectoryListing;
 import org.apache.hadoop.hdfs.protocol.ECInfo;
+import org.apache.hadoop.hdfs.protocol.ECZoneInfo;
 import org.apache.hadoop.hdfs.protocol.EncryptionZone;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.protocol.HdfsFileStatus;
@@ -201,6 +202,8 @@ import org.apache.hadoop.hdfs.protocol.proto.EncryptionZonesProtos.ListEncryptio
 import org.apache.hadoop.hdfs.protocol.proto.EncryptionZonesProtos.ListEncryptionZonesRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ErasureCodingProtos.GetECSchemasRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ErasureCodingProtos.GetECSchemasResponseProto;
+import org.apache.hadoop.hdfs.protocol.proto.ErasureCodingProtos.GetECZoneInfoRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ErasureCodingProtos.GetECZoneInfoResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ErasureCodingProtos.GetErasureCodingInfoRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ErasureCodingProtos.GetErasureCodingInfoResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ErasureCodingProtos.CreateErasureCodingZoneRequestProto;
@@ -1551,4 +1554,19 @@ public class ClientNamenodeProtocolServerSideTranslatorPB implements
       throw new ServiceException(e);
     }
   }
+
+  @Override
+  public GetECZoneInfoResponseProto getErasureCodingZoneInfo(RpcController controller,
+      GetECZoneInfoRequestProto request) throws ServiceException {
+    try {
+      ECZoneInfo ecZoneInfo = server.getErasureCodingZoneInfo(request.getSrc());
+      GetECZoneInfoResponseProto.Builder builder = GetECZoneInfoResponseProto.newBuilder();
+      if (ecZoneInfo != null) {
+        builder.setECZoneInfo(PBHelper.convertECZoneInfo(ecZoneInfo));
+      }
+      return builder.build();
+    } catch (IOException e) {
+      throw new ServiceException(e);
+    }
+  }
 }

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

@@ -59,6 +59,7 @@ import org.apache.hadoop.hdfs.protocol.DatanodeID;
 import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
 import org.apache.hadoop.hdfs.protocol.DirectoryListing;
 import org.apache.hadoop.hdfs.protocol.ECInfo;
+import org.apache.hadoop.hdfs.protocol.ECZoneInfo;
 import org.apache.hadoop.hdfs.protocol.EncryptionZone;
 import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.DatanodeReportType;
@@ -167,6 +168,8 @@ import org.apache.hadoop.hdfs.protocol.proto.EncryptionZonesProtos.GetEZForPathR
 import org.apache.hadoop.hdfs.protocol.proto.EncryptionZonesProtos.ListEncryptionZonesRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ErasureCodingProtos.GetECSchemasRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ErasureCodingProtos.GetECSchemasResponseProto;
+import org.apache.hadoop.hdfs.protocol.proto.ErasureCodingProtos.GetECZoneInfoRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ErasureCodingProtos.GetECZoneInfoResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ErasureCodingProtos.GetErasureCodingInfoRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ErasureCodingProtos.GetErasureCodingInfoResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ErasureCodingProtos.CreateErasureCodingZoneRequestProto;
@@ -1576,4 +1579,20 @@ public class ClientNamenodeProtocolTranslatorPB implements
       throw ProtobufHelper.getRemoteException(e);
     }
   }
+
+  @Override
+  public ECZoneInfo getErasureCodingZoneInfo(String src) throws IOException {
+    GetECZoneInfoRequestProto req = GetECZoneInfoRequestProto.newBuilder()
+        .setSrc(src).build();
+    try {
+      GetECZoneInfoResponseProto response = rpcProxy.getErasureCodingZoneInfo(
+          null, req);
+      if (response.hasECZoneInfo()) {
+        return PBHelper.convertECZoneInfo(response.getECZoneInfo());
+      }
+      return null;
+    } catch (ServiceException e) {
+      throw ProtobufHelper.getRemoteException(e);
+    }
+  }
 }

