想买保时捷的运维李先生 求救求救求救求救

问题来源

kafka机器调到了64G的内存，还是报内存不足，后经排查是监控脚本telnet导致的，但是作为脚本的当事人不太能接受这个事实，然后自己一直找答案也没找出来，有以下几个问题在脑袋里一直没解决，也没啥思路。

待解决的问题

1）telnet kafka_ip 9092，为什么telnet kafka的端口，也会写入kafka？
2）telnet是发送了什么数据给kafka，有218762506 bytes这么大？
3）kafka的配置文件socket.request.max.bytes=104857600与内存设置参数-Xmx3G -Xms3G -XX:MaxDirectMemorySize=3G的关系是什么，怎么调优？
4）kafka会将与9092相关的数据都写入到topic吗？
5）telnet以Ctrl + C结束与按两下回车键结束的区别？

问题描述

1）使用telnet kafka_ip 9092监控kafka的端口是否存在，频率为30s
2）kafka里偶尔会报错（telnet ip port 按两下enter）

[2020-09-29 02:32:04,182] WARN [SocketServer brokerId=0] Unexpected error from /x.x.x.x; closing connection (org.apache.kafka.common.network.Selector)
org.apache.kafka.common.network.InvalidReceiveException: Invalid receive (size = 218762506 larger than 104857600)
at org.apache.kafka.common.network.NetworkReceive.readFrom(NetworkReceive.java:104)
at org.apache.kafka.common.network.KafkaChannel.receive(KafkaChannel.java:335)
at org.apache.kafka.common.network.KafkaChannel.read(KafkaChannel.java:296)
at org.apache.kafka.common.network.Selector.attemptRead(Selector.java:560)
at org.apache.kafka.common.network.Selector.pollSelectionKeys(Selector.java:496)
at org.apache.kafka.common.network.Selector.poll(Selector.java:425)
at kafka.network.Processor.poll(SocketServer.scala:678)
at kafka.network.Processor.run(SocketServer.scala:583)
at java.lang.Thread.run(Thread.java:748)

抓包数据：

02:45:51.826114 IP ip-172-X-X-X.xxxxxxx.compute.internal.38900 > ip-172-X-X-X.xxxxxxx.compute.internal.XmlIpcRegSvc: Flags [S], seq 1800606878, win 26883, options [mss 8961,sackOK,TS val 3743494567 ecr 0,nop,wscale 7], length 0
02:45:51.826238 IP ip-172-X-X-X.xxxxxxx.compute.internal.38900 > ip-172-X-X-X.xxxxxxx.compute.internal.XmlIpcRegSvc: Flags [.], ack 814657885, win 211, options [nop,nop,TS val 3743494567 ecr 1556371964], length 0
02:45:53.417857 IP ip-172-X-X-X.xxxxxxx.compute.internal.38900 > ip-172-X-X-X.xxxxxxx.compute.internal.XmlIpcRegSvc: Flags [P.], seq 0:2, ack 1, win 211, options [nop,nop,TS val 3743496159 ecr 1556371964], length 2
02:45:54.754650 IP ip-172-X-X-X.xxxxxxx.compute.internal.38900 > ip-172-X-X-X.xxxxxxx.compute.internal.XmlIpcRegSvc: Flags [P.], seq 2:4, ack 1, win 211, options [nop,nop,TS val 3743497495 ecr 1556373556], length 2
02:45:54.755762 IP ip-172-X-X-X.xxxxxxx.compute.internal.38900 > ip-172-X-X-X.xxxxxxx.compute.internal.XmlIpcRegSvc: Flags [F.], seq 4, ack 2, win 211, options [nop,nop,TS val 3743497497 ecr 1556374893], length 0

