[PLUG] Cron advice needed

[Louis Kowolowski]

On Apr 25, 2016, at 11:12 AM, Don Buchholz <buchholz at easystreet.net> wrote:
> 
>> …
>> the command `crontab -e` creates a copy of your crontab file in /tmp.
>> After you complete your editing and save it the crontab program checks it for
>> validity before copying the version in /tmp to the real crontab - in your example
>> it is probably /var/spool/cron/jjj or /var/spool/cron/crontabs/jjj
>> 
>> No, not in ~/ the folks who created cron decided that all cron files on a system
>> should be stored in the same place.
> 
> In a true NFS environment, you would almost certainly not want
> your crontab kept in $HOME.  Consider an network with ~100 work-
> stations and a single NFS server providing $HOME for the entire
> userbase.  When you schedule a task for 3pm, which one of the
> 100+ systems should run that job?  This is why job scheduling
> is managed on a local filesystems (e.g. /var, /etc, …).
> 
Even if you store(d) it in ~/, all the systems I’ve used, require that the user manually tell the system to use a crontab file (regardless of where it is), so theoretically, this would still work. That said, unless you uniquely named them, or provided unique paths to them, its a recipe for bad things to happen in a quasi-automated fashion.

I’m imagining a cron job that is supposed to run every 5m and generates an email, running on hundreds (or thousands if you have a larger environment) of hosts, generating errors on all but 1. Waking up to 10,000 emails all from cron.

--
Louis Kowolowski                                louisk at cryptomonkeys.org <mailto:louisk at cryptomonkeys.org>
Cryptomonkeys:                                   http://www.cryptomonkeys.com/ <http://www.cryptomonkeys.com/>

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