001 /**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements. See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership. The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License. You may obtain a copy of the License at
009 *
010 * http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018 package org.apache.hadoop.hdfs.server.common;
019
020 import java.io.DataInput;
021 import java.io.DataOutput;
022 import java.io.IOException;
023
024 import org.apache.hadoop.classification.InterfaceAudience;
025
026 /************************************
027 * Some handy internal HDFS constants
028 *
029 ************************************/
030
031 @InterfaceAudience.Private
032 public final class HdfsServerConstants {
033 /* Hidden constructor */
034 private HdfsServerConstants() { }
035
036 /**
037 * Type of the node
038 */
039 static public enum NodeType {
040 NAME_NODE,
041 DATA_NODE;
042 }
043
044 /** Startup options */
045 static public enum StartupOption{
046 FORMAT ("-format"),
047 CLUSTERID ("-clusterid"),
048 GENCLUSTERID ("-genclusterid"),
049 REGULAR ("-regular"),
050 BACKUP ("-backup"),
051 CHECKPOINT("-checkpoint"),
052 UPGRADE ("-upgrade"),
053 ROLLBACK("-rollback"),
054 FINALIZE("-finalize"),
055 IMPORT ("-importCheckpoint");
056
057 private String name = null;
058
059 // Used only with format and upgrade options
060 private String clusterId = null;
061
062 private StartupOption(String arg) {this.name = arg;}
063 public String getName() {return name;}
064 public NamenodeRole toNodeRole() {
065 switch(this) {
066 case BACKUP:
067 return NamenodeRole.BACKUP;
068 case CHECKPOINT:
069 return NamenodeRole.CHECKPOINT;
070 default:
071 return NamenodeRole.NAMENODE;
072 }
073 }
074
075 public void setClusterId(String cid) {
076 clusterId = cid;
077 }
078
079 public String getClusterId() {
080 return clusterId;
081 }
082 }
083
084 // Timeouts for communicating with DataNode for streaming writes/reads
085 public static int READ_TIMEOUT = 60 * 1000;
086 public static int READ_TIMEOUT_EXTENSION = 5 * 1000;
087 public static int WRITE_TIMEOUT = 8 * 60 * 1000;
088 public static int WRITE_TIMEOUT_EXTENSION = 5 * 1000; //for write pipeline
089
090 /**
091 * Defines the NameNode role.
092 */
093 static public enum NamenodeRole {
094 NAMENODE ("NameNode"),
095 BACKUP ("Backup Node"),
096 CHECKPOINT("Checkpoint Node");
097
098 private String description = null;
099 private NamenodeRole(String arg) {this.description = arg;}
100
101 public String toString() {
102 return description;
103 }
104 }
105
106 /**
107 * Block replica states, which it can go through while being constructed.
108 */
109 static public enum ReplicaState {
110 /** Replica is finalized. The state when replica is not modified. */
111 FINALIZED(0),
112 /** Replica is being written to. */
113 RBW(1),
114 /** Replica is waiting to be recovered. */
115 RWR(2),
116 /** Replica is under recovery. */
117 RUR(3),
118 /** Temporary replica: created for replication and relocation only. */
119 TEMPORARY(4);
120
121 private int value;
122
123 private ReplicaState(int v) {
124 value = v;
125 }
126
127 public int getValue() {
128 return value;
129 }
130
131 public static ReplicaState getState(int v) {
132 return ReplicaState.values()[v];
133 }
134
135 /** Read from in */
136 public static ReplicaState read(DataInput in) throws IOException {
137 return values()[in.readByte()];
138 }
139
140 /** Write to out */
141 public void write(DataOutput out) throws IOException {
142 out.writeByte(ordinal());
143 }
144 }
145
146 /**
147 * States, which a block can go through while it is under construction.
148 */
149 static public enum BlockUCState {
150 /**
151 * Block construction completed.<br>
152 * The block has at least one {@link ReplicaState#FINALIZED} replica,
153 * and is not going to be modified.
154 */
155 COMPLETE,
156 /**
157 * The block is under construction.<br>
158 * It has been recently allocated for write or append.
159 */
160 UNDER_CONSTRUCTION,
161 /**
162 * The block is under recovery.<br>
163 * When a file lease expires its last block may not be {@link #COMPLETE}
164 * and needs to go through a recovery procedure,
165 * which synchronizes the existing replicas contents.
166 */
167 UNDER_RECOVERY,
168 /**
169 * The block is committed.<br>
170 * The client reported that all bytes are written to data-nodes
171 * with the given generation stamp and block length, but no
172 * {@link ReplicaState#FINALIZED}
173 * replicas has yet been reported by data-nodes themselves.
174 */
175 COMMITTED;
176 }
177
178 public static final String NAMENODE_LEASE_HOLDER = "HDFS_NameNode";
179 public static final long NAMENODE_LEASE_RECHECK_INTERVAL = 2000;
180 }
181