Score:0

Server

Application cannot start, claiming "port is already in use", but it is not

user1700494

8/12/23, 1:00 PM

Application (apache storm) cannot start throwing the below exception

2022-04-12 04:56:13.997 o.a.s.d.u.UIServer main [ERROR] Exception in UlServer 
java.io.I0Exception: Failed to bind to 0.0.0.0/0.0.0.0:8888 
at org.eclipsejettyserver.ServerConnector.openAcceptChannel(ServerConnectorjava346) ~[jetty-server-9.4.14.v20181114jan9.4.14.v20181114] 
at org.eclipsejetty.server.ServerConnector.open(ServerConnectorjava:308) ~[jetty-server-9.4.14.v20181114.jar:9.4.14.v20181114] 
at org.eclipsejetty.server.AbstractNetworkConnector.doStart(AbstractNetworkConnectorjava:80) ~[jetty-server-9.4.14.v20181114jar:9.4.14.v20181114] 
at org.eclipsejetty.server.ServerConnector.doStart(ServerConnectorjava:236) ~[jetty-server-9.4.14.v20181114jar.9.4.14-v20181114] 
at org.eclipsejetty.util.component.AbstractUfeCycle.start(AbstractlifeCyclejava:68) ~[jetty-util-9.4.14.v20181114jan9.4.14.v20181114] 
at org.eclipsejetty.server.Server.doStart(Serverjava:394) ~[jetty-server-9.4.14.v20181114.jar9.4.14.v20181114) 
at org.eclipsejetty.util.component.AbstractLifeCycle.start(AbstractlifeCyclejava:68) ~[jetty-util-9.4.14.v20181114jar.9.4.14.v20181114] 
at org.apache.storm.daemon.ui.U1Server.main(U1Serverjaval 79) [storm-webapp-2.2.0jar:2.2.0] 
Caused by: java.net-BindException: Address already in use 
at sun.nio.ch.Net.bindO(Native Method) ~[?:?] 
at sumnio.ch.Net.bind(Netjava:455) ~[?:?] 
at sun.nio.ch.Netbind(Netjava:447) ~[?:?] 
at sun.nio.chServerSocketChannelImpl.bind(ServerSocketChannellmpljava:227) ~[?:?] 
at sumnio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptorjava:80) ~[?:?] 
at org.eclipsejetty.server.ServerConnector.openAcceptChannel(ServerConnectorjava:342) ~[jetty-server-9.4.14.v20181114jan9.4.14.v20181114] 
... 7 more

The port is free though, I used multiple tools (telnet, nc, netstat etc) to ensure this. Also the same behaviour was spotted on another server with another app, but JMV-based as well
OS: RHEL 7.9

Java: 11.0.12

0 + 0

linux

java

Gerald Schneider

8/12/23, 1:05 PM

`0.0.0.0/0.0.0.0:8888` is an unusual style for a listener. What exactly have you configured in your application?

Ben Voigt

8/12/23, 9:52 PM

The actual error is "failed to bind", any "port is already in use" message may be a well-meaning-but-wrong troubleshooting suggestion. Privileges/capabilities (such as SELinux uses) can also cause binding failure.

Jasen

8/13/23, 11:59 PM

Were you were able to successfuly listen on port 8888 using `nc`? or did you only try to connect to it?

Juraj Martinka

8/14/23, 4:37 AM

How exactly did you check that the port is "free"? Can you share the commands you run and their output? One possible problem you might be facing is a socket in TIME_WAIT state - see e.g. https://stackoverflow.com/questions/3757289/when-is-tcp-option-so-linger-0-required/13088864#13088864

Score:-1

Server

Petr Schönmann

8/12/23, 2:13 PM

Try check TCP and UDP listeners too

netstat -plantu | grep 8888

You can check ports which are opened with lsof too

lsof -i -P -n

Example output

root@machine:~# lsof -i -P -n
COMMAND     PID        USER   FD   TYPE  DEVICE SIZE/OFF NODE NAME
memcached   471    memcache   26u  IPv4   18741      0t0  TCP 127.0.0.1:11211 (LISTEN)
vsftpd      511        root    3u  IPv6   18621      0t0  TCP *:21 (LISTEN)
sshd        516        root    3u  IPv4   16971      0t0  TCP *:22 (LISTEN)
sshd        516        root    4u  IPv6   16980      0t0  TCP *:22 (LISTEN)
mysqld      831       mysql   21u  IPv6   20656      0t0  TCP *:33060 (LISTEN)
mysqld      831       mysql   26u  IPv4   17309      0t0  TCP *:3306 (LISTEN)
apache2   32378        root    4u  IPv6 4392606      0t0  TCP *:80 (LISTEN)
apache2   32378        root    6u  IPv6 4392610      0t0  TCP *:443 (LISTEN)
apache2   32396    www-data    4u  IPv6 4392606      0t0  TCP *:80 (LISTEN)
apache2   32396    www-data    6u  IPv6 4392610      0t0  TCP *:443 (LISTEN)
apache2   32397    www-data    4u  IPv6 4392606      0t0  TCP *:80 (LISTEN)
apache2   32397    www-data    6u  IPv6 4392610      0t0  TCP *:443 (LISTEN)

0 + 0

Gerald Schneider

8/12/23, 2:19 PM

This does not answer the question, it should be a comment. And the op states that this has already been checked.

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Application cannot start, claiming "port is already in use", but it is not

TH: แอปพลิเคชันไม่สามารถเริ่มทำงานได้ โดยอ้างว่า "พอร์ตถูกใช้งานแล้ว" แต่ไม่ใช่

RO: Aplicația nu poate porni, pretinzând că „portul este deja în uz”, dar nu este

RU: Приложение не может запуститься, заявляя, что «порт уже используется», но это не так.

VI: Ứng dụng không thể khởi động, thông báo "cổng đã được sử dụng", nhưng thực tế không phải vậy

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