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

@@ -76,6 +76,7 @@ import org.apache.hadoop.hdfs.protocol.DirectoryListing;
 import org.apache.hadoop.hdfs.protocol.EncryptionZone;
 import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
 import org.apache.hadoop.fs.FileEncryptionInfo;
+import org.apache.hadoop.hdfs.protocol.ECZoneInfo;
 import org.apache.hadoop.hdfs.protocol.FsPermissionExtension;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.DatanodeReportType;
@@ -134,6 +135,7 @@ import org.apache.hadoop.hdfs.protocol.proto.DatanodeProtocolProtos.BlockReportC
 import org.apache.hadoop.hdfs.protocol.proto.ErasureCodingProtos.ECInfoProto;
 import org.apache.hadoop.hdfs.protocol.proto.ErasureCodingProtos.ECSchemaOptionEntryProto;
 import org.apache.hadoop.hdfs.protocol.proto.ErasureCodingProtos.ECSchemaProto;
+import org.apache.hadoop.hdfs.protocol.proto.ErasureCodingProtos.ECZoneInfoProto;
 import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos;
 import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.BlockKeyProto;
 import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.BlockProto;
@@ -3138,4 +3140,14 @@ public class PBHelper {
     }
     return builder.build();
   }
+
+  public static ECZoneInfoProto convertECZoneInfo(ECZoneInfo ecZoneInfo) {
+    return ECZoneInfoProto.newBuilder().setDir(ecZoneInfo.getDir())
+        .setSchema(convertECSchema(ecZoneInfo.getSchema())).build();
+  }
+
+  public static ECZoneInfo convertECZoneInfo(ECZoneInfoProto ecZoneInfoProto) {
+    return new ECZoneInfo(ecZoneInfoProto.getDir(),
+        convertECSchema(ecZoneInfoProto.getSchema()));
+  }
 }

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

@@ -22,6 +22,7 @@ import com.google.common.collect.Lists;
 import org.apache.hadoop.fs.XAttr;
 import org.apache.hadoop.fs.XAttrSetFlag;
 import org.apache.hadoop.hdfs.XAttrHelper;
+import org.apache.hadoop.hdfs.protocol.ECZoneInfo;
 import org.apache.hadoop.hdfs.protocol.proto.ErasureCodingProtos.ECSchemaProto;
 import org.apache.hadoop.hdfs.protocolPB.PBHelper;
 import org.apache.hadoop.io.erasurecode.ECSchema;
@@ -57,7 +58,12 @@ public class ErasureCodingZoneManager {
     return getECSchema(iip) != null;
   }
 
-  ECSchema getECSchema(INodesInPath iip) throws IOException{
+  ECSchema getECSchema(INodesInPath iip) throws IOException {
+    ECZoneInfo ecZoneInfo = getECZoneInfo(iip);
+    return ecZoneInfo == null ? null : ecZoneInfo.getSchema();
+  }
+
+  ECZoneInfo getECZoneInfo(INodesInPath iip) throws IOException {
     assert dir.hasReadLock();
     Preconditions.checkNotNull(iip);
     List<INode> inodes = iip.getReadOnlyINodes();
@@ -80,7 +86,8 @@ public class ErasureCodingZoneManager {
         if (XATTR_ERASURECODING_ZONE.equals(XAttrHelper.getPrefixName(xAttr))) {
           ECSchemaProto ecSchemaProto;
           ecSchemaProto = ECSchemaProto.parseFrom(xAttr.getValue());
-          return PBHelper.convertECSchema(ecSchemaProto);
+          ECSchema schema = PBHelper.convertECSchema(ecSchemaProto);
+          return new ECZoneInfo(inode.getFullPathName(), schema);
         }
       }
     }

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

@@ -42,6 +42,7 @@ import org.apache.hadoop.hdfs.DFSUtil;
 import org.apache.hadoop.hdfs.XAttrHelper;
 import org.apache.hadoop.hdfs.protocol.Block;
 import org.apache.hadoop.hdfs.protocol.BlockStoragePolicy;
+import org.apache.hadoop.hdfs.protocol.ECZoneInfo;
 import org.apache.hadoop.hdfs.protocol.EncryptionZone;
 import org.apache.hadoop.hdfs.protocol.FSLimitException.MaxDirectoryItemsExceededException;
 import org.apache.hadoop.hdfs.protocol.FSLimitException.PathComponentTooLongException;
@@ -1249,6 +1250,15 @@ public class FSDirectory implements Closeable {
     }
   }
 
