So I'm running a shared platform with about 80 apps on it.

Out of that 80 or so apps a few have crontab access which is managed through group membership.

I need to design a system that will once an hour through a root cronjob, scan the project space of those that have crontab access (Belong to bppcron group) and within that project space I'm looking for /proj/<project name>/www/.crontab-admin/crontab-DEV (Or crontab-QA Or crontab-PROD). From there i run a diff -q | wc -l against an if logic checking for 1 or 0. If it's different run crontab -u <user> crontab-DEV (Or Crontab-QA, crontab-PROD)

This root cronjob will be run locally on each host. This logic makes sense for non-load balanced env's, but how would I be able to do this in a load balanced environment? I have two QA servers and four Production servers.

Any thoughts?

It might depend on your load balancing scheme. How do you have it set up?

There are few commercial scheduling programs to do this job easy.

On linux there is a /etc/cron.hourly.

If you plan on coding something using php make sure you include #!/path/to/php at the very top of the file so that it can be run under CLI as an application.

Hope this helps.