Is there a utility/library that facilitates the coordination of tasks between multiple servers? For me, I need to run scheduled tasks, copy lots of data between servers, and restart processes (a series of dependent operations that occur on different machines in a cluster).
I can go with cronjobs and batch scripts, although I can't help thinking that there's a more robust and elegant way of going about this.
Capistrano is a tool for automating tasks across servers, it does exactly what you ask. It's written in Ruby and uses SSH to communicate with the other machines.
As mentioned, Capistrano can be used to automate tasks. It was originally written to deploy Rails applications consistently, but it has become a very robust sysadmin tool. It is generally best for adhoc one time commands and application deployments though. If you need multiple systems managed with a consistent configuration tool, I suggest Puppet.
We use Puppet to manage overall system configuration for Rails, Django and PHP based web/db/app servers, and we use Capistrano for application deployments and single commands (like running Puppet after a config change).