+  ECZoneInfo getECZoneInfo(INodesInPath iip) throws IOException {
+    readLock();
+    try {
+      return ecZoneManager.getECZoneInfo(iip);
+    } finally {
+      readUnlock();
+    }
+  }
+
   static INode resolveLastINode(INodesInPath iip) throws FileNotFoundException {
     INode inode = iip.getLastINode();
     if (inode == null) {

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

@@ -181,6 +181,7 @@ import org.apache.hadoop.hdfs.protocol.DatanodeID;
 import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
 import org.apache.hadoop.hdfs.protocol.DirectoryListing;
 import org.apache.hadoop.hdfs.protocol.ECInfo;
+import org.apache.hadoop.hdfs.protocol.ECZoneInfo;
 import org.apache.hadoop.hdfs.protocol.EncryptionZone;
 import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants;
@@ -7593,6 +7594,29 @@ public class FSNamesystem implements Namesystem, FSNamesystemMBean,
     return null;
   }
 
+  /**
+   * Get the erasure coding zone information for specified path
+   */
+  ECZoneInfo getErasureCodingZoneInfo(String src) throws AccessControlException,
+      UnresolvedLinkException, IOException {
+    checkOperation(OperationCategory.READ);
+    final byte[][] pathComponents = FSDirectory
+        .getPathComponentsForReservedPath(src);
+    final FSPermissionChecker pc = getPermissionChecker();
+    readLock();
+    try {
+      checkOperation(OperationCategory.READ);
+      src = dir.resolvePath(pc, src, pathComponents);
+      final INodesInPath iip = dir.getINodesInPath(src, true);
+      if (isPermissionEnabled) {
+        dir.checkPathAccess(pc, iip, FsAction.READ);
+      }
+      return dir.getECZoneInfo(iip);
+    } finally {
+      readUnlock();
+    }
+  }
+
   /**
    * Get available ECSchemas
    */

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

@@ -85,6 +85,7 @@ import org.apache.hadoop.hdfs.protocol.DatanodeID;
 import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
 import org.apache.hadoop.hdfs.protocol.DirectoryListing;
 import org.apache.hadoop.hdfs.protocol.ECInfo;
+import org.apache.hadoop.hdfs.protocol.ECZoneInfo;
 import org.apache.hadoop.hdfs.protocol.EncryptionZone;
 import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
 import org.apache.hadoop.hdfs.protocol.FSLimitException;
@@ -2043,4 +2044,10 @@ class NameNodeRpcServer implements NamenodeProtocols {
     checkNNStartup();
     return namesystem.getECSchemas();
   }
+
+  @Override // ClientProtocol
+  public ECZoneInfo getErasureCodingZoneInfo(String src) throws IOException {
+    checkNNStartup();
+    return namesystem.getErasureCodingZoneInfo(src);
+  }
 }

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

@@ -0,0 +1,48 @@
+/**
+ * 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.tools.erasurecode;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FsShell;
+import org.apache.hadoop.fs.shell.CommandFactory;
+import org.apache.hadoop.hdfs.HdfsConfiguration;
+import org.apache.hadoop.util.ToolRunner;
+
+/**
+ * CLI for the erasure code encoding operations.
+ */
+public class ECCli extends FsShell {
+
+  private final static String usagePrefix =
+      "Usage: hdfs erasurecode [generic options]";
+
+  @Override
+  protected String getUsagePrefix() {
+    return usagePrefix;
+  }
+
+  @Override
+  protected void registerCommands(CommandFactory factory) {
+    factory.registerCommands(ECCommand.class);
+  }
+
+  public static void main(String[] args) throws Exception {
+    Configuration conf = new HdfsConfiguration();
+    int res = ToolRunner.run(conf, new ECCli(), args);
+    System.exit(res);
+  }
+}

