RocketMQ笔记：Namesrv

Namesrv简介

Broker启动时，会向所有的Nameserver注册。

消息生产者发送消息前，先去Nameserver拉取broker服务器地址列表。然后根据负载均衡算法选择一台Broker进行消息发送。

NameServer与Broker保持长连接，并每隔30s检测Broker是否存活。

如果检测到Broker宕机，则从路由列表中将其移除。但不会马上通知消息生产者。而是在消息发送端提供容错机制来保证消息发送的高可用性。

NameServer集群之间并不互相通信，路由信息并非是强一致性。

NameServer启动流程

加载配置文件

// NamesrvConfig
final NamesrvConfig namesrvConfig = new NamesrvConfig();
// NettyServerConfig
final NettyServerConfig nettyServerConfig = new NettyServerConfig();
nettyServerConfig.setListenPort(9876);
if (commandLine.hasOption('c')) {
    String file = commandLine.getOptionValue('c');
    if (file != null) {
        InputStream in = new BufferedInputStream(new FileInputStream(file));
        properties = new Properties();
        properties.load(in);
        MixAll.properties2Object(properties, namesrvConfig);
        MixAll.properties2Object(properties, nettyServerConfig);
        namesrvConfig.setConfigStorePath(file);
        System.out.printf("load config properties file OK, %s%n", file);
        in.close();
    }
}

NameServerConfig的配置来源有两个：

通过-c指定配置文件路径
使用-- 属性名属性值来设置，如 --listenPort 9876

NamesrvConfig

public class NamesrvConfig {
    private String rocketmqHome = System.getProperty(MixAll.ROCKETMQ_HOME_PROPERTY, System.getenv(MixAll.ROCKETMQ_HOME_ENV));
    private String kvConfigPath = System.getProperty("user.home") + File.separator + "namesrv" + File.separator + "kvConfig.json";
    private String configStorePath = System.getProperty("user.home") + File.separator + "namesrv" + File.separator + "namesrv.properties";
    private String productEnvName = "center";
    private boolean clusterTest = false;
    private boolean orderMessageEnable = false;
}

rocketmqHome：rocketmq主目录，配置环境变量
kvConfigPath：存储KV配置的默认路径
configStorePath：nameserver默认配置文件路径
orderMessageEnable：是否支持顺序消息

NettyServerConfig

public class NettyServerConfig implements Cloneable {
    private int listenPort = 8888;
    private int serverWorkerThreads = 8;
    private int serverCallbackExecutorThreads = 0;
    private int serverSelectorThreads = 3;
    private int serverOnewaySemaphoreValue = 256;
    private int serverAsyncSemaphoreValue = 64;
    private int serverChannelMaxIdleTimeSeconds = 120;

    private int serverSocketSndBufSize = NettySystemConfig.socketSndbufSize;
    private int serverSocketRcvBufSize = NettySystemConfig.socketRcvbufSize;
    private boolean serverPooledByteBufAllocatorEnable = true;
    private boolean useEpollNativeSelector = false;
}

listenPort：监听端口
serverWorkerThread：Netty业务线程池线程个数
serverCallbackExecutorThreads：Netty公共的线程池线程个数。如果业务类型没有指定线程池，则由public线程池执行
serverSelectorThreads：IO线程池线程个数。用于解析请求，然后将任务转发给对应的业务类型，再将结果返回给调用方。
serverOnewaySemaphoreValue：send oneway消息请求并发度（Broker）
serverAsyncSemaphoreValue：异步消息发送的最大并发度（Broker）
serverChannelMaxIdleTimeSeconds：网络连接的最大空闲时间，如果连接空闲时间操作此数，连接将被关闭
serverSocketSndBufSize：网络socket发送缓存区大小，默认64k
serverSocketRcvBufSize：网络socket接收缓存区大小，默认64k
serverPooledByteBufAllocatorEnable：ByteBuffer是否开启缓存
useEpollNativeSelector：是否启用Epoll IO模型，Linux建议开启

根据启动属性创建NamesrvController，并初始化改实例。

public boolean initialize() {
	// 加载KV配置
    this.kvConfigManager.load();
	// 创建NameServer网络处理对象
    this.remotingServer = new NettyRemotingServer(this.nettyServerConfig, this.brokerHousekeepingService);

    this.remotingExecutor =
        Executors.newFixedThreadPool(nettyServerConfig.getServerWorkerThreads(), new ThreadFactoryImpl("RemotingExecutorThread_"));

    this.registerProcessor();
	// 每隔10s扫描一次Broker，移除不激活的Broker
    this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {

