[CentOS] CentOS 8.1 cron does not send mail

Thu Feb 27 13:42:08 UTC 2020
Jonathan Billings <billings at negate.org>

On Feb 27, 2020, at 08:01, Tobias Kirchhofer <collect at shift.agency> wrote:
> 
> Hi,
> 
> we experience difficulties with crond behaviour sending mail since CentOS 8.1. The cron job is the same like we used in CentOS 7.
> 
> crontab -l
> /usr/bin/python3 -c 'import random; import time; time.sleep(random.random() * 3600)' && /usr/local/bin/backup.sh

Is this literally what your crontab looks like?   Because that’s not valid crontab syntax. 

> backup.sh writes the backup to the remote backup server. There are around 30 machines with the same cron job. The python part spreads the jobs over an hour so that the backup server is not struck at once from about 30 machines.
> 
> The change in behaviour is that crond sends no mail anymore. It is because of the logical and (&&). Without this crond sends mails.
> 
> What has changed in CentOS 8 and does anyone has an idea how we could fix it?

There aren’t any significant changes in ‘cronie’ in 8.1, looking at the spec file. 

Assuming the crontab you wrote above included the time spec too, I’d check to make sure the first command isn’t exiting with a non-zero exit code. 

--
Jonathan Billings <billings at negate.org>