Repo URL:
https://github.com/jamesrwhite/minicron
The idea here is that one server holds the "hub", aka the Minicron server. The other servers are simply clients. We use ssh tunneling from clients to communicate with the server. The server should be able to ssh into the client machines, in order to modify the client's crontab. We add public keys with a prefix that only allow root ssh access from a single IP (the server's IP).