        @Override
        public void run() {
            NamesrvController.this.routeInfoManager.scanNotActiveBroker();
        }
    }, 5, 10, TimeUnit.SECONDS);

    // 每10分钟打印一次KV配置
    this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {

        @Override
        public void run() {
            NamesrvController.this.kvConfigManager.printAllPeriodically();
        }
    }, 1, 10, TimeUnit.MINUTES);
	// 省略部分代码
    return true;
}

注册钩子函数

// 注册钩子函数
Runtime.getRuntime().addShutdownHook(new ShutdownHookThread(log, new Callable<Void>() {
    @Override
    public Void call() throws Exception {
        // 关闭线程池，释放资源
        controller.shutdown();
        return null;
    }
}));

路由注册和故障剔除

NameServer的主要作用是为消息生产者和消息消费者提供Topic的路由信息。那么NameServer需要存储路由的基本信息。包括路由注册和剔除故障的broker

路由元信息

org.apache.rocketmq.namesrv.routeinfo.RouteInfoManager

public class RouteInfoManager {
   	// Topic消息队列路由信息，消息发送时根据路由信息进行负债均衡
    private final HashMap<String/* topic */, List<QueueData>> topicQueueTable;
    
    // Broker基础信息，包含brokerName、所属集群名称、主备Broker地址
    private final HashMap<String/* brokerName */, BrokerData> brokerAddrTable;
    
    // Broker 集群信息，存储集群中所有Broker的名称
    private final HashMap<String/* clusterName */, Set<String/* brokerName */>> clusterAddrTable;
    
    // Broker状态信息，Namesrv收到信息包后替换该信息
    private final HashMap<String/* brokerAddr */, BrokerLiveInfo> brokerLiveTable;
    
    // Broker上的FilterServer列表，用于类模式消息过滤
    private final HashMap<String/* brokerAddr */, List<String>/* Filter Server */> filterServerTable;
}

路由注册

路由注册是通过NameServer和Broker的心跳包功能实现的。

Broker启动时向集群中所有的NameServer发送心跳语句。

每隔 30s 向集群中所有 NameServer发送心跳包，NameServer收到心跳包后，更新 BrokerLiveInfo的lastUpdatestamp。

NameServer每隔 10s 扫描一次brokerLiveTable，如果一个Broker连续120s没有发送心跳包，将会被NameServer移除路由信息，同时关闭Socket。

Broker发送心跳包

org.apache.rocketmq.broker.BrokerController#start中的代码片段：

this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {

    @Override
    public void run() {
        try {
            // 发送心跳包
            BrokerController.this.registerBrokerAll(true, false, brokerConfig.isForceRegister());
        } catch (Throwable e) {
            log.error("registerBrokerAll Exception", e);
        }
    }
}, 1000 * 10, Math.max(10000, Math.min(brokerConfig.getRegisterNameServerPeriod(), 60000)), TimeUnit.MILLISECONDS);

public List<RegisterBrokerResult> registerBrokerAll(
    final String clusterName,
    final String brokerAddr,
    final String brokerName,
    final long brokerId,
    final String haServerAddr,
    final TopicConfigSerializeWrapper topicConfigWrapper,
    final List<String> filterServerList,
    final boolean oneway,
    final int timeoutMills,
    final boolean compressed) {

    final List<RegisterBrokerResult> registerBrokerResultList = Lists.newArrayList();
    List<String> nameServerAddressList = this.remotingClient.getNameServerAddressList();
    if (nameServerAddressList != null && nameServerAddressList.size() > 0) {

        final RegisterBrokerRequestHeader requestHeader = new RegisterBrokerRequestHeader();
        // 省略设置requestHeader代码

        RegisterBrokerBody requestBody = new RegisterBrokerBody();
        // 省略处理body代码
        requestHeader.setBodyCrc32(bodyCrc32);
        final CountDownLatch countDownLatch = new CountDownLatch(nameServerAddressList.size());
        for (final String namesrvAddr : nameServerAddressList) {
            brokerOuterExecutor.execute(new Runnable() {
                @Override
                public void run() {
                    try {
                        RegisterBrokerResult result = registerBroker(namesrvAddr,oneway, timeoutMills,requestHeader,body);
                        if (result != null) {
                            registerBrokerResultList.add(result);
                        }

