| /** |
| * 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.server.protocol; |
| |
| import java.io.IOException; |
| |
| import org.apache.hadoop.hdfs.DFSConfigKeys; |
| import org.apache.hadoop.hdfs.protocol.DatanodeInfo; |
| import org.apache.hadoop.hdfs.security.token.block.ExportedBlockKeys; |
| import org.apache.hadoop.hdfs.server.namenode.CheckpointSignature; |
| import org.apache.hadoop.ipc.VersionedProtocol; |
| import org.apache.hadoop.security.KerberosInfo; |
| |
| /***************************************************************************** |
| * Protocol that a secondary NameNode uses to communicate with the NameNode. |
| * It's used to get part of the name node state |
| *****************************************************************************/ |
| @KerberosInfo( |
| serverPrincipal = DFSConfigKeys.DFS_NAMENODE_USER_NAME_KEY, |
| clientPrincipal = DFSConfigKeys.DFS_NAMENODE_USER_NAME_KEY) |
| public interface NamenodeProtocol extends VersionedProtocol { |
| /** |
| * 3: new method added: getAccessKeys() |
| */ |
| public static final long versionID = 3L; |
| |
| /** Get a list of blocks belonged to <code>datanode</code> |
| * whose total size is equal to <code>size</code> |
| * @param datanode a data node |
| * @param size requested size |
| * @return a list of blocks & their locations |
| * @throws RemoteException if size is less than or equal to 0 or |
| datanode does not exist |
| */ |
| public BlocksWithLocations getBlocks(DatanodeInfo datanode, long size) |
| throws IOException; |
| |
| /** |
| * Get the current block keys |
| * |
| * @return ExportedBlockKeys containing current block keys |
| * @throws IOException |
| */ |
| public ExportedBlockKeys getBlockKeys() throws IOException; |
| |
| /** |
| * Get the size of the current edit log (in bytes). |
| * @return The number of bytes in the current edit log. |
| * @throws IOException |
| */ |
| public long getEditLogSize() throws IOException; |
| |
| /** |
| * Closes the current edit log and opens a new one. The |
| * call fails if the file system is in SafeMode. |
| * @throws IOException |
| * @return a unique token to identify this transaction. |
| */ |
| public CheckpointSignature rollEditLog() throws IOException; |
| |
| /** |
| * Rolls the fsImage log. It removes the old fsImage, copies the |
| * new image to fsImage, removes the old edits and renames edits.new |
| * to edits. The call fails if any of the four files are missing. |
| * @throws IOException |
| */ |
| public void rollFsImage() throws IOException; |
| } |