03、ZooKeeper 服务端启动
时序图
todo
源码
// QuorumPeerMain
public static void main(String[] args) {
QuorumPeerMain main = new QuorumPeerMain();
try {
main.initializeAndRun(args);
} catch (IllegalArgumentException e) {
LOG.error("Invalid arguments, exiting abnormally", e);
LOG.info(USAGE);
System.err.println(USAGE);
System.exit(2);
} catch (ConfigException e) {
LOG.error("Invalid config, exiting abnormally", e);
System.err.println("Invalid config, exiting abnormally");
System.exit(2);
} catch (DatadirException e) {
LOG.error("Unable to access datadir, exiting abnormally", e);
System.err.println("Unable to access datadir, exiting abnormally");
System.exit(3);
} catch (AdminServerException e) {
LOG.error("Unable to start AdminServer, exiting abnormally", e);
System.err.println("Unable to start AdminServer, exiting abnormally");
System.exit(4);
} catch (Exception e) {
LOG.error("Unexpected exception, exiting abnormally", e);
System.exit(1);
}
LOG.info("Exiting normally");
System.exit(0);
}
// QuorumPeerMain
protected void initializeAndRun(String[] args)
throws ConfigException, IOException, AdminServerException
{
// 1. args[0]代表配置文件的路径，读取配置文件，加载到QuorumPeerConfig中
QuorumPeerConfig config = new QuorumPeerConfig();
if (args.length == 1) {
config.parse(args[0]);
}
// Start and schedule the the purge task
// 2. 启动清理任务
DatadirCleanupManager purgeMgr = new DatadirCleanupManager(config
.getDataDir(), config.getDataLogDir(), config
.getSnapRetainCount(), config.getPurgeInterval());
purgeMgr.start();
// 3. 判断是否是集群模式
if (args.length == 1 && config.isDistributed()) {
// 集群模式运行
runFromConfig(config);
} else {
LOG.warn("Either no config or no quorum defined in config, running "
+ " in standalone mode");
// there is only server in the quorum -- run as standalone
// 当前只有一个节点，切换到standalone模式
// 单机模式运行
ZooKeeperServerMain.main(args);
}
}
解析配置文件
// QuorumPeerConfig
public void parse(String path) throws ConfigException {
LOG.info("Reading configuration from: " + path);
try {
// 根据路径，读取配置文件
File configFile = (new VerifyingFileFactory.Builder(LOG)
.warnForRelativePath()
.failForNonExistingPath()
.build()).create(path);
// 将配置文件中的每一行解析成键值对，放到properties中
Properties cfg = new Properties();
FileInputStream in = new FileInputStream(configFile);
try {
cfg.load(in);
configFileStr = path;
} finally {
in.close();
}
// 获取Properties中的键值对，设置到QuorumPeerConfig对应的属性上
// 后续QuorumPeer的启动会使用到这些属性
parseProperties(cfg);
} catch (IOException e) {
throw new ConfigException("Error processing " + path, e);
} catch (IllegalArgumentException e) {
throw new ConfigException("Error processing " + path, e);
}
// 省略
}
// QuorumPeerConfig
public void parseProperties(Properties zkProp)
throws IOException, ConfigException {
int clientPort = 0;
int secureClientPort = 0;
String clientPortAddress = null;
String secureClientPortAddress = null;
VerifyingFileFactory vff = new VerifyingFileFactory.Builder(LOG).warnForRelativePath().build();
// 遍历properties中的键值对，设置到QuorumPeerConfig的属性上
for (Entry<Object, Object> entry : zkProp.entrySet()) {
String key = entry.getKey().toString().trim();
String value = entry.getValue().toString().trim();
if (key.equals("dataDir")) {
dataDir = vff.create(value);
} else if (key.equals("dataLogDir")) {
dataLogDir = vff.create(value);
}
// 省略
}
if (dynamicConfigFileStr == null) {
// 设置QuorumPeerConfig的配置
setupQuorumPeerConfig(zkProp, true);
if (isDistributed() && isReconfigEnabled()) {
// we don't backup static config for standalone mode.