                        log.info("register broker[{}]to name server {} OK", brokerId, namesrvAddr);
                    } catch (Exception e) {
                        log.warn("registerBroker Exception, {}", namesrvAddr, e);
                    } finally {
                        countDownLatch.countDown();
                    }
                }
            });
        }

        try {
            countDownLatch.await(timeoutMills, TimeUnit.MILLISECONDS);
        } catch (InterruptedException e) {
        }
    }

    return registerBrokerResultList;
}

遍历NameServerList，依次发送心跳包。

NameServer处理心跳包

请求到达org.apache.rocketmq.namesrv.processor.DefaultRequestProcessor#processRequest，通过请求的RequestCode类型分发。

心跳包的请求类型为RequestCode.REGISTER_BROKER，根据版本调用registerBrokerWithFilterServer或者registerBroker，这两个方法都会调用org.apache.rocketmq.namesrv.routeinfo.RouteInfoManager#registerBroker。

RegisterBrokerResult result = this.namesrvController.getRouteInfoManager().registerBroker(
    // 集群名称
    requestHeader.getClusterName(),
    // Broker地址
    requestHeader.getBrokerAddr(),
    requestHeader.getBrokerName(),
    requestHeader.getBrokerId(),
    // master地址
    requestHeader.getHaServerAddr(),
    // 主题配置
    topicConfigWrapper,
    null,
    ctx.channel()
);

如果broker所属集群不存在，则新建并加入到clusterAddrTable

// 加锁，防止并发修改路由表
this.lock.writeLock().lockInterruptibly();

Set<String> brokerNames = this.clusterAddrTable.get(clusterName);
if (null == brokerNames) {
    // 如果broker所属集群不存在，则新建
    brokerNames = new HashSet<String>();
    // 并加入到集合中
    this.clusterAddrTable.put(clusterName, brokerNames);
}
brokerNames.add(brokerName);

如果brokerAddrTable不包含brokerName对应的brokerData，则新建brokerData并加入到集合中

boolean registerFirst = false;

BrokerData brokerData = this.brokerAddrTable.get(brokerName);
if (null == brokerData) {
    // 如果是初次注册，则新建并加入到集合中
    registerFirst = true;
    brokerData = new BrokerData(clusterName, brokerName, new HashMap<Long, String>());
    this.brokerAddrTable.put(brokerName, brokerData);
}
Map<Long, String> brokerAddrsMap = brokerData.getBrokerAddrs();
//Switch slave to master: first remove <1, IP:PORT> in namesrv, then add <0, IP:PORT>
//The same IP:PORT must only have one record in brokerAddrTable
Iterator<Entry<Long, String>> it = brokerAddrsMap.entrySet().iterator();
while (it.hasNext()) {
    Entry<Long, String> item = it.next();
    if (null != brokerAddr && brokerAddr.equals(item.getValue()) && brokerId != item.getKey()) {
        it.remove();
    }
}

String oldAddr = brokerData.getBrokerAddrs().put(brokerId, brokerAddr);
registerFirst = registerFirst || (null == oldAddr);

如果broker是Master，并且是初次注册，则需要创建或更新Topic路由元数据

if (null != topicConfigWrapper
    && MixAll.MASTER_ID == brokerId) {
    if (this.isBrokerTopicConfigChanged(brokerAddr, topicConfigWrapper.getDataVersion())
        || registerFirst) {
        ConcurrentMap<String, TopicConfig> tcTable =
            topicConfigWrapper.getTopicConfigTable();
        if (tcTable != null) {
            for (Map.Entry<String, TopicConfig> entry : tcTable.entrySet()) {
                this.createAndUpdateQueueData(brokerName, entry.getValue());
            }
        }
    }
}

根据topicConfig创建QueueData，然后更新topicUpdateTable。

private void createAndUpdateQueueData(final String brokerName, final TopicConfig topicConfig) {
    QueueData queueData = new QueueData();
    queueData.setBrokerName(brokerName);
    queueData.setWriteQueueNums(topicConfig.getWriteQueueNums());
    queueData.setReadQueueNums(topicConfig.getReadQueueNums());
    queueData.setPerm(topicConfig.getPerm());
    queueData.setTopicSynFlag(topicConfig.getTopicSysFlag());

    List<QueueData> queueDataList = this.topicQueueTable.get(topicConfig.getTopicName());
    if (null == queueDataList) {
        queueDataList = new LinkedList<QueueData>();
        queueDataList.add(queueData);
        this.topicQueueTable.put(topicConfig.getTopicName(), queueDataList);
        log.info("new topic registered, {} {}", topicConfig.getTopicName(), queueData);
    } else {
        boolean addNewOne = true;

