topic Re: Cron execution & system time in Operating System - HP-UX

Cron execution & system time

SteveR77 — Fri, 21 Aug 2009 04:55:46 GMT

I have recently run into an issue of my cron jobs exectuing an hour earlier than they are scheduled. However, the log for the crontab posts that it ran at the time which was set in the crontab even though when a date command is executed there is a difference of an hour.

For example the cron post 17:00 for it's execution time but the server's date will show it is only 16:00.

I've stopped and started the cron service, triple checked all the timezone parameters which are set properly to Central time for the US.

I've run out of options to check or try to resolve this so any insight that can be shed is most welcome.

Re: Cron execution & system time

Dennis Handly — Fri, 21 Aug 2009 05:01:42 GMT

What do these show:
date; date -u
echo $TZ

Did you change /etc/TIMEZONE without restarting cron?

Re: Cron execution & system time

SteveR77 — Fri, 21 Aug 2009 05:28:45 GMT

Results of date commands -

date ; date -u
Fri Aug 21 01:33:03 CDT 2009
Fri Aug 21 06:33:03 UTC 2009

Result of echoing timezone variable -

echo $TZ
CST6CDT

Finally, no to my knowledge there have been no timezone adjustments on this server

Re: Cron execution & system time

Hakki Aydin Ucar — Fri, 21 Aug 2009 05:57:11 GMT

it remind of an ambiguous event I faced on our customer Solaris Servers. Problem was very same. Even though I rebooted server not solved issue, but 3 or 5 days later problem solved by the system itself.

I just recommend to reboot server if you are free to do.

Re: Cron execution & system time

SteveR77 — Fri, 21 Aug 2009 06:36:07 GMT

Thank you, unfortunately this server reboots every night but the issue has not corrected itself even after two days.

Re: Cron execution & system time

Dennis Handly — Fri, 21 Aug 2009 06:36:09 GMT

> Results of date commands & Result of echoing timezone variable

You seem to have your clock correct.

>even though when a date command is executed there is a difference of an hour.

How do you know this?
Did that date include your timezone?
Can you start a cronjob and do the above date and echo commands?

Note that in a cronjob, TZ isn't likely to be set correctly.

>For example the cron post 17:00 for it's execution time but the server's date will show it is only 16:00.

This implies that cron has TZ set to EST5EDT?

>Hakki: I just recommend to reboot server if you are free to do.

It might be just easier to stop and restart cron:
/sbin/init.d/cron stop
/sbin/init.d/cron start

Re: Cron execution & system time

SteveR77 — Fri, 21 Aug 2009 06:47:18 GMT

The service was stopped and restarted using:
/sbin/init.d/cron stop
/sbin/init.d/cron start

The date does show the timezone correctly as CDT.

I can create a script to capture what cron believes the TZ and time settings are

At this moment, I have reviewed what the environment has for the timezone and all that I could see is correct. Also this server does not do any time synchronization so that is not a variable that could be causing this.

Thanks once again.

Re: Cron execution & system time

Vijaykumar_1 — Fri, 21 Aug 2009 11:22:07 GMT

Can you pls post your cron entry here..

Re: Cron execution & system time

SteveR77 — Fri, 21 Aug 2009 12:16:12 GMT

Everyone,

Thank you for your assistance. The cron service was getting the default of EDT. While the rest of the environment was CDT.

I'm reviewing the init.d configuration but I believe I have this resolved.

Re: Cron execution & system time

Dennis Handly — Fri, 21 Aug 2009 23:58:43 GMT

>The cron service was getting the default of EDT.

My crontab entries set TZ when I start my scripts:
* * * * * export TZ=XX; ...
Or put that in your scripts.