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I scheduled a test at job and reviewed it with atq, but I do not see an atd daemon which will carry them out.

Is this managed within the Solaris / Illumos kernal? If not, which daemon manages at jobs?

I am actually surprised not to find atd, because there is a daemon for cron already.

700 Software
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1 Answers1

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According to the man page of cron in Solaris 10:

NAME

cron - clock daemon

SYNOPSIS

/usr/sbin/cron

DESCRIPTION

cron starts a process that executes commands at specified dates and times.

You can specify regularly scheduled commands to cron according to instructions found in crontab files in the directory /var/spool/cron/crontabs. Users can submit their own crontab file using the crontab(1) command. Commands which are to be executed only once can be submitted using the at(1) command.

cron only examines crontab or at command files during its own process initialization phase and when the crontab or at command is run. This reduces the overhead of checking for new or changed files at regularly scheduled intervals.

As cron never exits, it should be executed only once. This is done routinely by way of the svc:/system/cron:default service. The file /etc/cron.d/FIFO file is used as a lock file to prevent the execution of more than one instance of cron.

cron captures the output of the job's stdout and stderr streams, and, if it is not empty, mails the output to the user. If the job does not produce output, no mail is sent to the user. An exception is if the job is an at(1) job and the -m option was specified when the job was submitted.

cron and at jobs are not executed if your account is locked. Jobs and processses execute. The shadow(4) file defines which accounts are not locked and will have their jobs and processes executed.

So there is no atd in Solaris, one-time jobs are handled by the cron daemon as well.

Laszlo Valko
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  • This is a very common configuration on non-systemd linux and bsd as well. – Andrew Domaszek Dec 18 '15 at 04:04
  • Aha! There it is! .. I'm glad there is a visible daemon for it - as there is for most things. – 700 Software Dec 19 '15 at 03:01
  • BTW. Interestingly Solaris seems to be moving away from `cron` although it will possibly continue to exist in Solaris for the next 20 years or so: In Solaris 11.3 you can now use SMF for periodic jobs (of course you can also still use `cron`) and I suspect it is only a matter of time before one-time jobs can be handled by SMF as well. – peterh Jan 04 '16 at 09:23