服务端Leader启动
1. Leader启动工作内容
2. 启动Zookeeper服务
- lead()方法 Leader.java
java
void lead() throws IOException, InterruptedException {
......
try {
......
startZkServer();
......
} finally {
......
}
}- 启动zk服务方法 Leader.java
java
private synchronized void startZkServer() {
// Update lastCommitted and Db's zxid to a value representing the new epoch
lastCommitted = zk.getZxid();
LOG.info("Have quorum of supporters, sids: [{}]; starting up and setting last processed zxid: 0x{}",
newLeaderProposal.ackSetsToString(),
Long.toHexString(zk.getZxid()));
if (self.isReconfigEnabled()) {
/*
* ZOOKEEPER-1324. the leader sends the new config it must complete
* to others inside a NEWLEADER message (see LearnerHandler where
* the NEWLEADER message is constructed), and once it has enough
* acks we must execute the following code so that it applies the
* config to itself.
*/
QuorumVerifier newQV = self.getLastSeenQuorumVerifier();
Long designatedLeader = getDesignatedLeader(newLeaderProposal, zk.getZxid());
self.processReconfig(newQV, designatedLeader, zk.getZxid(), true);
if (designatedLeader != self.getMyId()) {
LOG.warn("This leader is not the designated leader, it will be initialized with allowedToCommit = false");
allowedToCommit = false;
}
} else {
LOG.info("Dynamic reconfig feature is disabled, skip designatedLeader calculation and reconfig processing.");
}
leaderStartTime = Time.currentElapsedTime();
// 启动 Zookeeper
zk.startup();
/*
* Update the election vote here to ensure that all members of the
* ensemble report the same vote to new servers that start up and
* send leader election notifications to the ensemble.
*
* @see https://issues.apache.org/jira/browse/ZOOKEEPER-1732
*/
self.updateElectionVote(getEpoch());
zk.getZKDatabase().setlastProcessedZxid(zk.getZxid());
}- 启动方法调用父类启动 LeaderZooKeeperServer.java
java
@Override
public synchronized void startup() {
// 调用父类启动方法
super.startup();
if (containerManager != null) {
containerManager.start();
}
}- 启动具体需要的项目内容
ZooKeeperServer.java
java
public synchronized void startup() {
startupWithServerState(State.RUNNING);
}
private void startupWithServerState(State state) {
if (sessionTracker == null) {
createSessionTracker();
}
startSessionTracker();
setupRequestProcessors();
startRequestThrottler();
registerJMX();
startJvmPauseMonitor();
registerMetrics();
setState(state);
requestPathMetricsCollector.start();
localSessionEnabled = sessionTracker.isLocalSessionsEnabled();
notifyAll();
}
protected void setupRequestProcessors() {
RequestProcessor finalProcessor = new FinalRequestProcessor(this);
RequestProcessor syncProcessor = new SyncRequestProcessor(this, finalProcessor);
((SyncRequestProcessor) syncProcessor).start();
firstProcessor = new PrepRequestProcessor(this, syncProcessor);
((PrepRequestProcessor) firstProcessor).start();
}- PrepRequestProcessor是线程类，查看run()方法
PrepRequestProcessor.java
java
@Override
public void run() {
LOG.info(String.format("PrepRequestProcessor (sid:%d) started, reconfigEnabled=%s", zks.getServerId(), zks.reconfigEnabled));
try {
while (true) {
ServerMetrics.getMetrics().PREP_PROCESSOR_QUEUE_SIZE.add(submittedRequests.size());
Request request = submittedRequests.take();
ServerMetrics.getMetrics().PREP_PROCESSOR_QUEUE_TIME
.add(Time.currentElapsedTime() - request.prepQueueStartTime);
if (LOG.isTraceEnabled()) {
long traceMask = ZooTrace.CLIENT_REQUEST_TRACE_MASK;
if (request.type == OpCode.ping) {
traceMask = ZooTrace.CLIENT_PING_TRACE_MASK;
}
ZooTrace.logRequest(LOG, traceMask, 'P', request, "");
}
if (Request.requestOfDeath == request) {
break;
}
request.prepStartTime = Time.currentElapsedTime();
pRequest(request);
}
} catch (Exception e) {
handleException(this.getName(), e);
}
LOG.info("PrepRequestProcessor exited loop!");
}- 处理请求
java
protected void pRequest(Request request) throws RequestProcessorException {
// LOG.info("Prep>>> cxid = " + request.cxid + " type = " +
// request.type + " id = 0x" + Long.toHexString(request.sessionId));
request.setHdr(null);
request.setTxn(null);
if (!request.isThrottled()) {
pRequestHelper(request);
}
request.zxid = zks.getZxid();
long timeFinishedPrepare = Time.currentElapsedTime();
ServerMetrics.getMetrics().PREP_PROCESS_TIME.add(timeFinishedPrepare - request.prepStartTime);
nextProcessor.processRequest(request);
ServerMetrics.getMetrics().PROPOSAL_PROCESS_TIME.add(Time.currentElapsedTime() - timeFinishedPrepare);
}- 具体处理请求
java
private void pRequestHelper(Request request) throws RequestProcessorException {
try {
switch (request.type) {
case OpCode.createContainer:
case OpCode.create:
case OpCode.create2:
CreateRequest create2Request = new CreateRequest();
pRequest2Txn(request.type, zks.getNextZxid(), request, create2Request, true);
break;
case OpCode.createTTL:
CreateTTLRequest createTtlRequest = new CreateTTLRequest();
pRequest2Txn(request.type, zks.getNextZxid(), request, createTtlRequest, true);
break;
case OpCode.deleteContainer:
case OpCode.delete:
DeleteRequest deleteRequest = new DeleteRequest();
pRequest2Txn(request.type, zks.getNextZxid(), request, deleteRequest, true);
break;
case OpCode.setData:
SetDataRequest setDataRequest = new SetDataRequest();
pRequest2Txn(request.type, zks.getNextZxid(), request, setDataRequest, true);
break;
case OpCode.reconfig:
ReconfigRequest reconfigRequest = new ReconfigRequest();
ByteBufferInputStream.byteBuffer2Record(request.request, reconfigRequest);
pRequest2Txn(request.type, zks.getNextZxid(), request, reconfigRequest, true);
break;
case OpCode.setACL:
SetACLRequest setAclRequest = new SetACLRequest();
pRequest2Txn(request.type, zks.getNextZxid(), request, setAclRequest, true);
break;
case OpCode.check:
CheckVersionRequest checkRequest = new CheckVersionRequest();
pRequest2Txn(request.type, zks.getNextZxid(), request, checkRequest, true);
break;
case OpCode.multi:
MultiOperationRecord multiRequest = new MultiOperationRecord();
try {
ByteBufferInputStream.byteBuffer2Record(request.request, multiRequest);
} catch (IOException e) {
request.setHdr(new TxnHeader(request.sessionId, request.cxid, zks.getNextZxid(), Time.currentWallTime(), OpCode.multi));
throw e;
}
List<Txn> txns = new ArrayList<Txn>();
//Each op in a multi-op must have the same zxid!
