[SOLVED] Crontabs/cronjobs not working

[JohnTanner]

Hello everyone,

i am currently facing a problem where I have some entries in my crontab (crontab -e) and in /etc/crontab. These lines or commands work on their own when I execute them via the web shell, but cron just does not execute them. there is no mail in /var/mail and no other indication of an error. I have also tried many variations of the commands (just execute a script to make the machine sleep via rtcwake) and pipe the result into a txt file but also to no avail.

i have the same problem in all of my LXC containers, so does anyone have an idea why that is?
any suggestions are very welcome

 

[Stoiko Ivanov]

Two potential points:
* try using full paths for your scripts (cronjobs usually have only /usr/local/bin:/usr/bin:/bin as their PATH)
* not getting mails is odd - but does the container have a mailserver configured (e.g. postfix)?

I hope this helps!

 

[JohnTanner]

Two potential points:
* try using full paths for your scripts (cronjobs usually have only /usr/local/bin:/usr/bin:/bin as their PATH)
* not getting mails is odd - but does the container have a mailserver configured (e.g. postfix)?

I hope this helps!

thanks for the reply!

the script is located in / so my crontab is

0 23 * * 1 /sleep

. The way I understand it, the node this is located on, should then execute the script sleep in / at 11pm, where the content is

#!/bin/sh
rtcwake -m mem -l -s 28800

and I meant the mail in /var/mail. is postfix required for that as well?

 

[Stoiko Ivanov]

The way I understand it, the node this is located on, should then execute the script sleep in / at 11pm, where the content is

yes - but only on monday - the 5th field is the day of week (1 denoting monday)

and I meant the mail in /var/mail. is postfix required for that as well?

yes

 

[JohnTanner]

yes - but only on monday - the 5th field is the day of week (1 denoting monday)


yes

yeah I know it's for Monday only (I have one for every day of the week).
The task is not being executed and postfix is installed on the node, yet the /var/mail/ directory is empty

any ideas?

 

[Stoiko Ivanov]

* check the journal - if a cronjob is started it should show up in the journal
* where is `rtcwake` - try using the full path there as well

I hope this helps!

 

[JohnTanner]

* check the journal - if a cronjob is started it should show up in the journal
* where is `rtcwake` - try using the full path there as well

I hope this helps!

ah the damn journal... I'll check that later; thanks for the tip

and I'll try the whole path to rtcwake too

 

[JohnTanner]

ok solved it:

it was just me being stupid...

in the crontab -e and/or in /etc/crontab, the fully qualified paths are required. say: /sbin/rtcwake and so on

same goes with the LXC crontabs (ubuntu 19.04 template). Thats also confusing me, on an entirely different machine, i got snapraid to work with just "snapraid sync" in the crontab -e...

Cron works now and my nodes go into standby at the right time.

thanks a lot for your help @Stoiko Ivanov !