        Iterator<QueueData> it = queueDataList.iterator();
        while (it.hasNext()) {
            QueueData qd = it.next();
            if (qd.getBrokerName().equals(brokerName)) {
                if (qd.equals(queueData)) {
                    addNewOne = false;
                } else {
                    log.info("topic changed, {} OLD: {} NEW: {}", topicConfig.getTopicName(), qd,
                        queueData);
                    it.remove();
                }
            }
        }

        if (addNewOne) {
            queueDataList.add(queueData);
        }
    }
}

更新BrokerInfo，BrokerInfo中包含上次更新时间，是剔除无效Broker的重要依据。

BrokerLiveInfo prevBrokerLiveInfo = this.brokerLiveTable.put(brokerAddr,
    new BrokerLiveInfo(
        System.currentTimeMillis(),
        topicConfigWrapper.getDataVersion(),
        channel,
        haServerAddr));
if (null == prevBrokerLiveInfo) {
    log.info("new broker registered, {} HAServer: {}", brokerAddr, haServerAddr);
}

if (filterServerList != null) {
    if (filterServerList.isEmpty()) {
        this.filterServerTable.remove(brokerAddr);
    } else {
        this.filterServerTable.put(brokerAddr, filterServerList);
    }
}

if (MixAll.MASTER_ID != brokerId) {
    String masterAddr = brokerData.getBrokerAddrs().get(MixAll.MASTER_ID);
    if (masterAddr != null) {
        BrokerLiveInfo brokerLiveInfo = this.brokerLiveTable.get(masterAddr);
        if (brokerLiveInfo != null) {
            result.setHaServerAddr(brokerLiveInfo.getHaServerAddr());
            result.setMasterAddr(masterAddr);
        }
    }
}

TopicQueueTable：Topic消息队列路由信息

BrokerAddrTable：Broker基础信息，包括brokerName、集群名称、主备Broker地址

ClusterAddrTable：Broker集群信息，存储集群中所有Broker名称

BrokerLiveTable：存储brokerLiveInfo，是剔除无效broker的关键数据

FilterServerTable：Broker上的FilterServer列表

路由剔除

路由剔除有两个触发点：

NameServer扫描发现上次更新的时间与当前时间差大于120s
Broker在正常关闭的情况下，会执行unRegisterBroker

public void scanNotActiveBroker() {
    Iterator<Entry<String, BrokerLiveInfo>> it = this.brokerLiveTable.entrySet().iterator();
    while (it.hasNext()) {
        Entry<String, BrokerLiveInfo> next = it.next();
        long last = next.getValue().getLastUpdateTimestamp();
        if ((last + BROKER_CHANNEL_EXPIRED_TIME) < System.currentTimeMillis()) {
            RemotingUtil.closeChannel(next.getValue().getChannel());
            it.remove();
            log.warn("The broker channel expired, {} {}ms", next.getKey(), BROKER_CHANNEL_EXPIRED_TIME);
            // 关闭通道
            this.onChannelDestroy(next.getKey(), next.getValue().getChannel());
        }
    }
}

找到要删除的broker。上写锁，从brokerLiveTable和filterServerTable删除broker。


Iterator<Entry<String, BrokerLiveInfo>> itBrokerLiveTable =
    this.brokerLiveTable.entrySet().iterator();
while (itBrokerLiveTable.hasNext()) {
    Entry<String, BrokerLiveInfo> entry = itBrokerLiveTable.next();
    if (entry.getValue().getChannel() == channel) {
        brokerAddrFound = entry.getKey();
        break;
    }
}

this.lock.writeLock().lockInterruptibly();
this.brokerLiveTable.remove(brokerAddrFound);
this.filterServerTable.remove(brokerAddrFound);

维护brokerAddrTable，遍历BrokerAddrTable，从brokerAddrs找到对应的broker，找到具体的Broker，并在brokerData中删除。如果brokerData不包含其他的brokerAddr，则从brokerAddrTable中删除。

while (itBrokerAddrTable.hasNext() && (null == brokerNameFound)) {
    BrokerData brokerData = itBrokerAddrTable.next().getValue();

    Iterator<Entry<Long, String>> it = brokerData.getBrokerAddrs().entrySet().iterator();
    while (it.hasNext()) {
        Entry<Long, String> entry = it.next();
        Long brokerId = entry.getKey();
        String brokerAddr = entry.getValue();
        if (brokerAddr.equals(brokerAddrFound)) {
            brokerNameFound = brokerData.getBrokerName();
            it.remove();
            log.info("remove brokerAddr[{}, {}] from brokerAddrTable, because channel destroyed",
                brokerId, brokerAddr);
            break;
        }
    }

    if (brokerData.getBrokerAddrs().isEmpty()) {
        removeBrokerName = true;
        itBrokerAddrTable.remove();
        log.info("remove brokerName[{}] from brokerAddrTable, because channel destroyed",
            brokerData.getBrokerName());
    }
}

