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