1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
|
/*
* 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.zookeeper.server.quorum;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Objects;
import java.util.stream.Collectors;
import org.apache.zookeeper.ZooDefs.OpCode;
import org.apache.zookeeper.jmx.MBeanRegistry;
import org.apache.zookeeper.server.DataTreeBean;
import org.apache.zookeeper.server.FinalRequestProcessor;
import org.apache.zookeeper.server.PrepRequestProcessor;
import org.apache.zookeeper.server.Request;
import org.apache.zookeeper.server.RequestProcessor;
import org.apache.zookeeper.server.ServerCnxn;
import org.apache.zookeeper.server.ZKDatabase;
import org.apache.zookeeper.server.ZooKeeperServer;
import org.apache.zookeeper.server.ZooKeeperServerBean;
import org.apache.zookeeper.server.persistence.FileTxnSnapLog;
/**
* A ZooKeeperServer which comes into play when peer is partitioned from the
* majority. Handles read-only clients, but drops connections from not-read-only
* ones.
* <p>
* The very first processor in the chain of request processors is a
* ReadOnlyRequestProcessor which drops state-changing requests.
*/
public class ReadOnlyZooKeeperServer extends ZooKeeperServer {
protected final QuorumPeer self;
private volatile boolean shutdown = false;
ReadOnlyZooKeeperServer(FileTxnSnapLog logFactory, QuorumPeer self, ZKDatabase zkDb) {
super(
logFactory,
self.tickTime,
self.minSessionTimeout,
self.maxSessionTimeout,
self.clientPortListenBacklog,
zkDb,
self.getInitialConfig(),
self.isReconfigEnabled());
this.self = self;
}
@Override
protected void setupRequestProcessors() {
RequestProcessor finalProcessor = new FinalRequestProcessor(this);
RequestProcessor prepProcessor = new PrepRequestProcessor(this, finalProcessor);
((PrepRequestProcessor) prepProcessor).start();
firstProcessor = new ReadOnlyRequestProcessor(this, prepProcessor);
((ReadOnlyRequestProcessor) firstProcessor).start();
}
@Override
public synchronized void startup() {
// check to avoid startup follows shutdown
if (shutdown) {
LOG.warn("Not starting Read-only server as startup follows shutdown!");
return;
}
registerJMX(new ReadOnlyBean(this), self.jmxLocalPeerBean);
super.startup();
self.setZooKeeperServer(this);
self.adminServer.setZooKeeperServer(this);
LOG.info("Read-only server started");
}
@Override
public void createSessionTracker() {
sessionTracker = new LearnerSessionTracker(
this, getZKDatabase().getSessionWithTimeOuts(),
this.tickTime, self.getMyId(), self.areLocalSessionsEnabled(),
getZooKeeperServerListener());
}
@Override
protected void startSessionTracker() {
((LearnerSessionTracker) sessionTracker).start();
}
@Override
protected void setLocalSessionFlag(Request si) {
switch (si.type) {
case OpCode.createSession:
if (self.areLocalSessionsEnabled()) {
si.setLocalSession(true);
}
break;
case OpCode.closeSession:
if (((UpgradeableSessionTracker) sessionTracker).isLocalSession(si.sessionId)) {
si.setLocalSession(true);
} else {
LOG.warn("Submitting global closeSession request for session 0x{} in ReadOnly mode",
Long.toHexString(si.sessionId));
}
break;
default:
break;
}
}
@Override
protected void validateSession(ServerCnxn cnxn, long sessionId) throws IOException {
if (((LearnerSessionTracker) sessionTracker).isGlobalSession(sessionId)) {
String msg = "Refusing global session reconnection in RO mode " + cnxn.getRemoteSocketAddress();
LOG.info(msg);
throw new ServerCnxn.CloseRequestException(msg, ServerCnxn.DisconnectReason.RENEW_GLOBAL_SESSION_IN_RO_MODE);
}
}
@Override
protected void registerJMX() {
// register with JMX
try {
jmxDataTreeBean = new DataTreeBean(getZKDatabase().getDataTree());
MBeanRegistry.getInstance().register(jmxDataTreeBean, jmxServerBean);
} catch (Exception e) {
LOG.warn("Failed to register with JMX", e);
jmxDataTreeBean = null;
}
}
public void registerJMX(ZooKeeperServerBean serverBean, LocalPeerBean localPeerBean) {
// register with JMX
try {
jmxServerBean = serverBean;
MBeanRegistry.getInstance().register(serverBean, localPeerBean);
} catch (Exception e) {
LOG.warn("Failed to register with JMX", e);
jmxServerBean = null;
}
}
@Override
protected void unregisterJMX() {
// unregister from JMX
try {
if (jmxDataTreeBean != null) {
MBeanRegistry.getInstance().unregister(jmxDataTreeBean);
}
} catch (Exception e) {
LOG.warn("Failed to unregister with JMX", e);
}
jmxDataTreeBean = null;
}
protected void unregisterJMX(ZooKeeperServer zks) {
// unregister from JMX
try {
if (jmxServerBean != null) {
MBeanRegistry.getInstance().unregister(jmxServerBean);
}
} catch (Exception e) {
LOG.warn("Failed to unregister with JMX", e);
}
jmxServerBean = null;
}
@Override
public String getState() {
return "read-only";
}
/**
* Returns the id of the associated QuorumPeer, which will do for a unique
* id of this server.
*/
@Override
public long getServerId() {
return self.getMyId();
}
@Override
public synchronized void shutdown() {
if (!canShutdown()) {
LOG.debug("ZooKeeper server is not running, so not proceeding to shutdown!");
return;
}
shutdown = true;
unregisterJMX(this);
// set peer's server to null
self.setZooKeeperServer(null);
// clear all the connections
self.closeAllConnections();
self.adminServer.setZooKeeperServer(null);
// shutdown the server itself
super.shutdown();
}
@Override
public void dumpConf(PrintWriter pwriter) {
super.dumpConf(pwriter);
pwriter.print("initLimit=");
pwriter.println(self.getInitLimit());
pwriter.print("syncLimit=");
pwriter.println(self.getSyncLimit());
pwriter.print("electionAlg=");
pwriter.println(self.getElectionType());
pwriter.print("electionPort=");
pwriter.println(self.getElectionAddress().getAllPorts()
.stream().map(Objects::toString).collect(Collectors.joining("|")));
pwriter.print("quorumPort=");
pwriter.println(self.getQuorumAddress().getAllPorts()
.stream().map(Objects::toString).collect(Collectors.joining("|")));
pwriter.print("peerType=");
pwriter.println(self.getLearnerType().ordinal());
}
@Override
protected void setState(State state) {
this.state = state;
}
}
|