根据brokerName，从clusterAddrTable中找到Broker并移除。如果移除后，brokerNames为空，那么从将该集群从clusterAddrTable中删除。

if (brokerNameFound != null && removeBrokerName) {
    Iterator<Entry<String, Set<String>>> it = this.clusterAddrTable.entrySet().iterator();
    while (it.hasNext()) {
        Entry<String, Set<String>> entry = it.next();
        String clusterName = entry.getKey();
        Set<String> brokerNames = entry.getValue();
        boolean removed = brokerNames.remove(brokerNameFound);
        if (removed) {
            log.info("remove brokerName[{}], clusterName[{}] from clusterAddrTable, because channel destroyed",
                brokerNameFound, clusterName);

            if (brokerNames.isEmpty()) {
                log.info("remove the clusterName[{}] from clusterAddrTable, because channel destroyed and no broker in this cluster",
                    clusterName);
                it.remove();
            }

            break;
        }
    }
}

删除topicQueueTable中的对应的queueData数据，如果该路由表为空，则删除。

if (removeBrokerName) {
    Iterator<Entry<String, List<QueueData>>> itTopicQueueTable =
        this.topicQueueTable.entrySet().iterator();
    while (itTopicQueueTable.hasNext()) {
        Entry<String, List<QueueData>> entry = itTopicQueueTable.next();
        String topic = entry.getKey();
        List<QueueData> queueDataList = entry.getValue();

        Iterator<QueueData> itQueueData = queueDataList.iterator();
        while (itQueueData.hasNext()) {
            QueueData queueData = itQueueData.next();
            if (queueData.getBrokerName().equals(brokerNameFound)) {
                itQueueData.remove();
                log.info("remove topic[{} {}], from topicQueueTable, because channel destroyed",
                    topic, queueData);
            }
        }

        if (queueDataList.isEmpty()) {
            itTopicQueueTable.remove();
            log.info("remove topic[{}] all queue, from topicQueueTable, because channel destroyed",
                topic);
        }
    }
}

释放锁

finally {
    this.lock.writeLock().unlock();
}

路由发现

RocketMQ的路由信息不是实时的，是有消息生产者从NameServer拉取路由信息。拉取路由信息的编码为RequestCode.GET_ROUTEINTO_BY_TOPIC。

org.apache.rocketmq.namesrv.processor.DefaultRequestProcessor#getRouteInfoByTopic:

public RemotingCommand getRouteInfoByTopic(ChannelHandlerContext ctx,
    RemotingCommand request) throws RemotingCommandException {
    final RemotingCommand response = RemotingCommand.createResponseCommand(null);
    final GetRouteInfoRequestHeader requestHeader =
        (GetRouteInfoRequestHeader) request.decodeCommandCustomHeader(GetRouteInfoRequestHeader.class);

    TopicRouteData topicRouteData = this.namesrvController.getRouteInfoManager().pickupTopicRouteData(requestHeader.getTopic());

    if (topicRouteData != null) {
        if (this.namesrvController.getNamesrvConfig().isOrderMessageEnable()) {
            String orderTopicConf =
                this.namesrvController.getKvConfigManager().getKVConfig(NamesrvUtil.NAMESPACE_ORDER_TOPIC_CONFIG,
                    requestHeader.getTopic());
            topicRouteData.setOrderTopicConf(orderTopicConf);
        }

        byte[] content = topicRouteData.encode();
        response.setBody(content);
        response.setCode(ResponseCode.SUCCESS);
        response.setRemark(null);
        return response;
    }

    response.setCode(ResponseCode.TOPIC_NOT_EXIST);
    response.setRemark("No topic route info in name server for the topic: " + requestHeader.getTopic()
        + FAQUrl.suggestTodo(FAQUrl.APPLY_TOPIC_URL));
    return response;
}

通过RouteInfoManager获取topicRouteData，如果topicRouteData存在，并且是OrderMessageEnable的，则从KvConfigManager获取KVConfig中的NAMESPACE_ORDER_TOPIC_CONFIG值，并填充到topicRouteData的OrderTopicConf中。

原文链接：https://blog.csdn.net/qq_33423418/article/details/107365773

RocketMQ笔记：Namesrv

Namesrv简介

NameServer启动流程

路由注册和故障剔除

路由元信息

路由注册

路由剔除

路由发现

标签云

近期文章

分类

RocketMQ笔记：Namesrv

Namesrv简介

NameServer启动流程

路由注册和故障剔除

路由元信息

路由注册

路由剔除

路由发现

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