App writes to ".log.1" file instead of ".log" file after running logrotate

Question

After force running logrotate, my app keeps writing to my_app.log.1 (the old log that should be archived later) instead of my_app.log.

This make my_app.log an empty file, therefore logrotate runs without any effect. And my_app.log.1 keep growing to gigabytes.

I am running Ubuntu 12.04. My app is a Node.js app using pm2. Following is my logrotate configuration:

"/var/log/my_app/*.log" {
  daily
  size 50M
  rotate 10
  missingok
  compress
  delaycompress
  notifempty
}

I know I put notifempty there, but why is my_app.log.1 written to in the first place?

Answer 1

I finally figured out how to solve the problem.

This was because the log file was being written by pm2. logrotate changed its name to my_app.log.1 and created new my_app.log file, but pm2 did not care about this and kept writing to my_app.log.1.

I solved the problem by replacing the notifempty option by copytruncate and then restarted pm2. After fixing, notifempty can be added back but I do not really need it.

See the logrotate reference for more information. Hope this will help other folks getting a similar problem.