ZooKeeper - 四字命令解析

四字命令

操作方式

echo “ruok” | nc 192.168.0.106 2181

cons

输出当前服务器的所有客户端的连接信息

NIOServerCnxn代码：

 private class ConsCommand extends CommandThread {public ConsCommand(PrintWriter pw) {super(pw);}@SuppressWarnings("unchecked")@Overridepublic void commandRun() {if (zkServer == null) {pw.println(ZK_NOT_SERVING);} else {// clone should be faster than iteration// ie give up the cnxns lock fasterHashSet<NIOServerCnxn> cnxns;synchronized (factory.cnxns) {cnxns = (HashSet<NIOServerCnxn>) factory.cnxns.clone();}for (NIOServerCnxn c : cnxns) {c.dumpConnectionInfo(pw, false);pw.println();}pw.println();}}}

ServerCnxn代码：

protected synchronized voiddumpConnectionInfo(PrintWriter pwriter, boolean brief) {pwriter.print(" ");pwriter.print(getRemoteSocketAddress());pwriter.print("[");int interestOps = getInterestOps();pwriter.print(interestOps == 0 ? "0" : Integer.toHexString(interestOps));pwriter.print("](queued=");pwriter.print(getOutstandingRequests());pwriter.print(",recved=");pwriter.print(getPacketsReceived());pwriter.print(",sent=");pwriter.print(getPacketsSent());if (!brief) {long sessionId = getSessionId();if (sessionId != 0) {pwriter.print(",sid=0x");pwriter.print(Long.toHexString(sessionId));pwriter.print(",lop=");pwriter.print(getLastOperation());pwriter.print(",est=");pwriter.print(getEstablished().getTime());pwriter.print(",to=");pwriter.print(getSessionTimeout());long lastCxid = getLastCxid();if (lastCxid >= 0) {pwriter.print(",lcxid=0x");pwriter.print(Long.toHexString(lastCxid));}pwriter.print(",lzxid=0x");pwriter.print(Long.toHexString(getLastZxid()));pwriter.print(",lresp=");pwriter.print(getLastResponseTime());pwriter.print(",llat=");pwriter.print(getLastLatency());pwriter.print(",minlat=");pwriter.print(getMinLatency());pwriter.print(",avglat=");pwriter.print(getAvgLatency());pwriter.print(",maxlat=");pwriter.print(getMaxLatency());}}pwriter.print(")");}

stat、srvr

输出ZooKeeper版本号、只读模式的判断、服务器状态信息、节点数量

stat额外输出当前服务器的所有客户端的连接信息。

 private class StatCommand extends CommandThread {int len;public StatCommand(PrintWriter pw, int len) {super(pw);this.len = len;}@SuppressWarnings("unchecked")@Overridepublic void commandRun() {if (zkServer == null) {pw.println(ZK_NOT_SERVING);}else {   pw.print("Zookeeper version: ");pw.println(Version.getFullVersion());if (zkServer instanceof ReadOnlyZooKeeperServer) {pw.println("READ-ONLY mode; serving only " +"read-only clients");}if (len == statCmd) {LOG.info("Stat command output");pw.println("Clients:");// clone should be faster than iteration// ie give up the cnxns lock fasterHashSet<NIOServerCnxn> cnxnset;synchronized(factory.cnxns){cnxnset = (HashSet<NIOServerCnxn>)factory.cnxns.clone();}for(NIOServerCnxn c : cnxnset){c.dumpConnectionInfo(pw, true);pw.println();}pw.println();}pw.print(zkServer.serverStats().toString());pw.print("Node count: ");pw.println(zkServer.getZKDatabase().getNodeCount());}}}

dump

输出当前集群的所有会话信息，以及创建的临时节点信息。

 private class DumpCommand extends CommandThread {public DumpCommand(PrintWriter pw) {super(pw);}@Overridepublic void commandRun() {if (zkServer == null) {pw.println(ZK_NOT_SERVING);}else {pw.println("SessionTracker dump:");zkServer.sessionTracker.dumpSessions(pw);pw.println("ephemeral nodes dump:");zkServer.dumpEphemerals(pw);}}}

