[SOLVED] AT command shows active, but does not run

scottieH · 05-02-2023, 04:27 PM

I'm on Red Hat 7.9. AT version is 3.1.13.
I schedule an AT job

Code:

$ at <HH:MM>
at> echo "UserA at job works" > /tmp/UserA.out
at> <EOT>

at -l shows the job scheduled

Code:

$ at -l
7 <Date/Time of execution> a UserA

When the execution time comes, the status changes to =

Code:

$ at -l
7 <Date/Time of execution> = UserA

This command should take a fraction of a second to execute. Just for fun, let's wait 5 minutes.

Code:

sleep 300
$ at -l
7 <Date/Time of execution> = UserA
$ ls -l /tmp/UserA.out
ls: cannot access /tmp/UserA.out: No such file or directory

/var/spool/at shows the generated file:

Code:

# ls -l /var/spool/at
-rwx------ UserA  UserGroup  5536 <creation date> =00007#####
drwx------ root  root         138 <Execution Date> spool

# ls -l /var/spool/at/spool
-rwx------ UserA  UserGroup    52 <Execution Date> a00007#####

I can execute the file /var/spool/at/=00007##### and it works correctly with a return code of 0.

The spool file /var/spool/at/spool/a00007##### just contains:

Code:

Subject: Output from your job     7
To: UserA
<blank line>

Has anyone seen this? Solution or Ideas?
TIA

michaelk · 05-03-2023, 10:55 AM

It works for me on a CentOS 7 VM and it should work the same. Try:

Code:

 echo "Hello" > /tmp/UserA.txt | at now +1 minutes

scottieH · 05-09-2023, 12:36 PM

Quote:

Originally Posted by michaelk

It works for me on a CentOS 7 VM and it should work the same. Try:

Code:

 echo "Hello" > /tmp/UserA.txt | at now +1 minutes

It queues and switches to active, but does not run.

Racho · 05-09-2023, 02:10 PM

Try this:

Code:

echo "echo $(date) >> /tmp/UserA.txt" | at now +1 minutes

And at will execute the command echo $(date) >> /tmp/UserA.txt

jayjwa · 05-20-2023, 04:01 PM

IIR, there's a load avg restriction with "at". It won't run if your load is above that. Here, I had to change the default to something higher. There's an "ATD_OPTS" in /etc/default/atd (in my distro, might be different in yours).

Code:

# Default options for the atd daemon:
#
# -b 15: minimal interval in seconds between two jobs
# -l 3: do not start new jobs if the load average is above 3
ATD_OPTS="-b 15 -l 3"

Slackware might use some different directories than your OS, but this is what I see:

Code:

ls -l /var/spool/
total 64
drwxrwx--T 2 daemon daemon 4096 May 20 16:57 atjobs/
drwxrwx--T 2 daemon daemon 4096 May 20 16:57 atspool/

scottieH · 05-31-2023, 04:53 PM

I found it. The file /etc/pam.d/atd is incorrect and it prevents the at daemon from authentication.
I copied /etc/pam.d/crond to atd and it works!
This issue is fixed in atd v 3.1.23-2