// we also don't backup if reconfig feature is disabled.
backupOldConfig();
}
}
}
下面看下如何设置QuorumPeer
// QuorumPeerConfig
void setupQuorumPeerConfig(Properties prop, boolean configBackwardCompatibilityMode)
throws IOException, ConfigException {
// 1. 创建QuorumVerifier，对不同部署模式下参与者和观察者的数量进行校验
quorumVerifier = parseDynamicConfig(pr op, electionAlg, true, configBackwardCompatibilityMode);
// 2. 设置myid
setupMyId();
// 3. 设置客户端连接端口
setupClientPort();
// 4. 设置当前节点类型
setupPeerType();
// 5. 校验配置合法性
checkValidity();
}
parseDynamicConfig
public static QuorumVerifier parseDynamicConfig(Properties dynamicConfigProp, int eAlg, boolean warnings,
boolean configBackwardCompatibilityMode) throws IOException, ConfigException {
boolean isHierarchical = false;
for (Entry<Object, Object> entry : dynamicConfigProp.entrySet()) {
String key = entry.getKey().toString().trim();
if (key.startsWith("group") || key.startsWith("weight")) {
isHierarchical = true;
} else if (!configBackwardCompatibilityMode && !key.startsWith("server.") && !key.equals("version")){
LOG.info(dynamicConfigProp.toString());
throw new ConfigException("Unrecognised parameter: " + key);
}
}
// 根据isHierarchical来决定创建的类型，一般情况下isHierarchical都是false，此时会创建QuorumMaj
QuorumVerifier qv = createQuorumVerifier(dynamicConfigProp, isHierarchical);
// 参与投票的节点个数
int numParticipators = qv.getVotingMembers().size();
// 不参与投票的节点Observer的个数
int numObservers = qv.getObservingMembers().size();
// 不同部署模式下进行校验
if (numParticipators == 0) {
// 不允许使用单机模式，并且当前没有participator直接报错
if (!standaloneEnabled) {
throw new IllegalArgumentException("standaloneEnabled = false then " +
"number of participants should be >0");
}
// 没有participator的情况下，不允许有observer
if (numObservers > 0) {
throw new IllegalArgumentException("Observers w/o participants is an invalid configuration");
}
} else if (numParticipators == 1 && standaloneEnabled) {
// 允许单机部署并且participator的个数为1，此时obsserver的个数不能为0
// HBase currently adds a single server line to the config, for
// b/w compatibility reasons we need to keep this here. If standaloneEnabled
// is true, the QuorumPeerMain script will create a standalone server instead
// of a quorum configuration
LOG.error("Invalid configuration, only one server specified (ignoring)");
if (numObservers > 0) {
throw new IllegalArgumentException("Observers w/o quorum is an invalid configuration");
}
} else {
// 对participator参与投票的节点的个数进行验证，如果《=2或者格式不是计数，会在日志中进行提醒
if (warnings) {
if (numParticipators <= 2) {
LOG.warn("No server failure will be tolerated. " +
"You need at least 3 servers.");
} else if (numParticipators % 2 == 0) {
LOG.warn("Non-optimial configuration, consider an odd number of servers.");
}
}
/*
* If using FLE, then every server requires a separate election
* port.
*/
if (eAlg != 0) {
// 校验参与选举的节点是否都设置了选举端口
for (QuorumServer s : qv.getVotingMembers().values()) {
if (s.electionAddr == null)
throw new IllegalArgumentException(
"Missing election port for server: " + s.id);
}
}
}
return qv;
}
下面看下如何创建QuorumMaj
QuorumMaj中保存当前中有哪些节点，以及这些节点的id，并标识哪些节点是参与投票的，哪些节点是观察者不参与投票
// QuorumMaj
public QuorumMaj(Properties props) throws ConfigException {
// 遍历配置项
for (Entry<Object, Object> entry : props.entrySet()) {
String key = entry.getKey().toString();
String value = entry.getValue().toString();
// 比如server.1 server.2 指定集群中各个服务端节点的地址，各种连接端口的配置
if (key.startsWith("server.")) {
int dot = key.indexOf('.');
// 获取id
long sid = Long.parseLong(key.substring(dot + 1));
// QuorumServer封装了服务端节点的ip和各种端口
QuorumServer qs = new QuorumServer(sid, value);
// 创建id->节点之间的映射
allMembers.put(Long.valueOf(sid), qs);
// 默认情况下是PARTICIPANT
if (qs.type == LearnerType.PARTICIPANT)
votingMembers.put(Long.valueOf(sid), qs);
else {
observingMembers.put(Long.valueOf(sid), qs);
}
} else if (key.equals("version")) {
version = Long.parseLong(value, 16);
}
}
half = votingMembers.size() / 2;
}
setupMyId
从配置文件中读取当前节点的id
将dataDir下myid文件中的内容作为当前节点的id
// QuorumPeerConfig
private void setupMyId() throws IOException {
File myIdFile = new File(dataDir, "myid");
// standalone server doesn't need myid file.
