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 和 PID 未找到）但是从日志中我们可以看到端口正在使用中
因此我们尝试执行以下操作，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 不包括杀戮标志
什么是正确关闭端口或释放 rhel 机器上的端口的选项？
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 )
一个开放的网络套接字就像一个文件句柄：一旦持有该句柄的程序退出，该套接字肯定是关闭的。所以我建议以下（以root身份执行）：
ss -tulpn | grep ":50070"查看结果（如果有的话），看起来与此类似：
如果您发现一个程序保持端口打开，请使用 kill 命令将其杀死：
kill <pid>但是由于持有开放端口的程序是一个服务，我真的建议你考虑其他关闭端口的方法：
systemctl stop <service>- 停止服务，一旦它退出，打开的端口也消失了......