Ansible facts

Ansible has some useful built-in variables. Most of them seem to be built in to /usr/local/lib/python2.7/site-packages/ansible/module_utils/facts.py

List all variables on a particular machine

ansible -m setup <hostname>

Some useful Variables

ansible_os_family                  == "RedHat"
ansible_distribution               == "Debian"
ansible_distribution_major_version == "7"