We’ve definitely been bitten by the default being minutely. I’m not sure what a good default would be unless it just complains when the minute is not specified.

I think there are 2 issues here.

Puppet currently complains if I explicitly use ‘’ as a value. It’s not mentioned in the documentation though it seems to work. I’d prefer this to be documented more clearly and to NOT get a warning when using it. By all means provide a different value if that’s really needed, but I think most people know what ‘’ means in cron.¶

Current default behaviour to run minutely jobs could be dangerous. I’d prefer a warning and nothing to happen if no periods are defined at all. That’s safer.¶

Simon Mudd wrote:

I think there are 2 issues here.

Puppet currently complains if I explicitly use ‘’ as a value. It’s not mentioned in the documentation though it seems to work. I’d prefer this to be documented more clearly and to NOT get a warning when using it. By all means provide a different value if that’s really needed, but I think most people know what ‘’ means in cron.¶

That’s a relatively easy fix, but why even bother to specify those?

Current default behaviour to run minutely jobs could be dangerous. I’d prefer a warning and nothing to happen if no periods are defined at all. That’s safer.¶

What about cases where people actually want the cron to run every minute?

I think this is a hard problem, and I’ve generally found that any case where I try to protect users from themselves fails pretty miserably.

Hi Luke.

The answer to “why bother” to specify these is simple: make the configuration explicit, not implicit. It’s much easier to not spot a mistake in a configuration when an action is not SPECIFICALLY mentioned. That’s what makes me uneasy.

Most cron jobs do NOT run every minute, though there are some that might do (and I was configuring such a job), therefore to have the default behaviour to run every minute seems not to be ideal.

If you want to run jobs every minute then as I suggested allow that and also DO NOT complain about explicitly using ‘*’ when specifying the hour or minute.

Again maybe this is just an issue about clearer documentation for this type of resource, and the edge cases.

The current message is not very helpful:

Wed Jul 29 15:45:19 +0200 2009 //Node[dc01mdb-01.mydomain.com]/s_db/s_db::cron/Cron[log_processlist]/hour (notice): defined ‘hour’ as ‘*’

If this is not needed then say so:

Wed Jul 29 15:45:19 +0200 2009 //Node[dc01mdb-01.mydomain.com]/s_db/s_db::cron/Cron[log_processlist]/hour (notice): defined ‘hour’ as ‘’ unnecessarily. Please remove the hour => ‘’ entry as this is the behaviour if not specified.

I’d still prefer a clearer way to explicitly specify minutely jobs.

So what do you recommend as the actual behaviour here? Should the minute just default to ‘0’ or something?

And I’d certainly accept a patch that treated ‘*’ as absent, but that seems like mostly a documentation problem.

I believe this is more about documenting default behavior when user does not specify any schedule. There are some gotchas though.. Currently minutely/hourly/daily etc. is not always assumed (http://projects.reductivelabs.com/issues/1724) which means that behavior is not consistent. I believe the right thing should be: assume ‘’ if parameter is omitted (in any case). Another gotcha is that specifying ‘’ trigger constant update of cronjob eg.

[root@mc01admapp-01 tmp]# puppet -v test.pp notice: //Cron[test_cronjob]/minute: defined ‘minute’ as ‘’ [root@mc01admapp-01 tmp]# puppet -v test.pp notice: //Cron[test_cronjob]/minute: defined ‘minute’ as ‘’

[root@mc01admapp-01 tmp]# cat test.pp cron { “test_cronjob”:

command => "date > /dev/null 2>&1",
minute => '*',

}

whereas anything else it does not:

[root@mc01admapp-01 tmp]# puppet -v test.pp notice: //Cron[test_cronjob]/minute: defined ‘minute’ as ‘*/1’ [root@mc01admapp-01 tmp]# puppet -v test.pp [root@mc01admapp-01 tmp]#

[root@mc01admapp-01 tmp]# cat test.pp cron { “test_cronjob”:

command => "date > /dev/null 2>&1",
minute => '*/1',

}

The documentation for the cron type looks to have been updated. The second sentence notes that leaving period fields blank would result in the command being run every minute. See here for more information:

http://docs.puppetlabs.com/references/stable/type.html#cron

Also, since the default value for each period field of cron itself is *, I would expect entering no periods at all would assume the default values for cron and indeed run the command every minute. Only in the event of specifying a period should the period be changed from default. In my opinion, the current behavior is more logical and preferred.