if (!myIdFile.isFile()) {
return;
}
BufferedReader br = new BufferedReader(new FileReader(myIdFile));
String myIdString;
try {
myIdString = br.readLine();
} finally {
br.close();
}
try {
serverId = Long.parseLong(myIdString);
MDC.put("myid", myIdString);
} catch (NumberFormatException e) {
throw new IllegalArgumentException("serverid " + myIdString
+ " is not a number");
}
}
setupClientPort
设置客户端连接端口
从配置文件的解析结果中根据id获取当前节点的客户端连接端口
private void setupClientPort() throws ConfigException {
if (serverId == UNSET_SERVERID) {
return;
}
QuorumServer qs = quorumVerifier.getAllMembers().get(serverId);
if (clientPortAddress != null && qs != null && qs.clientAddr != null) {
if ((!clientPortAddress.getAddress().isAnyLocalAddress()
&& !clientPortAddress.equals(qs.clientAddr)) ||
(clientPortAddress.getAddress().isAnyLocalAddress()
&& clientPortAddress.getPort() != qs.clientAddr.getPort()))
throw new ConfigException("client address for this server (id = " + serverId +
") in static config file is " + clientPortAddress +
" is different from client address found in dynamic file: " + qs.clientAddr);
}
if (qs != null && qs.clientAddr != null) clientPortAddress = qs.clientAddr;
}
setupPeerType
设置当前节点的角色
// QuorumPeerConfig
private void setupPeerType() {
// Warn about inconsistent peer type
// 判断当前节点是否是observer
LearnerType roleByServersList = quorumVerifier.getObservingMembers().containsKey(serverId) ? LearnerType.OBSERVER
: LearnerType.PARTICIPANT;
if (roleByServersList != peerType) {
LOG.warn("Peer type from servers list (" + roleByServersList
+ ") doesn't match peerType (" + peerType
+ "). Defaulting to servers list.");
peerType = roleByServersList;
}
}
checkValidity
// QuorumPeerConfig
public void checkValidity() throws IOException, ConfigException{
// 当前是分布式部署
// 对一些配置进行校验
if (isDistributed()) {
if (initLimit == 0) {
throw new IllegalArgumentException("initLimit is not set");
}
if (syncLimit == 0) {
throw new IllegalArgumentException("syncLimit is not set");
}
if (serverId == UNSET_SERVERID) {
throw new IllegalArgumentException("myid file is missing");
}
}
}
启动清理任务
todo
启动QuorumPeer
// QuorumPeerMain
public void runFromConfig(QuorumPeerConfig config)
throws IOException, AdminServerException
{
try {
ManagedUtil.registerLog4jMBeans();
} catch (JMException e) {
LOG.warn("Unable to register log4j JMX control", e);
}
LOG.info("Starting quorum peer");
// 首先读取配置，将配置中的信息设置到QuorumPeer中
// ServerCnxnFactory用来管理和客户端的连接
try {
ServerCnxnFactory cnxnFactory = null;
ServerCnxnFactory secureCnxnFactory = null;
// 从配置中取出客户端的连接地址和最大客户端连接数来创建cnxnFactory
if (config.getClientPortAddress() != null) {
cnxnFactory = ServerCnxnFactory.createFactory();
cnxnFactory.configure(config.getClientPortAddress(),
config.getMaxClientCnxns(),
false);
}
// 如果配置使用安全连接，会从配置中取出客户端安全连接地址和最大连接数来创建secureCnxnFactory
if (config.getSecureClientPortAddress() != null) {
secureCnxnFactory = ServerCnxnFactory.createFactory();
