服务端Leader 启动
ZooKeeperServer
Leader.java
void lead() throws IOException, InterruptedException {
......
// 启动zookeeper 服务
startZkServer();
......
}
final LeaderZooKeeperServer zk;
private synchronized void startZkServer() {
// 启动 Zookeeper zk.startup();
......
}
LeaderZooKeeperServer.java
public synchronized void startup() {
super.startup();
if (containerManager != null) {
containerManager.start();
}
}
ZookeeperServer.java
public synchronized void startup() {
if (sessionTracker == null) {
createSessionTracker();
}
startSessionTracker();
setupRequestProcessors();
registerJMX();
setState(State.RUNNING);
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();
}
点击PrepRequestProcessor，并查找它的run方法
public void run() {
try {
while (true) {
Request request = submittedRequests.take();
long traceMask = ZooTrace.CLIENT_REQUEST_TRACE_MASK;
if (request.type == OpCode.ping) {
traceMask = ZooTrace.CLIENT_PING_TRACE_MASK;
}
if (LOG.isTraceEnabled()) {
ZooTrace.logRequest(LOG, traceMask, 'P', request, "");
}
if (Request.requestOfDeath == request) {
break;
}
pRequest(request);
}
} catch (RequestProcessorException e) {
if (e.getCause() instanceof XidRolloverException) {
LOG.info(e.getCause().getMessage());
}
handleException(this.getName(), e);
} catch (Exception e) {
handleException(this.getName(), e);
}
LOG.info("PrepRequestProcessor exited loop!");
}
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);
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:
MultiTransactionRecord multiRequest = new MultiTransactionRecord();
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);
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());
}
/* Prep the request and convert to a Txn */
else {
try {
pRequest2Txn(op.getType(), zxid, request, subrequest, false);
type = request.getHdr().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);
}
}
//FIXME: 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.
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.setHdr(new TxnHeader(request.sessionId, request.cxid, zxid,
Time.currentWallTime(), request.type));
request.setTxn(new MultiTxn(txns));
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.getChildren2:
case OpCode.ping:
case OpCode.setWatches:
case OpCode.checkWatches:
case OpCode.removeWatches:
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(Integer.toHexString(bb.get() & 0xff));
}
} else {
sb.append("request buffer is null");
}
LOG.error("Dumping request buffer: 0x" + sb.toString());
if (request.getHdr() != null) {
request.getHdr().setType(OpCode.error);
request.setTxn(new ErrorTxn(Code.MARSHALLINGERROR.intValue()));
}
}
request.zxid = zks.getZxid();
nextProcessor.processRequest(request);
}
服务端Follower 启动
FollowerZooKeeperServer
Ctrl + n 全局查找Follower，然后ctrl + f 查找followLeader
void followLeader() throws InterruptedException {
self.end_fle = Time.currentElapsedTime();
long electionTimeTaken = self.end_fle - self.start_fle;
self.setElectionTimeTaken(electionTimeTaken);
LOG.info("FOLLOWING - LEADER ELECTION TOOK - {} {}", electionTimeTaken,
QuorumPeer.FLE_TIME_UNIT);
self.start_fle = 0;
self.end_fle = 0;
fzk.registerJMX(new FollowerBean(this, zk), self.jmxLocalPeerBean);
try {
QuorumServer leaderServer = findLeader();
try {
connectToLeader(leaderServer.addr, leaderServer.hostname);
long newEpochZxid = registerWithLeader(Leader.FOLLOWERINFO);
if (self.isReconfigStateChange())
throw new Exception("learned about role change");
//check to see if the leader zxid is lower than ours
//this should never happen but is just a safety check
long newEpoch = ZxidUtils.getEpochFromZxid(newEpochZxid);
if (newEpoch < self.getAcceptedEpoch()) {
LOG.error("Proposed leader epoch " + ZxidUtils.zxidToString(newEpochZxid)
+ " is less than our accepted epoch " + ZxidUtils.zxidToString(self.getAcceptedEpoch()));
throw new IOException("Error: Epoch of leader is lower");
}
syncWithLeader(newEpochZxid);
QuorumPacket qp = new QuorumPacket();
while (this.isRunning()) {
readPacket(qp);
processPacket(qp);
}
} catch (Exception e) {
...
}
} finally {
zk.unregisterJMX((Learner)this);
}
}
void readPacket(QuorumPacket pp) throws IOException {
synchronized (leaderIs) {
leaderIs.readRecord(pp, "packet");
}
if (LOG.isTraceEnabled()) {
final long traceMask =
(pp.getType() == Leader.PING) ? ZooTrace.SERVER_PING_TRACE_MASK
: ZooTrace.SERVER_PACKET_TRACE_MASK;
ZooTrace.logQuorumPacket(LOG, traceMask, 'i', pp);
}
}
protected void processPacket(QuorumPacket qp) throws Exception{
switch (qp.getType()) {
case Leader.PING:
ping(qp);
break;
case Leader.PROPOSAL:
TxnHeader hdr = new TxnHeader();
Record txn = SerializeUtils.deserializeTxn(qp.getData(), hdr);
if (hdr.getZxid() != lastQueued + 1) {
LOG.warn("Got zxid 0x"
+ Long.toHexString(hdr.getZxid())
+ " expected 0x"
+ Long.toHexString(lastQueued + 1));
}
lastQueued = hdr.getZxid();
if (hdr.getType() == OpCode.reconfig){
SetDataTxn setDataTxn = (SetDataTxn) txn;
QuorumVerifier qv = self.configFromString(new String(setDataTxn.getData()));
self.setLastSeenQuorumVerifier(qv, true);
}
fzk.logRequest(hdr, txn);
break;
case Leader.COMMIT:
fzk.commit(qp.getZxid());
break;
case Leader.COMMITANDACTIVATE:
// get the new configuration from the request
Request request = fzk.pendingTxns.element();
SetDataTxn setDataTxn = (SetDataTxn) request.getTxn();
QuorumVerifier qv = self.configFromString(new String(setDataTxn.getData()));
// get new designated leader from (current) leader's message
ByteBuffer buffer = ByteBuffer.wrap(qp.getData());
long suggestedLeaderId = buffer.getLong();
boolean majorChange =
self.processReconfig(qv, suggestedLeaderId, qp.getZxid(), true);
// commit (writes the new config to ZK tree (/zookeeper/config)
fzk.commit(qp.getZxid());
if (majorChange) {
throw new Exception("changes proposed in reconfig");
}
break;
case Leader.UPTODATE:
LOG.error("Received an UPTODATE message after Follower started");
break;
case Leader.REVALIDATE:
revalidate(qp);
break;
case Leader.SYNC:
fzk.sync();
break;
default:
LOG.warn("Unknown packet type: {}", LearnerHandler.packetToString(qp));
break;
}
}
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