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有哪些选项可以正确关闭手动端口或在 rhel 机器上释放端口？

tag-icon • tag-icon networking redhat port socket netstat
有哪些选项可以正确关闭手动端口或在 rhel 机器上释放端口？

我们有 redhat 7.5 服务器

我们怀疑端口 50070 没有被服务正确关闭，（我们通过 netstat 检查，未找到 PID）但从日志中我们可以看到该端口正在使用中

因此我们尝试做以下事情，例如，

ss --kill state listening src :50070
ss: unrecognized option '--kill'
Usage: ss [ OPTIONS ]
       ss [ OPTIONS ] [ FILTER ]
   -h, --help          this message
   -V, --version       output version information
   -n, --numeric       don't resolve service names
   -r, --resolve       resolve host names
   -a, --all           display all sockets
   -l, --listening     display listening sockets
   -o, --options       show timer information
   -e, --extended      show detailed socket information
   -m, --memory        show socket memory usage
   -p, --processes     show process using socket
   -i, --info          show internal TCP information
   -s, --summary       show socket usage summary
   -b, --bpf           show bpf filter socket information
   -Z, --context       display process SELinux security contexts
   -z, --contexts      display process and socket SELinux security contexts
   -N, --net           switch to the specified network namespace name

   -4, --ipv4          display only IP version 4 sockets
   -6, --ipv6          display only IP version 6 sockets
   -0, --packet        display PACKET sockets
   -t, --tcp           display only TCP sockets
   -u, --udp           display only UDP sockets
   -d, --dccp          display only DCCP sockets
   -w, --raw           display only RAW sockets
   -x, --unix          display only Unix domain sockets
   -f, --family=FAMILY display sockets of type FAMILY

   -A, --query=QUERY, --socket=QUERY
       QUERY := {all|inet|tcp|udp|raw|unix|unix_dgram|unix_stream|unix_seqpacket|packet|netlink}[,QUERY]

但 ss 不包括 kill 标志

在 rhel 机器上，有哪些选项可以正确关闭端口或释放端口？

日志是：

2020-07-18 21:26:22,753 INFO  impl.MetricsSystemImpl (MetricsSystemImpl.java:shutdown(606)) - NameNode metrics system shutdown complete.
2020-07-18 21:26:22,753 ERROR namenode.NameNode (NameNode.java:main(1783)) - Failed to start namenode.
java.net.BindException: Port in use: linux.gg.com:50070
        at org.apache.hadoop.http.HttpServer2.constructBindException(HttpServer2.java:1001)
        at org.apache.hadoop.http.HttpServer2.bindForSinglePort(HttpServer2.java:1023)
        at org.apache.hadoop.http.HttpServer2.openListeners(HttpServer2.java:1080)
        at org.apache.hadoop.http.HttpServer2.start(HttpServer2.java:937)
        at org.apache.hadoop.hdfs.server.namenode.NameNodeHttpServer.start(NameNodeHttpServer.java:170)
        at org.apache.hadoop.hdfs.server.namenode.NameNode.startHttpServer(NameNode.java:942)
        at org.apache.hadoop.hdfs.server.namenode.NameNode.initialize(NameNode.java:755)
        at org.apache.hadoop.hdfs.server.namenode.NameNode.<init>(NameNode.java:1001)
        at org.apache.hadoop.hdfs.server.namenode.NameNode.<init>(NameNode.java:985)
        at org.apache.hadoop.hdfs.server.namenode.NameNode.createNameNode(NameNode.java:1710)
        at org.apache.hadoop.hdfs.server.namenode.NameNode.main(NameNode.java:1778)
Caused by: java.net.BindException: Address already in use
        at sun.nio.ch.Net.bind0(Native Method)
        at sun.nio.ch.Net.bind(Net.java:433)
        at sun.nio.ch.Net.bind(Net.java:425)
        at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:223)
        at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74)
        at org.mortbay.jetty.nio.SelectChannelConnector.open(SelectChannelConnector.java:216)
        at org.apache.hadoop.http.HttpServer2.bindListener(HttpServer2.java:988)
        at org.apache.hadoop.http.HttpServer2.bindForSinglePort(HttpServer2.java:1019)
        ... 9 more
2020-07-18 21:26:22,755 INFO  util.ExitUtil (ExitUtil.java:terminate(124)) - Exiting with status 1
2020-07-18 21:26:22,757 INFO  namenode.NameNode (LogAdapter.java:info(47)) - SHUTDOWN_MSG:
/************************************************************
SHUTDOWN_MSG: Shutting down NameNode at 
************************************************************/
[root@linux hdfs]#
[root@linux hdfs]#
[root@linux hdfs]# netstat -tulpn | grep 50070 ( no PID number is returned )

答案1

打开的网络套接字就像文件句柄：一旦持有句柄的程序退出，套接字就一定会关闭。因此我建议执行以下操作（以 root 身份执行）：

ss -tulpn | grep ":50070"

检查结果（如果有），结果与此类似：

Netid  State      Recv-Q Send-Q Local Address:Port               Peer Address:Port              
udp    UNCONN     0      0      0.0.0.0:68                 0.0.0.0:*                   users:(("dhclient",pid=1670,fd=6))
udp    UNCONN     0      0      127.0.0.1:323                0.0.0.0:*                   users:(("chronyd",pid=1540,fd=1))
udp    UNCONN     0      0         [::1]:323                [::]:*                   users:(("chronyd",pid=1540,fd=2))
tcp    LISTEN     0      128    0.0.0.0:22                 0.0.0.0:*                   users:(("sshd",pid=1583,fd=3))

如果发现某个程序占用了该端口，请使用 kill 命令将其终止：

kill <pid>

但由于持有开放端口的程序是一项服务，我真的建议您考虑关闭端口的其他方法：

  • systemctl stop <service>- 这将停止服务，并且一旦退出，开放的端口也会消失......
  • 修改服务配置以不打开相关端口
  • 使用防火墙拒绝访问该端口

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