Ansible is a tool to automate repetitive tasks like setting up and configuring servers or deploying updates.
It can automate tasks on multiple hosts, and has made my life simpler. When I tell other developers about it, I sometimes get the response that “Well I could just write a shell script for that” — and while yes you could, it’s much more flexible and is configured using YAML which is just a bit more readable. In addition to it being human readable it’s also cross platform and secure (it relies on open ssh and doesn’t depend on agents).
This is a small playbook to install WordPress running on Nginx for creating new local development environments and test servers: https://github.com/tucsonlabs/ansible-playbook-wordpress-nginx