Day: October 15, 2021

Application Stopped due to upstream unreachable

Posted on by Bian Xi Leave a Comment on Application Stopped due to upstream unreachable

Application Stopped due to upstream unreachable

During Chef Server troubleshooting time, found chef is unreachable from localhost

Description

  • Nginx was shown as started in chef-server-ctl status command, pid could be found
  • TCP port 443 was inaccessable from localhost.
  • Reboot server, but still the same issue
  • Used ps -ef | grep nginx, found nginx is running without indication of master
  • Run nginx command line which found in ps
  • Shows upstream server and port was not reachable, which is automate server

Result

  • Can not find IP address, then add IP and host into /etc/host file, result shows

    • NGINX running with master indicator
    • TCP port 443 was listening

  • Still can not reach upstream server

Consolution

The problem could be related to following issues caused application stopped due to no IP can be found for upstream servers.

  • Routing issue
  • Firewall issue

Process Listening on a Particular Port in Linux

Posted on by Bian Xi Leave a Comment on Process Listening on a Particular Port in Linux

Process Listening on a Particular Port in Linux

These commands might not workable in some Unix like systems.

Using netstat

netstat -ltnp
netstat -peanut

lsof

lsof -i :80

fuser

fuser 80/tcp

ss


ss -nlp
``

## References

[3 Ways to Find Out Which Process Listening on a Particular Port](https://www.tecmint.com/find-out-which-process-listening-on-a-particular-port/)