long zxid = zks.getNextZxid();
KeeperException ke = null;
//Store off current pending change records in case we need to rollback
Map<String, ChangeRecord> pendingChanges = getPendingChanges(multiRequest);
request.setHdr(new TxnHeader(request.sessionId, request.cxid, zxid,
Time.currentWallTime(), request.type));
for (Op op : multiRequest) {
Record subrequest = op.toRequestRecord();
int type;
Record txn;
/* If we've already failed one of the ops, don't bother
* trying the rest as we know it's going to fail and it
* would be confusing in the logfiles.
*/
if (ke != null) {
type = OpCode.error;
txn = new ErrorTxn(Code.RUNTIMEINCONSISTENCY.intValue());
} else {
/* Prep the request and convert to a Txn */
try {
pRequest2Txn(op.getType(), zxid, request, subrequest, false);
type = op.getType();
txn = request.getTxn();
} catch (KeeperException e) {
ke = e;
type = OpCode.error;
txn = new ErrorTxn(e.code().intValue());
if (e.code().intValue() > Code.APIERROR.intValue()) {
LOG.info("Got user-level KeeperException when processing {} aborting"
+ " remaining multi ops. Error Path:{} Error:{}",
request.toString(),
e.getPath(),
e.getMessage());
}
request.setException(e);
/* Rollback change records from failed multi-op */
rollbackPendingChanges(zxid, pendingChanges);
}
}
// TODO: I don't want to have to serialize it here and then
// immediately deserialize in next processor. But I'm
// not sure how else to get the txn stored into our list.
try (ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
BinaryOutputArchive boa = BinaryOutputArchive.getArchive(baos);
txn.serialize(boa, "request");
ByteBuffer bb = ByteBuffer.wrap(baos.toByteArray());
txns.add(new Txn(type, bb.array()));
}
}
request.setTxn(new MultiTxn(txns));
if (digestEnabled) {
setTxnDigest(request);
}
break;
//create/close session don't require request record
case OpCode.createSession:
case OpCode.closeSession:
if (!request.isLocalSession()) {
pRequest2Txn(request.type, zks.getNextZxid(), request, null, true);
}
break;
//All the rest don't need to create a Txn - just verify session
case OpCode.sync:
case OpCode.exists:
case OpCode.getData:
case OpCode.getACL:
case OpCode.getChildren:
case OpCode.getAllChildrenNumber:
case OpCode.getChildren2:
case OpCode.ping:
case OpCode.setWatches:
case OpCode.setWatches2:
case OpCode.checkWatches:
case OpCode.removeWatches:
case OpCode.getEphemerals:
case OpCode.multiRead:
case OpCode.addWatch:
case OpCode.whoAmI:
zks.sessionTracker.checkSession(request.sessionId, request.getOwner());
break;
default:
LOG.warn("unknown type {}", request.type);
break;
}
} catch (KeeperException e) {
if (request.getHdr() != null) {
request.getHdr().setType(OpCode.error);
request.setTxn(new ErrorTxn(e.code().intValue()));
}
if (e.code().intValue() > Code.APIERROR.intValue()) {
LOG.info(
"Got user-level KeeperException when processing {} Error Path:{} Error:{}",
request.toString(),
e.getPath(),
e.getMessage());
}
request.setException(e);
} catch (Exception e) {
// log at error level as we are returning a marshalling
// error to the user
LOG.error("Failed to process {}", request, e);
StringBuilder sb = new StringBuilder();
ByteBuffer bb = request.request;
if (bb != null) {
bb.rewind();
while (bb.hasRemaining()) {
sb.append(String.format("%02x", (0xff & bb.get())));
}
} else {
sb.append("request buffer is null");
}
LOG.error("Dumping request buffer for request type {}: 0x{}", Request.op2String(request.type), sb);
if (request.getHdr() != null) {
request.getHdr().setType(OpCode.error);
request.setTxn(new ErrorTxn(Code.MARSHALLINGERROR.intValue()));
}
}
}