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

@@ -0,0 +1,209 @@
+/**
+ * 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.tools.erasurecode;
+
+import java.io.IOException;
+import java.util.LinkedList;
+
+import org.apache.hadoop.HadoopIllegalArgumentException;
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.fs.shell.Command;
+import org.apache.hadoop.fs.shell.CommandFactory;
+import org.apache.hadoop.fs.shell.PathData;
+import org.apache.hadoop.hdfs.DistributedFileSystem;
+import org.apache.hadoop.hdfs.protocol.ECZoneInfo;
+import org.apache.hadoop.hdfs.server.namenode.UnsupportedActionException;
+import org.apache.hadoop.io.erasurecode.ECSchema;
+import org.apache.hadoop.util.StringUtils;
+
+/**
+ * Erasure Coding CLI commands
+ */
+@InterfaceAudience.Private
+@InterfaceStability.Evolving
+public abstract class ECCommand extends Command {
+
+  public static void registerCommands(CommandFactory factory) {
+    // Register all commands of Erasure CLI, with a '-' at the beginning in name
+    // of the command.
+    factory.addClass(CreateECZoneCommand.class, "-" + CreateECZoneCommand.NAME);
+    factory.addClass(GetECZoneInfoCommand.class, "-"
+        + GetECZoneInfoCommand.NAME);
+    factory.addClass(ListECSchemas.class, "-" + ListECSchemas.NAME);
+  }
+
+  @Override
+  public String getCommandName() {
+    return getName();
+  }
+
+  @Override
+  protected void run(Path path) throws IOException {
+    throw new RuntimeException("Not suppose to get here");
+  }
+
+  @Deprecated
+  @Override
+  public int runAll() {
+    return run(args);
+  }
+
+  @Override
+  protected void processPath(PathData item) throws IOException {
+    if (!(item.fs instanceof DistributedFileSystem)) {
+      throw new UnsupportedActionException(
+          "Erasure commands are only supported for the HDFS paths");
+    }
+  }
+
+  /**
+   * Create EC encoding zone command. Zones are created to use specific EC
+   * encoding schema, other than default while encoding the files under some
+   * specific directory.
+   */
+  static class CreateECZoneCommand extends ECCommand {
+    public static final String NAME = "createZone";
+    public static final String USAGE = "[-s <schemaName>] <path>";
+    public static final String DESCRIPTION = 
+        "Create a zone to encode files using a specified schema\n"
+        + "Options :\n"
+        + "  -s <schemaName> : EC schema name to encode files. "
+        + "If not passed default schema will be used\n"
+        + "  <path>  : Path to an empty directory. Under this directory "
+        + "files will be encoded using specified schema";
+    private String schemaName;
+    private ECSchema schema = null;
+
+    @Override
+    protected void processOptions(LinkedList<String> args) throws IOException {
+      schemaName = StringUtils.popOptionWithArgument("-s", args);
+      if (args.isEmpty()) {
+        throw new HadoopIllegalArgumentException("<path> is missing");
+      }
+      if (args.size() > 1) {
+        throw new HadoopIllegalArgumentException("Too many arguments");
+      }
+    }
+
+    @Override
+    protected void processPath(PathData item) throws IOException {
+      super.processPath(item);
+      DistributedFileSystem dfs = (DistributedFileSystem) item.fs;
+      try {
+        if (schemaName != null) {
+          ECSchema[] ecSchemas = dfs.getClient().getECSchemas();
+          for (ECSchema ecSchema : ecSchemas) {
+            if (schemaName.equals(ecSchema.getSchemaName())) {
+              schema = ecSchema;
+              break;
+            }
+          }
+          if (schema == null) {
+            StringBuilder sb = new StringBuilder();
+            sb.append("Schema '");
+            sb.append(schemaName);
+            sb.append("' does not match any of the supported schemas.");
+            sb.append("Please select any one of [");
