How to properly automatically/manually rotate log files for production Rails App

Question

I am taking over administration for a server which has a custom made 3rd party Rails app. The app developer informed me that the ruby log files are getting large and pointed me to the following link: - https://stackoverflow.com/questions/4883891/ruby-on-rails-production-log-rotation

The logs are located in /root/production/app/log. This folder contains several files which end in .log. The current log files are about 2GB in size and the folder also has archived log files with the format of "logname.log.2013_01_18.bz2".

I tried searching the ssh command history to see if I can see which command was used to create the archive files, but the commands don't go back that far. I also ran "cat /var/lib/logrotate/status" but it doesn't look like logrotate did not rotate any logs from the above folder.

Basically:

1. I would like to be able to run a command to rotate the logs manually and/or have the logs rotate automatically every Sunday night.
2. If I need to shutdown my rails app to rotate the logs, I have no problem with this as I have a maintenance window every Sunday night to perform this.
3. Finally, I am not sure if I should compress the log files weekly into bz2 or only compress the logs on a monthly basis for any rotated logs related to the previous month. This is mainly because I am not sure exactly how this app utilizes the logs and I have never utilized rails apps nor have I had to configure log rotation manually.

At this moment I do need to keep all log files and not discard any. Any information on concerns related to rotating logs, such as backing up logs before attempting to rotate are welcome.

Answer 1

logrotate is used by the system to rotate logs so you have 2 choices. You can either incorporate the rotation of these app logs into the systems rotations or setup your own and either run them manually or from the root user's crontab (Assuming the Rails app is run as root given it's directory is /root/...).

System rotation

To setup a logrotation within the system's pre-existing ones simply add a new file to the directory /etc/logrotate.d. Call it railsapp.conf. I'd use the other examples there to construct it. Also confrere with the logrotate man page.

User rotation

If you want to run your own instance of logrotate you only have to provide it with command line switches to do so.

1. First make a copy of /etc/logrotate.conf /root/rails_logrotate.conf
2. Edit the file so that it has the log rotation configured the way you want (i.e. keep all logs, rotate weekly, etc.)

3. Run it

   # 1st time
   $ logrotate -d -f -s $HOME/my_logrotate.state logrotate.conf
   
   # afterwards
   $ logrotate -d -s $HOME/my_logrotate.state logrotate.conf
   

   If things look OK you can re-run these commands without the -d switch. This is for debugging purposes only and won't actually do any of the tasks, merely show you what it WOULD do.

   $ logrotate -s $HOME/my_logrotate.state logrotate.conf     
   

   You could also use the -v switch to make it verbose, similar to the output seen when using the -d switch.

Example

1. Start with this log file.

   $ dd if=/dev/zero of=afile bs=1k count=10k
   10240+0 records in
   10240+0 records out
   10485760 bytes (10 MB) copied, 0.0702393 s, 149 MB/s
   
   $ ll afile
   -rw-rw-r-- 1 saml saml 10485760 Aug  6 14:37 afile
   
   $ touch -t 201307010101 afile
   $ ll afile
   -rw-rw-r-- 1 saml saml 10485760 Jul  1 01:01 afile
   

2. Now run logrotate

   $ logrotate -v -f -s $HOME/my_logrotate.state logrotate.conf
   reading config file logrotate.conf
   reading config info for /home/saml/afile 
   
   Handling 1 logs
   
   rotating pattern: /home/saml/afile  forced from command line (1 rotations)
   empty log files are rotated, old logs are removed
   considering log /home/saml/afile
     log needs rotating
   rotating log /home/saml/afile, log->rotateCount is 1
   dateext suffix '-20130806'
   glob pattern '-[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]'
   glob finding old rotated logs failed
   renaming /home/saml/afile to /home/saml/afile-20130806
   creating new /home/saml/afile mode = 0664 uid = 500 gid = 501
   

3. Check the results

   $ ll afile*
   -rw-rw-r-- 1 saml saml        0 Aug  6 14:40 afile
   -rw-rw-r-- 1 saml saml 10485760 Jul  1 01:01 afile-20130806
   

Weekly Cron

To make this run every Sunday you could create the following crontab entry for the root user.

$ crontab -e

Add the following lines:

# Example of job definition:
# .---------------- minute (0 - 59)
# |  .------------- hour (0 - 23)
# |  |  .---------- day of month (1 - 31)
# |  |  |  .------- month (1 - 12) OR jan,feb,mar,apr ...
# |  |  |  |  .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat
# |  |  |  |  |
# *  *  *  *  * user-name  command to be executed
0 0 * * sun logrotate -v -f -s $HOME/my_logrotate.state $HOME/logrotate.conf

Then save the above.

You can also use these types of shortcuts instead of specifying the actual days, mins, secs, etc.

string         meaning
------         -------
@reboot        Run once, at startup.
@yearly        Run once a year, "0 0 1 1 *".
@annually      (same as @yearly)
@monthly       Run once a month, "0 0 1 * *".
@weekly        Run once a week, "0 0 * * 0".
@daily         Run once a day, "0 0 * * *".
@midnight      (same as @daily)
@hourly        Run once an hour, "0 * * * *".

References

• HowTo: The Ultimate Logrotate Command Tutorial with 10 Examples
• Cron and Crontab usage and examples