02:41:50.268763 IP ip-172-X-X-X.xxxxxxx.compute.internal.58708 > ip-172-X-X-X.xxxxxxx.compute.internal.XmlIpcRegSvc: Flags [S], seq 346111553, win 26883, options [mss 8961,sackOK,TS val 3743253009 ecr 0,nop,wscale 7], length 0
02:41:50.269183 IP ip-172-X-X-X.xxxxxxx.compute.internal.58708 > ip-172-X-X-X.xxxxxxx.compute.internal.XmlIpcRegSvc: Flags [.], ack 3586979315, win 211, options [nop,nop,TS val 3743253009 ecr 1556045408], length 0
02:41:58.695326 IP ip-172-X-X-X.xxxxxxx.compute.internal.58708 > ip-172-X-X-X.xxxxxxx.compute.internal.XmlIpcRegSvc: Flags [P.], seq 0:2, ack 1, win 211, options [nop,nop,TS val 3743261435 ecr 1556045408], length 2
02:42:01.342115 IP ip-172-X-X-X.xxxxxxx.compute.internal.58708 > ip-172-X-X-X.xxxxxxx.compute.internal.XmlIpcRegSvc: Flags [P.], seq 2:4, ack 1, win 211, options [nop,nop,TS val 3743264082 ecr 1556053834], length 2
02:42:01.343416 IP ip-172-X-X-X.xxxxxxx.compute.internal.58708 > ip-172-X-X-X.xxxxxxx.compute.internal.XmlIpcRegSvc: Flags [F.], seq 4, ack 2, win 211, options [nop,nop,TS val 3743264083 ecr 1556056481], length 0

2）kafka里偶尔会报错（telnet ip port 按Control C）

[2020-09-29 02:30:41,878] WARN [SocketServer brokerId=0] Unexpected error from /x.x.x.x; closing connection (org.apache.kafka.common.network.Selector)
org.apache.kafka.common.network.InvalidReceiveException: Invalid receive (size = -720899)
at org.apache.kafka.common.network.NetworkReceive.readFrom(NetworkReceive.java:102)
at org.apache.kafka.common.network.KafkaChannel.receive(KafkaChannel.java:335)
at org.apache.kafka.common.network.KafkaChannel.read(KafkaChannel.java:296)
at org.apache.kafka.common.network.Selector.attemptRead(Selector.java:560)
at org.apache.kafka.common.network.Selector.pollSelectionKeys(Selector.java:496)
at org.apache.kafka.common.network.Selector.poll(Selector.java:425)
at kafka.network.Processor.poll(SocketServer.scala:678)
at kafka.network.Processor.run(SocketServer.scala:583)
at java.lang.Thread.run(Thread.java:748)

抓包数据：

02:42:40.625070 IP ip-172-X-X-X.xxxxxxx.compute.internal.45020 > ip-172-X-X-X.xxxxxxx.compute.internal.XmlIpcRegSvc: Flags [S], seq 2552278719, win 26883, options [mss 8961,sackOK,TS val 3743303365 ecr 0,nop,wscale 7], length 0
02:42:40.625428 IP ip-172-X-X-X.xxxxxxx.compute.internal.45020 > ip-172-X-X-X.xxxxxxx.compute.internal.XmlIpcRegSvc: Flags [.], ack 428181904, win 211, options [nop,nop,TS val 3743303366 ecr 1556095764], length 0
02:42:42.682674 IP ip-172-X-X-X.xxxxxxx.compute.internal.45020 > ip-172-X-X-X.xxxxxxx.compute.internal.XmlIpcRegSvc: Flags [P.], seq 0:5, ack 1, win 211, options [nop,nop,TS val 3743305423 ecr 1556095764], length 5

02:46:51.833208 IP ip-172-X-X-X.xxxxxxx.compute.internal.55998 > ip-172-X-X-X.xxxxxxx.compute.internal.XmlIpcRegSvc: Flags [S], seq 676331509, win 26883, options [mss 8961,sackOK,TS val 3743554574 ecr 0,nop,wscale 7], length 0
02:46:51.833323 IP ip-172-X-X-X.xxxxxxx.compute.internal.55998 > ip-172-X-X-X.xxxxxxx.compute.internal.XmlIpcRegSvc: Flags [.], ack 4163492978, win 211, options [nop,nop,TS val 3743554574 ecr 1556431971], length 0
02:46:52.838892 IP ip-172-X-X-X.xxxxxxx.compute.internal.55998 > ip-172-X-X-X.xxxxxxx.compute.internal.XmlIpcRegSvc: Flags [P.], seq 0:5, ack 1, win 211, options [nop,nop,TS val 3743555580 ecr 1556431971], length 5