根据官方文档修炼Kafka神器，详细内容请戳这里。本文简要介绍Kafka特性和优势，以及在实战当中遇到的两个问题及解决方式。本文为Kafka系列文章，请关注后续更新。
Kafka版本：2.12-0.10.2.0
操作系统：CentOS 6.5
Kafka的三个特性：
（1）可以发布和订阅Records流，相当于一个消息队列或者消息系统；
（2）可以存储Records流，并且具有容错性；
（3）可以对Records流进行处理。
Kafka的两个优势：
（1）通过建立实时的流数据管道，可靠的在系统间或应用间获取数据；
（2）通过建立实时的流应用，转换成或者反应成数据流。
问题1：Kafka的Source和Binary：
在使用官方教程学习当中，进行到Step 2时，运行如下命令，出现找不到main class的错误。
[root@localhost kafka-0.10.2.0-src]# ./bin/zookeeper-server-start.sh config/zookeeper.properties Error: Could not find or load main class org.apache.zookeeper.server.quorum.QuorumPeerMain
百思不得其解，考虑是否因为Linux自带JDK，于是卸载JDK，安装JDK1.8，问题依旧，开始Google求助，在StackOverflow官网找到解决方案，原因是下错了包。使用的是未经过编译的Source，下载Binary后一切恢复正常。
问题2：按照官方教程找不到server.properties进程：
问题1解决后，一切操作正常，直到运行到如下命令，没有显示相应的进程信息。
[root@localhost kafka_2.12-0.10.2.0]# ps aux | grep server1.properties root 28779 0.0 0.0 103252 876 pts/2 S+ 11:14 0:00 grep server1.properties
开始抓狂，怀疑是命令问题，于是开始研究ps命令，试了ps -ef依旧无果，使用jps命令发现三个Kafka进程运行正常，但无法和server1.properties对应起来。
[root@localhost kafka_2.12-0.10.2.0]# jps 22596 Kafka 23221 Kafka 25689 Jps 22909 Kafka 22318 QuorumPeerMain
想到可以利用PID查找对应的进程名，结果如下，三个Kafka进程之间无任何区别，依旧无法将PID和server1.properties对应。
[root@localhost kafka_2.12-0.10.2.0]# ps aux | grep 22596 root 22596 1.4 4.5 7892660 679216 pts/3 Sl 15:12 2:08 /home/jdk1.8.0_121/bin/java -Xmx1G -Xms1G -server -XX:+UseG1GC -XX:MaxGCPauseMillis=20 -XX:InitiatingHeapOccupancyPercent=35 -XX:+DisableExplicitGC -Djava.awt.headless=true -Xloggc:/home/kafka_2.12-0.10.2.0/bin/../logs/kafkaServer-gc.log -verbose:gc -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintGCTimeStamps -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Dkafka.logs.dir=/home/kafka_2.12-0.10.2.0/bin/../logs -Dlog4j.configuration=file:./bin/../config/log4j.properties -cp .:/home/jdk1.8.0_121/lib/dt.jar:/home/jdk1.8.0_121/lib/tools.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/aopalliance-repackaged-2.5.0-b05.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/argparse4j-0.7.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/connect-api-0.10.2.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/connect-file-0.10.2.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/connect-json-0.10.2.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/connect-runtime-0.10.2.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/connect-transforms-0.10.2.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/guava-18.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/hk2-api-2.5.0-b05.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/hk2-locator-2.5.0-b05.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/hk2-utils-2.5.0-b05.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jackson-annotations-2.8.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jackson-annotations-2.8.5.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jackson-core-2.8.5.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jackson-databind-2.8.5.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jackson-jaxrs-base-2.8.5.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jackson-jaxrs-json-provider-2.8.5.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jackson-module-jaxb-annotations-2.8.5.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/javassist-3.20.0-GA.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/javax.annotation-api-1.2.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/javax.inject-1.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/javax.inject-2.5.0-b05.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/javax.servlet-api-3.1.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/javax.ws.rs-api-2.0.1.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jersey-client-2.24.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jersey-common-2.24.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jersey-container-servlet-2.24.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jersey-container-servlet-core-2.24.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jersey-guava-2.24.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jersey-media-jaxb-2.24.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jersey-server-2.24.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jetty-continuation-9.2.15.v20160210.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jetty-http-9.2.15.v20160210.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jetty-io-9.2.15.v20160210.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jetty-security-9.2.15.v20160210.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jetty-server-9.2.15.v20160210.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jetty-servlet-9.2.15.v20160210.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jetty-servlets-9.2.15.v20160210.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jetty-util-9.2.15.v20160210.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jopt-simple-5.0.3.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/kafka_2.12-0.10.2.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/kafka_2.12-0.10.2.0-sources.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/kafka_2.12-0.10.2.0-test-sources.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/kafka-clients-0.10.2.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/kafka-log4j-appender-0.10.2.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/kafka-streams-0.10.2.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/kafka-streams-examples-0.10.2.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/kafka-tools-0.10.2.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/log4j-1.2.17.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/lz4-1.3.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/metrics-core-2.2.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/osgi-resource-locator-1.0.1.jar:/home/kafka_2.12-0.10.2.0/b root 25632 0.0 0.0 103252 832 pts/2 R+ 17:42 0:00 grep 22596
