0

I'm running Ubuntu Server 16.04.2 LTS. I'm seeing CRON logs in my auth.log file every 5 minutes:

Mar 12 06:25:10 MEDIASERVER CRON[19470]: pam_unix(cron:session): session closed for user root
Mar 12 06:30:01 MEDIASERVER CRON[19580]: pam_unix(cron:session): session opened for user root by (uid=0)
Mar 12 06:30:02 MEDIASERVER CRON[19580]: pam_unix(cron:session): session closed for user root
Mar 12 06:35:01 MEDIASERVER CRON[19594]: pam_unix(cron:session): session opened for user root by (uid=0)
Mar 12 06:35:01 MEDIASERVER CRON[19594]: pam_unix(cron:session): session closed for user root

My crontab is the following:

0,30 * * * * /usr/local/bin/ipmon.sh >/dev/null 2>&1    # Monitor IP change every half hour
0 0 1 * * /usr/local/bin/backup.sh >/dev/null 2>&1  # Regular backup every month

Correct me if I'm wrong, but the first job should execute every half hour and the second should execute once per month. Why is there a cron job executing every 5 minutes ?

Thanks.

EDIT:

/etc/crontab:

SHELL=/bin/sh
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin

# m h dom mon dow user  command
17 *    * * *   root    cd / && run-parts --report /etc/cron.hourly
25 6    * * *   root    test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.daily )
47 6    * * 7   root    test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.weekly )
52 6    1 * *   root    test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.monthly )
#

/etc/cron.d/sysstat

# The first element of the path is a directory where the debian-sa1
# script is located
PATH=/usr/lib/sysstat:/usr/sbin:/usr/sbin:/usr/bin:/sbin:/bin

# Activity reports every 10 minutes everyday
5-55/10 * * * * root command -v debian-sa1 > /dev/null && debian-sa1 1 1

# Additional run at 23:59 to rotate the statistics file
59 23 * * * root command -v debian-sa1 > /dev/null && debian-sa1 60 2

/etc/cron.d/popularity-contest

SHELL=/bin/sh
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
56 16 * * *   root    test -x /etc/cron.daily/popularity-contest && /etc/cron.daily/popularity-contest --crond

The closest job is sysstat, which runs every 10 minutes, but it still doesn't explain the 5 minute interval in the logs.

lsb_release -a

Distributor ID: Ubuntu
Description:    Ubuntu 16.04.2 LTS
Release:    16.04
Codename:   xenial
  • can you edit your question to include the content of /etc/crontab? – Nick Sillito Mar 14 '17 at 18:40
  • 2
    ...and the content of any files in /etc/cron.d/ ? – user535733 Mar 14 '17 at 18:40
  • @user535733 MEDIASERVER is just the host name. – Jos Mar 14 '17 at 18:42
  • Welcome to askubuntu! Please edit the output of lsb_release -a into your post. At first glance, this looks like a really old bug – Elder Geek Mar 14 '17 at 19:11

Your Answer

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Browse other questions tagged or ask your own question.