New"Address already in use": find who is using port 80 (or any port)

Shell, we have a problem!

Real fixes for problems with operating systems, containers and databases. Explained step by step — and you can try every fix right here in your browser.

Open the terminal Browse the fixes

guest@ohsudo: ~

guest@ohsudo:~$ sudo systemctl status nginx

● nginx.service - A high performance web server

Active: failed (Result: exit-code)

guest@ohsudo:~$ journalctl -u nginx -n 1

nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address in use)

# Shell, we have a problem! Who owns port 80?

guest@ohsudo:~$ sudo ss -tlnp | grep :80

LISTEN 0 511 0.0.0.0:80 users:(("apache2",pid=812))

guest@ohsudo:~$

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guest@ohsudo:~$ ls /var/log
auth.log nginx/ syslog
guest@ohsudo:~$ ▋

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bind() to 0.0.0.0:80 failed (98: Address already in use)

"Address already in use": find who is using port 80 (or any port)

Fix "bind() failed (98: Address already in use)": find the process holding the port with ss or lsof, then stop it, move it, or change your port.

Beginner · 4 min read

Docker & Containers

Docker "exited with code 137": OOM kill or a stop that took too long

Exit code 137 means the container was killed with SIGKILL. Find out if it ran out of memory or ignored docker stop, and fix each case.

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CrashLoopBackOff

Kubernetes CrashLoopBackOff: 7 causes and how to find yours

CrashLoopBackOff means the container keeps exiting. Read the exit code and the previous logs, then fix the crash, OOM kill, probe or command.

Intermediate · 5 min read

ERROR 1045 (28000): Access denied for user

MySQL ERROR 1045 (28000): Access denied for user — find which part is wrong

Fix MySQL "ERROR 1045 Access denied for user": check the user@host account, the password, socket vs TCP, option files, and Docker init passwords.

Beginner · 5 min read

502 Bad Gateway

Nginx "502 Bad Gateway": find the cause in the error log

Fix nginx 502 Bad Gateway: read error.log, then fix the backend that is down, the wrong address or socket, the crashing app, or SELinux on RHEL.

Intermediate · 5 min read

No space left on device

No space left on device: find what is filling your Linux disk

Fix "No space left on device" on Linux: find the biggest directories and files, free space safely, and handle the cases where df says there is space.

Beginner · 4 min read