Question: I have the following problem:

* too many machines.
* some groups of machines share the same cron configuration, some not.
* sometimes, I need to add a crontab entry manually in hundreds of machines.
* I'm always making mistakes, which my B.O.S.S doesn't seem to like...

Is there some tool hopefully (with a web interface, and gnu) to manage this sort of thing?

Thanks wise people !!
CM

Answer: 
*Configuration management systems* such as [Puppet](http://reductivelabs.com/trac/puppet), [Capistrano](http://www.capify.org/index.php/Capistrano) and [CFEngine](http://www.cfengine.org) are tools which will do this and a whole lot more.

If you're having to manage many machines for cron, you'll probably have a bunch of other things you have to configure on those machines too, so sooner or later you'll need to investigate more than just managing the cronjobs...

They have very good tutorials and documentation on the Puppet site ([see here](http://reductivelabs.com/trac/puppet/wiki/GettingStarted)), and they're not too painful to get set up.

If it's hundreds of machines, get up and running with them as soon as you can and you'll wonder how you managed to cope without them (even for something simple like just pushing the cronjobs to lots of machines)!
With a configuration management tool like puppet (or cfengine, bcfg2, etc.), you can manage a lot more than crontabs from a centralized location.