crst

重置所有客户端的连接状态信息。

 private class CnxnStatResetCommand extends CommandThread {public CnxnStatResetCommand(PrintWriter pw) {super(pw);}@Overridepublic void commandRun() {if (zkServer == null) {pw.println(ZK_NOT_SERVING);} else {synchronized(factory.cnxns){for(ServerCnxn c : factory.cnxns){c.resetStats();}}pw.println("Connection stats reset.");}}}

srst

重置当前服务器的状态信息

 private class StatResetCommand extends CommandThread {public StatResetCommand(PrintWriter pw) {super(pw);}@Overridepublic void commandRun() {if (zkServer == null) {pw.println(ZK_NOT_SERVING);}else { zkServer.serverStats().reset();pw.println("Server stats reset.");}}}

conf

输出当前服务器的配置信息

 private class ConfCommand extends CommandThread {ConfCommand(PrintWriter pw) {super(pw);}@Overridepublic void commandRun() {if (zkServer == null) {pw.println(ZK_NOT_SERVING);} else {zkServer.dumpConf(pw);}}}

envi

输出当前服务器的运行时的环境信息

 private class EnvCommand extends CommandThread {EnvCommand(PrintWriter pw) {super(pw);}@Overridepublic void commandRun() {List<Environment.Entry> env = Environment.list();pw.println("Environment:");for(Environment.Entry e : env) {pw.print(e.getKey());pw.print("=");pw.println(e.getValue());}} }

stmk

设置跟踪掩码

 private class SetTraceMaskCommand extends CommandThread {long trace = 0;SetTraceMaskCommand(PrintWriter pw, long trace) {super(pw);this.trace = trace;}@Overridepublic void commandRun() {pw.print(trace);}}

gtmk

获取跟踪掩码

 private class TraceMaskCommand extends CommandThread {TraceMaskCommand(PrintWriter pw) {super(pw);}@Overridepublic void commandRun() {long traceMask = ZooTrace.getTextTraceLevel();pw.print(traceMask);}}

 private static long traceMask = CLIENT_REQUEST_TRACE_MASK| SERVER_PACKET_TRACE_MASK | SESSION_TRACE_MASK| WARNING_TRACE_MASK;public static long getTextTraceLevel() {return traceMask;}

ruok

检测当前服务器是否正在运行

 private class RuokCommand extends CommandThread {public RuokCommand(PrintWriter pw) {super(pw);}@Overridepublic void commandRun() {pw.print("imok");}}

wchs、wchc、wchp

wchs：输出当前服务器的watcher的概要信息。

wchc：输出当前服务器的watcher的详细信息，以会话为单位归组。

wchp：输出当前服务器的watcher的详细信息，以路径为单位归组。

 private class WatchCommand extends CommandThread {int len = 0;public WatchCommand(PrintWriter pw, int len) {super(pw);this.len = len;}@Overridepublic void commandRun() {if (zkServer == null) {pw.println(ZK_NOT_SERVING);} else {DataTree dt = zkServer.getZKDatabase().getDataTree();if (len == wchsCmd) {dt.dumpWatchesSummary(pw);} else if (len == wchpCmd) {dt.dumpWatches(pw, true);} else {dt.dumpWatches(pw, false);}pw.println();}}}

isro

输出当前服务器的模式 - ro (只读) / rw (可读写)

 private class IsroCommand extends CommandThread {public IsroCommand(PrintWriter pw) {super(pw);}@Overridepublic void commandRun() {if (zkServer == null) {pw.print("null");} else if (zkServer instanceof ReadOnlyZooKeeperServer) {pw.print("ro");} else {pw.print("rw");}}}