[root@localhost kafka_2.12-0.10.2.0]# ps aux | grep 22909 root 22909 0.9 5.5 6837340 821064 pts/3 Sl Feb28 11:48 /home/jdk1.8.0_121/bin/java -Xmx1G -Xms1G -server -XX:+UseG1GC -XX:MaxGCPauseMillis=20 -XX:InitiatingHeapOccupancyPercent=35 -XX:+DisableExplicitGC -Djava.awt.headless=true -Xloggc:/home/kafka_2.12-0.10.2.0/bin/../logs/kafkaServer-gc.log -verbose:gc -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintGCTimeStamps -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Dkafka.logs.dir=/home/kafka_2.12-0.10.2.0/bin/../logs -Dlog4j.configuration=file:./bin/../config/log4j.properties -cp .:/home/jdk1.8.0_121/lib/dt.jar:/home/jdk1.8.0_121/lib/tools.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/aopalliance-repackaged-2.5.0-b05.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/argparse4j-0.7.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/connect-api-0.10.2.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/connect-file-0.10.2.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/connect-json-0.10.2.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/connect-runtime-0.10.2.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/connect-transforms-0.10.2.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/guava-18.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/hk2-api-2.5.0-b05.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/hk2-locator-2.5.0-b05.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/hk2-utils-2.5.0-b05.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jackson-annotations-2.8.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jackson-annotations-2.8.5.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jackson-core-2.8.5.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jackson-databind-2.8.5.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jackson-jaxrs-base-2.8.5.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jackson-jaxrs-json-provider-2.8.5.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jackson-module-jaxb-annotations-2.8.5.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/javassist-3.20.0-GA.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/javax.annotation-api-1.2.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/javax.inject-1.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/javax.inject-2.5.0-b05.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/javax.servlet-api-3.1.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/javax.ws.rs-api-2.0.1.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jersey-client-2.24.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jersey-common-2.24.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jersey-container-servlet-2.24.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jersey-container-servlet-core-2.24.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jersey-guava-2.24.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jersey-media-jaxb-2.24.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jersey-server-2.24.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jetty-continuation-9.2.15.v20160210.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jetty-http-9.2.15.v20160210.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jetty-io-9.2.15.v20160210.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jetty-security-9.2.15.v20160210.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jetty-server-9.2.15.v20160210.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jetty-servlet-9.2.15.v20160210.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jetty-servlets-9.2.15.v20160210.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jetty-util-9.2.15.v20160210.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/jopt-simple-5.0.3.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/kafka_2.12-0.10.2.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/kafka_2.12-0.10.2.0-sources.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/kafka_2.12-0.10.2.0-test-sources.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/kafka-clients-0.10.2.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/kafka-log4j-appender-0.10.2.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/kafka-streams-0.10.2.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/kafka-streams-examples-0.10.2.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/kafka-tools-0.10.2.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/log4j-1.2.17.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/lz4-1.3.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/metrics-core-2.2.0.jar:/home/kafka_2.12-0.10.2.0/bin/../libs/osgi-resource-locator-1.0.1.jar:/home/kafka_2.12-0.10.2.0/b root 28818 0.0 0.0 103252 840 pts/2 R+ 11:22 0:00 grep 22909
思考之后，决定使用lsof命令，查询端口号和PID之间的对应关系，因为按照教程部署的Kafka三个节点都在本机上，以端口号区分，server1.properties的端口号设置的是9093。
[root@localhost kafka_2.12-0.10.2.0]# lsof -i:9093 COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME java 22909 root 102u IPv6 278744 0t0 TCP *:9093 (LISTEN) java 22909 root 103u IPv6 292045 0t0 TCP localhost:9093->localhost:49648 (ESTABLISHED) java 25991 root 84u IPv6 292044 0t0 TCP localhost:49648->localhost:9093 (ESTABLISHED)
问题解决，可以继续教程进行fault-tolerance测试了。
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