Red Hat Bugzilla – Bug 81078
atd should not be run by default because it does nothing by default
Last modified: 2007-04-18 12:49:30 EDT
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Description of problem:
All versions of Red Hat I've seen, including the latest
phoebe beta release, run atd by default and yet this
daemon does absolutely nothing by default ! Hence, I am
proposing that atd isn't run by default in future
releases of Red Hat.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Install pretty well any version of Red Hat (e.g. the phoebe beta)
2. After logging in, do "ps -ef" to see if atd is running
3. Check the default atd config (/etc/at.allow, /etc/at.deny,
4. Read "man atd".
Actual Results: atd is always run every time any default-installed version of
Red Hat is booted and it remains running all the time.
The default atd config has no "at" jobs at all. There is no
shipped /etc/at.allow, /etc/at.deny is "empty" (one blank line) and
/var/spool/at is empty too.
The man page for atd states, as a "bug":
"The functionality of atd should be merged into cron(8)."
Expected Results: Either atd should do "something" timed by default (note that
cron/anacron *does* have several shipped cron jobs by default, but
"at" doesn't) or it should not be run by default. It's as simple as
I have never bothered using the "at" suite either on Linux or
on commercial UNIXes, because "cron" basically does all you need
for timed jobs. Even the atd author is implying in the atd man page
that the command is redundant and any non-cron functionality should
be added to cron rather than atd being run.
Hence, this is a request for enhancement that atd is no longer run
at startup - it certainly should be shipped/installed with future
Red Hat distros in case someone does indeed want to run it, but it's
plainly crazy for it to be run by default.
Maybe you're right, While I don't use "at" myself, I could
imagine some users may well use it for running one time jobs at a certain time.
Atd is only using about 500kB of memory on my machine - it doesn't seem
to use too many resources.
How serious do you think this problem is?
I'm not the original poster, but I'd be in favor of the change
(assuming it is very explicitly mentioned in release notes and
at seems to be a standard UNIX tool (mentioned in the canocnical
books), but I've never seen anyone using it either.
As for "only 500 KB": I've got too many programs requiring
"only 500 KB" running unneeded most of the time. Count also
the half a second at system boot ;-)
It should be noted here that the proposal is simply to turn off atd at the
various runlevels, which I can do (and do indeed do !) with this command after
chkconfig --level 0123456 atd off
It's not proposed that atd isn't installed by default - it's only that atd
isn't actually run by default when the machine is booted. Unlike processes
like gpm - which *do* something [mouse can move cursor on the console] by
default - atd is a process that really does nothing by default. Why run
something permanently in the background on boot that does absolutely nothing by
default unless the user bothers to configure it, especially when an adequate
alternative, cron, is available anyway ?
One thing that atd provides that crond doesn't, is the "batch" service,
which runs something when the system-load goes below a
certain level - I don't think crond provides such functionality.
Anyway under your suggestion is still under consideration.
I still think that "at" and "batch" are useful enough and
expected to work out of the box on un!xes that they warrant
having atd running by default. So I'm going to close this