secureCnxnFactory.configure(config.getSecureClientPortAddress(),
config.getMaxClientCnxns(),
true);
}
quorumPeer = getQuorumPeer();
// 使用配置中的dataLogDir和dataDir来创建事务快照日志
quorumPeer.setTxnFactory(new FileTxnSnapLog(
config.getDataLogDir(),
config.getDataDir()));
quorumPeer.enableLocalSessions(config.areLocalSessionsEnabled());
quorumPeer.enableLocalSessionsUpgrading(
config.isLocalSessionsUpgradingEnabled());
//quorumPeer.setQuorumPeers(config.getAllMembers());
quorumPeer.setElectionType(config.getElectionAlg());
quorumPeer.setMyid(config.getServerId());
quorumPeer.setTickTime(config.getTickTime());
quorumPeer.setMinSessionTimeout(config.getMinSessionTimeout());
quorumPeer.setMaxSessionTimeout(config.getMaxSessionTimeout());
quorumPeer.setInitLimit(config.getInitLimit());
quorumPeer.setSyncLimit(config.getSyncLimit());
quorumPeer.setConfigFileName(config.getConfigFilename());
// 创建数据库
quorumPeer.setZKDatabase(new ZKDatabase(quorumPeer.getTxnFactory()));
quorumPeer.setQuorumVerifier(config.getQuorumVerifier(), false);
if (config.getLastSeenQuorumVerifier()!=null) {
quorumPeer.setLastSeenQuorumVerifier(config.getLastSeenQuorumVerifier(), false);
}
quorumPeer.initConfigInZKDatabase();
quorumPeer.setCnxnFactory(cnxnFactory);
quorumPeer.setSecureCnxnFactory(secureCnxnFactory);
quorumPeer.setSslQuorum(config.isSslQuorum());
quorumPeer.setUsePortUnification(config.shouldUsePortUnification());
quorumPeer.setLearnerType(config.getPeerType());
quorumPeer.setSyncEnabled(config.getSyncEnabled());
quorumPeer.setQuorumListenOnAllIPs(config.getQuorumListenOnAllIPs());
if (config.sslQuorumReloadCertFiles) {
quorumPeer.getX509Util().enableCertFileReloading();
}
// sets quorum sasl authentication configurations
quorumPeer.setQuorumSaslEnabled(config.quorumEnableSasl);
if(quorumPeer.isQuorumSaslAuthEnabled()){
quorumPeer.setQuorumServerSaslRequired(config.quorumServerRequireSasl);
quorumPeer.setQuorumLearnerSaslRequired(config.quorumLearnerRequireSasl);
quorumPeer.setQuorumServicePrincipal(config.quorumServicePrincipal);
quorumPeer.setQuorumServerLoginContext(config.quorumServerLoginContext);
quorumPeer.setQuorumLearnerLoginContext(config.quorumLearnerLoginContext);
}
quorumPeer.setQuorumCnxnThreadsSize(config.quorumCnxnThreadsSize);
quorumPeer.initialize();
// 启动QuorumPeer
quorumPeer.start();
quorumPeer.join();
} catch (InterruptedException e) {
// warn, but generally this is ok
LOG.warn("Quorum Peer interrupted", e);
}
}
public synchronized void start() {
if (!getView().containsKey(myid)) {
throw new RuntimeException("My id " + myid + " not in the peer list");
}
// 1. 加载数据库
loadDataBase();
// 2. 启动客户端连接管理工厂
startServerCnxnFactory();
try {
// 3. 启动adminServer
// 可以查看当前服务端节点的一些信息
adminServer.start();
} catch (AdminServerException e) {
LOG.warn("Problem starting AdminServer", e);
System.out.println(e);
}
// 4. 开始leader选举
startLeaderElection();
// 5. 开始主循环，不同的角色执行不同的操作
super.start();
}
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