mntr

输出比stat命令更详尽的服务器状态信息，包括请求处理的延迟情况、服务器内存数据库的大小、集群数据的同步情况等。

 private class MonitorCommand extends CommandThread {MonitorCommand(PrintWriter pw) {super(pw);}@Overridepublic void commandRun() {if(zkServer == null) {pw.println(ZK_NOT_SERVING);return;}ZKDatabase zkdb = zkServer.getZKDatabase();ServerStats stats = zkServer.serverStats();print("version", Version.getFullVersion());print("avg_latency", stats.getAvgLatency());print("max_latency", stats.getMaxLatency());print("min_latency", stats.getMinLatency());print("packets_received", stats.getPacketsReceived());print("packets_sent", stats.getPacketsSent());print("num_alive_connections", stats.getNumAliveClientConnections());print("outstanding_requests", stats.getOutstandingRequests());print("server_state", stats.getServerState());print("znode_count", zkdb.getNodeCount());print("watch_count", zkdb.getDataTree().getWatchCount());print("ephemerals_count", zkdb.getDataTree().getEphemeralsCount());print("approximate_data_size", zkdb.getDataTree().approximateDataSize());OSMXBean osMbean = new OSMXBean();if (osMbean != null && osMbean.getUnix() == true) {print("open_file_descriptor_count", osMbean.getOpenFileDescriptorCount());print("max_file_descriptor_count", osMbean.getMaxFileDescriptorCount());}if(stats.getServerState().equals("leader")) {Leader leader = ((LeaderZooKeeperServer)zkServer).getLeader();print("followers", leader.getLearners().size());print("synced_followers", leader.getForwardingFollowers().size());print("pending_syncs", leader.getNumPendingSyncs());}}private void print(String key, long number) {print(key, "" + number);}private void print(String key, String value) {pw.print("zk_");pw.print(key);pw.print("\t");pw.println(value);}}

完整源代码

对于四字命令的检查处理。

 /** Return if four letter word found and responded to, otw false **/private boolean checkFourLetterWord(final SelectionKey k, final int len)throws IOException{// We take advantage of the limited size of the length to look// for cmds. They are all 4-bytes which fits inside of an intString cmd = cmd2String.get(len);if (cmd == null) {return false;}LOG.info("Processing " + cmd + " command from "+ sock.socket().getRemoteSocketAddress());packetReceived();/** cancel the selection key to remove the socket handling* from selector. This is to prevent netcat problem wherein* netcat immediately closes the sending side after sending the* commands and still keeps the receiving channel open. * The idea is to remove the selectionkey from the selector* so that the selector does not notice the closed read on the* socket channel and keep the socket alive to write the data to* and makes sure to close the socket after its done writing the data*/if (k != null) {try {k.cancel();} catch(Exception e) {LOG.error("Error cancelling command selection key ", e);}}final PrintWriter pwriter = new PrintWriter(new BufferedWriter(new SendBufferWriter()));if (len == ruokCmd) {RuokCommand ruok = new RuokCommand(pwriter);ruok.start();return true;} else if (len == getTraceMaskCmd) {TraceMaskCommand tmask = new TraceMaskCommand(pwriter);tmask.start();return true;} else if (len == setTraceMaskCmd) {incomingBuffer = ByteBuffer.allocate(8);int rc = sock.read(incomingBuffer);if (rc < 0) {throw new IOException("Read error");}incomingBuffer.flip();long traceMask = incomingBuffer.getLong();ZooTrace.setTextTraceLevel(traceMask);SetTraceMaskCommand setMask = new SetTraceMaskCommand(pwriter, traceMask);setMask.start();return true;} else if (len == enviCmd) {EnvCommand env = new EnvCommand(pwriter);env.start();return true;} else if (len == confCmd) {ConfCommand ccmd = new ConfCommand(pwriter);ccmd.start();return true;} else if (len == srstCmd) {StatResetCommand strst = new StatResetCommand(pwriter);strst.start();return true;} else if (len == crstCmd) {CnxnStatResetCommand crst = new CnxnStatResetCommand(pwriter);crst.start();return true;} else if (len == dumpCmd) {DumpCommand dump = new DumpCommand(pwriter);dump.start();return true;} else if (len == statCmd || len == srvrCmd) {StatCommand stat = new StatCommand(pwriter, len);stat.start();return true;} else if (len == consCmd) {ConsCommand cons = new ConsCommand(pwriter);cons.start();return true;} else if (len == wchpCmd || len == wchcCmd || len == wchsCmd) {WatchCommand wcmd = new WatchCommand(pwriter, len);wcmd.start();return true;} else if (len == mntrCmd) {MonitorCommand mntr = new MonitorCommand(pwriter);mntr.start();return true;} else if (len == isroCmd) {IsroCommand isro = new IsroCommand(pwriter);isro.start();return true;}return false;}

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