+            for (ECSchema ecSchema : ecSchemas) {
+              sb.append(ecSchema.getSchemaName());
+              sb.append(", ");
+            }
+            throw new HadoopIllegalArgumentException(sb.toString());
+          }
+        }
+        dfs.createErasureCodingZone(item.path, schema);
+        out.println("EC Zone created successfully at " + item.path);
+      } catch (IOException e) {
+        throw new IOException("Unable to create EC zone for the path "
+            + item.path, e);
+      }
+    }
+  }
+
+  /**
+   * Get the information about the zone
+   */
+  static class GetECZoneInfoCommand extends ECCommand {
+    public static final String NAME = "getZoneInfo";
+    public static final String USAGE = "<path>";
+    public static final String DESCRIPTION =
+        "Get information about the EC zone at specified path\n";
+
+    @Override
+    protected void processOptions(LinkedList<String> args) throws IOException {
+      if (args.isEmpty()) {
+        throw new HadoopIllegalArgumentException("<path> is missing");
+      }
+      if (args.size() > 1) {
+        throw new HadoopIllegalArgumentException("Too many arguments");
+      }
+    }
+
+    @Override
+    protected void processPath(PathData item) throws IOException {
+      super.processPath(item);
+      DistributedFileSystem dfs = (DistributedFileSystem) item.fs;
+      try {
+        ECZoneInfo ecZoneInfo = dfs.getErasureCodingZoneInfo(item.path);
+        out.println(ecZoneInfo.toString());
+      } catch (IOException e) {
+        throw new IOException("Unable to create EC zone for the path "
+            + item.path, e);
+      }
+    }
+  }
+
+  /**
+   * List all supported EC Schemas
+   */
+  static class ListECSchemas extends ECCommand {
+    public static final String NAME = "listSchemas";
+    public static final String USAGE = "";
+    public static final String DESCRIPTION = 
+        "Get the list of ECSchemas supported\n";
+
+    @Override
+    protected void processOptions(LinkedList<String> args) throws IOException {
+      if (!args.isEmpty()) {
+        throw new HadoopIllegalArgumentException("Too many parameters");
+      }
+
+      FileSystem fs = FileSystem.get(getConf());
+      if (fs instanceof DistributedFileSystem == false) {
+        throw new UnsupportedActionException(
+            "Erasure commands are only supported for the HDFS");
+      }
+      DistributedFileSystem dfs = (DistributedFileSystem) fs;
+
+      ECSchema[] ecSchemas = dfs.getClient().getECSchemas();
+      StringBuilder sb = new StringBuilder();
+      int i = 0;
+      while (i < ecSchemas.length) {
+        ECSchema ecSchema = ecSchemas[i];
+        sb.append(ecSchema.getSchemaName());
+        i++;
+        if (i < ecSchemas.length) {
+          sb.append(", ");
+        }
+      }
+      out.println(sb.toString());
+    }
+  }
+}

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

@@ -867,4 +867,6 @@ service ClientNamenodeProtocol {
       returns(GetErasureCodingInfoResponseProto);
   rpc getECSchemas(GetECSchemasRequestProto)
       returns(GetECSchemasResponseProto);
+  rpc getErasureCodingZoneInfo(GetECZoneInfoRequestProto) 
+      returns(GetECZoneInfoResponseProto);
 }

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

@@ -49,6 +49,13 @@ message ECInfoProto {
  required ECSchemaProto schema = 2;
 }
 
+/**
+ * ECZoneInfo
+ */
+message ECZoneInfoProto {
+  required string dir = 1;
+  required ECSchemaProto schema = 2;
+}
 
 message CreateErasureCodingZoneRequestProto {
   required string src = 1;
@@ -72,3 +79,11 @@ message GetECSchemasRequestProto { // void request
 message GetECSchemasResponseProto {
   repeated ECSchemaProto schemas = 1;
 }
+
+message GetECZoneInfoRequestProto {
+  required string src = 1; // path to get the zone info
+}
+
+message GetECZoneInfoResponseProto {
+  optional ECZoneInfoProto ECZoneInfo = 1;
+}