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ZOOKEEPER-3863: Do not track global sessions in ReadOnlyZooKeeperServer #1380

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jhuan31 wants to merge 4 commits into from
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ZOOKEEPER-3863: Do not track global sessions in ReadOnlyZooKeeperServer #1380

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b67f1c1
ZOOKEEPER-3863: Do not track global sessions in ReadOnlyZooKeeperServer
Jun 15, 2020
f160caa
ZOOKEEPER-3864: Reject create/renew/close global session in RO mode
Jun 22, 2020
8f62a8d
fix ReadOnlyModeTest
Jun 22, 2020
80fb3cf
add a test for global sessions in RO mode
Jun 23, 2020
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3 changes: 2 additions & 1 deletion zookeeper-server/src/main/java/org/apache/zookeeper/server/ServerCnxn.java
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Original file line number Diff line number Diff line change
Expand Up @@ -101,6 +101,7 @@ public enum DisconnectReason {
CLOSE_CONNECTION_COMMAND("close_connection_command"),
CLEAN_UP("clean_up"),
CONNECTION_MODE_CHANGED("connection_mode_changed"),
RENEW_GLOBAL_SESSION_IN_RO_MODE("renew a global session in readonly mode"),
// Below reasons are NettyServerCnxnFactory only
CHANNEL_DISCONNECTED("channel disconnected"),
CHANNEL_CLOSED_EXCEPTION("channel_closed_exception"),
Expand Down Expand Up @@ -298,7 +299,7 @@ void disableRecv() {

protected ZooKeeperSaslServer zooKeeperSaslServer = null;

protected static class CloseRequestException extends IOException {
public static class CloseRequestException extends IOException {

private static final long serialVersionUID = -7854505709816442681L;
private DisconnectReason reason;
Expand Down
25 changes: 18 additions & 7 deletions zookeeper-server/src/main/java/org/apache/zookeeper/server/ZooKeeperServer.java
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Original file line number Diff line number Diff line change
Expand Up @@ -1413,13 +1413,13 @@ public void processConnectRequest(ServerCnxn cnxn, ByteBuffer incomingBuffer)
connReq.getTimeOut(),
cnxn.getRemoteSocketAddress());
} else {
long clientSessionId = connReq.getSessionId();
LOG.debug(
"Client attempting to renew session: session = 0x{}, zxid = 0x{}, timeout = {}, address = {}",
Long.toHexString(clientSessionId),
Long.toHexString(connReq.getLastZxidSeen()),
connReq.getTimeOut(),
cnxn.getRemoteSocketAddress());
validateSession(cnxn, sessionId);
LOG.debug(
"Client attempting to renew session: session = 0x{}, zxid = 0x{}, timeout = {}, address = {}",
Long.toHexString(sessionId),
Long.toHexString(connReq.getLastZxidSeen()),
connReq.getTimeOut(),
cnxn.getRemoteSocketAddress());
if (serverCnxnFactory != null) {
serverCnxnFactory.closeSession(sessionId, ServerCnxn.DisconnectReason.CLIENT_RECONNECT);
}
Expand All @@ -1433,6 +1433,17 @@ public void processConnectRequest(ServerCnxn cnxn, ByteBuffer incomingBuffer)
}
}

/**
* Validate if a particular session can be reestablished.
*
* @param cnxn
* @param sessionId
*/
protected void validateSession(ServerCnxn cnxn, long sessionId)
throws IOException {
// do nothing
}

public boolean shouldThrottle(long outStandingCount) {
int globalOutstandingLimit = getGlobalOutstandingLimit();
if (globalOutstandingLimit < getInflight() || globalOutstandingLimit < getInProcess()) {
Expand Down
28 changes: 19 additions & 9 deletions ...per-server/src/main/java/org/apache/zookeeper/server/quorum/ReadOnlyRequestProcessor.java
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Original file line number Diff line number Diff line change
Expand Up @@ -86,16 +86,14 @@ public void run() {
case OpCode.setACL:
case OpCode.multi:
case OpCode.check:
ReplyHeader hdr = new ReplyHeader(
request.cxid,
zks.getZKDatabase().getDataTreeLastProcessedZxid(),
Code.NOTREADONLY.intValue());
try {
request.cnxn.sendResponse(hdr, null, null);
} catch (IOException e) {
LOG.error("IO exception while sending response", e);
}
sendErrorResponse(request);
continue;
case OpCode.closeSession:
case OpCode.createSession:
if (!request.isLocalSession()) {
sendErrorResponse(request);
continue;
}
}

// proceed to the next processor
Expand All @@ -109,6 +107,18 @@ public void run() {
LOG.info("ReadOnlyRequestProcessor exited loop!");
}

private void sendErrorResponse(Request request) {
ReplyHeader hdr = new ReplyHeader(
request.cxid,
zks.getZKDatabase().getDataTreeLastProcessedZxid(),
Code.NOTREADONLY.intValue());
try {
request.cnxn.sendResponse(hdr, null, null);
} catch (IOException e) {
LOG.error("IO exception while sending response", e);
}
}

@Override
public void processRequest(Request request) {
if (!finished) {
Expand Down
47 changes: 47 additions & 0 deletions ...eper-server/src/main/java/org/apache/zookeeper/server/quorum/ReadOnlyZooKeeperServer.java
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Original file line number Diff line number Diff line change
Expand Up @@ -18,14 +18,18 @@

