cron usage and squid daily log rotate

[Harry Hoffman]

This is all documented very nicely in the cron manpage:

$man cron
Cron should be started from /etc/rc.d/init.d or /etc/init.d

Cron  searches  /var/spool/cron for crontab files which are named after
accounts in crontabs found are loaded into memory.  
Cron also  searches for /etc/crontab and the files in the directory,
which are in a different format (see crontab(5) ).  Cron then wakes up
every minute, examining  all  stored crontabs, checking each command to
see if it should be run in the current minute.  When  executing
commands, any  output  is mailed  to the owner of the crontab (or to the
user named in the MAILTO environment variable in the crontab, if such
exists).

If we look at /etc/crontab we see how each of the
cron.{hourly,daily,weekly,monthly} crontabs are executed:

$cat /etc/crontab
SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=root
HOME=/

# run-parts
01 * * * * root run-parts /etc/cron.hourly
02 4 * * * root run-parts /etc/cron.daily
22 4 * * 0 root run-parts /etc/cron.weekly
42 4 1 * * root run-parts /etc/cron.monthly

And if we look at the file in /etc/cron.daily we see a crontab for
logrotate.

Because cron.daily is run every morning at 4:02am we can expect
logrotate to run around that time.


The logrotate script say to move the squid log files out of the way
/var/log/squid/access.log {
    weekly
    rotate 5
    copytruncate
    compress
    notifempty
    missingok
}
... <snipped other logfile entries>

/var/log/squid/store.log {
    weekly
    rotate 5
    copytruncate
    compress
    notifempty
    missingok
# This script asks squid to rotate its logs on its own.
# Restarting squid is a long process and it is not worth
# doing it just to rotate logs
    postrotate
      /usr/sbin/squid -k rotate
    endscript
}

The final logrotate statement above tells squid to rotate the log files:
/usr/sbin/squid -k rotate


For other ways of rotating the logs the Squid FAQ is indespensible:
http://wiki.squid-cache.org/SquidFaq/SquidLogs#head-df8a4e31ffc62c98268eb3e7774f7c4f0735fac9

and/or here:

http://docstore.mik.ua/squid/FAQ-6.html


HTH.

Cheers,
Harry


On Mon, 2009-03-02 at 10:24 +0200, a bv wrote:
> Hi all,
> 
> I would like to daily logrotate the squid log files at everyday at
> 00:00(midnight) at some RHEL 5.x systems. I havent used cron things
> for a long time so i forgot all about it. Also i have the
> logrotate.conf  and /etc/logrotate.d/squid file.
> 
> i have tried to add a /usr../sbin/rotate -k thing as a cron job but it
> seem to be unsuccessfull.  Googling makes some mind mixing samples
> etc. also using crontab -e command brings an empty file, other than
> the one i find crontab.
> 
> So is there someone who will shortly explain the cron related files
> and usage , also making the squid rotate its daily logs easily.   Most
> of the resources (including books) makes confusing the minds at these
> simple subjects. Couldnt see  a step by step guide.
> 
> Regards
>