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;
Expand Down Expand Up @@ -80,6 +84,49 @@ public synchronized void startup() {
LOG.info("Read-only server started");
}

@Override
public void createSessionTracker() {
sessionTracker = new LearnerSessionTracker(
this, getZKDatabase().getSessionWithTimeOuts(),
this.tickTime, self.getId(), 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
Expand Down
57 changes: 56 additions & 1 deletion zookeeper-server/src/test/java/org/apache/zookeeper/test/ReadOnlyModeTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@
import java.io.ByteArrayOutputStream;
import java.io.LineNumberReader;
import java.io.StringReader;
import java.util.concurrent.TimeoutException;
import java.util.regex.Pattern;
import org.apache.log4j.Layout;
import org.apache.log4j.Level;
Expand Down Expand Up @@ -56,7 +57,6 @@ public class ReadOnlyModeTest extends ZKTestCase {
@Before
public void setUp() throws Exception {
System.setProperty("readonlymode.enabled", "true");
qu.startQuorum();
}

@After
Expand All @@ -70,6 +70,9 @@ public void tearDown() throws Exception {
*/
@Test(timeout = 90000)
public void testMultiTransaction() throws Exception {
qu.enableLocalSession(true);
qu.startQuorum();

CountdownWatcher watcher = new CountdownWatcher();
ZooKeeper zk = new ZooKeeper(qu.getConnString(), CONNECTION_TIMEOUT, watcher, true);
watcher.waitForConnected(CONNECTION_TIMEOUT); // ensure zk got connected
Expand All @@ -78,9 +81,12 @@ public void testMultiTransaction() throws Exception {
final String node1 = "/tnode1";
final String node2 = "/tnode2";
zk.create(node1, data.getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
zk.close();
watcher.waitForDisconnected(CONNECTION_TIMEOUT);

watcher.reset();
qu.shutdown(2);
zk = new ZooKeeper(qu.getConnString(), CONNECTION_TIMEOUT, watcher, true);
watcher.waitForConnected(CONNECTION_TIMEOUT);
assertEquals("Should be in r-o mode", States.CONNECTEDREADONLY, zk.getState());

Expand All @@ -107,6 +113,9 @@ public void testMultiTransaction() throws Exception {
*/
@Test(timeout = 90000)
public void testReadOnlyClient() throws Exception {
qu.enableLocalSession(true);
qu.startQuorum();

CountdownWatcher watcher = new CountdownWatcher();
ZooKeeper zk = new ZooKeeper(qu.getConnString(), CONNECTION_TIMEOUT, watcher, true);
watcher.waitForConnected(CONNECTION_TIMEOUT); // ensure zk got connected
Expand Down Expand Up @@ -158,6 +167,9 @@ public void testReadOnlyClient() throws Exception {
*/
@Test(timeout = 90000)
public void testConnectionEvents() throws Exception {
qu.enableLocalSession(true);
qu.startQuorum();

CountdownWatcher watcher = new CountdownWatcher();
ZooKeeper zk = new ZooKeeper(qu.getConnString(), CONNECTION_TIMEOUT, watcher, true);
boolean success = false;
Expand Down Expand Up @@ -198,6 +210,9 @@ public void testConnectionEvents() throws Exception {
*/
@Test(timeout = 90000)
public void testSessionEstablishment() throws Exception {
qu.enableLocalSession(true);
qu.startQuorum();

qu.shutdown(2);

CountdownWatcher watcher = new CountdownWatcher();
Expand Down Expand Up @@ -227,13 +242,53 @@ public void testSessionEstablishment() throws Exception {
zk.close();
}

@Test(timeout = 90000)
public void testGlobalSessionInRO() throws Exception {
qu.startQuorum();

CountdownWatcher watcher = new CountdownWatcher();
ZooKeeper zk = new ZooKeeper(qu.getConnString(), CONNECTION_TIMEOUT, watcher, true);
watcher.waitForConnected(CONNECTION_TIMEOUT);
LOG.info("global session created 0x{}", Long.toHexString(zk.getSessionId()));

watcher.reset();
qu.shutdown(2);
try {
watcher.waitForConnected(CONNECTION_TIMEOUT);
fail("Should not be able to renew a global session");
} catch (TimeoutException e) {
}
zk.close();

watcher.reset();
zk = new ZooKeeper(qu.getConnString(), CONNECTION_TIMEOUT, watcher, true);
try {
watcher.waitForConnected(CONNECTION_TIMEOUT);
fail("Should not be able to create a global session");
} catch (TimeoutException e) {
}
zk.close();

qu.getPeer(1).peer.enableLocalSessions(true);
zk = new ZooKeeper(qu.getConnString(), CONNECTION_TIMEOUT, watcher, true);
try {
watcher.waitForConnected(CONNECTION_TIMEOUT);
} catch (TimeoutException e) {
fail("Should be able to create a local session");
}
zk.close();
}

/**
* Ensures that client seeks for r/w servers while it's connected to r/o
* server.
*/
@SuppressWarnings("deprecation")
@Test(timeout = 90000)
public void testSeekForRwServer() throws Exception {
qu.enableLocalSession(true);
qu.startQuorum();

// setup the logger to capture all logs
Layout layout = Logger.getRootLogger().getAppender("CONSOLE").getLayout();
ByteArrayOutputStream os = new ByteArrayOutputStream();
Expand Down