title: Ansible best practice for passing vars to nested playbooks?
body: <p>So I am trying to wrap my head around Ansible and building a simple LEMP stack. I decided to work with a <a href="https://github.com/ansible/ansible-examples/blob/master/language_features/nested_playbooks.yml" rel="nofollow">nested playbook</a> because I want to compartmentalize as much as possible, while learning. I run in to this issue where I need to pass some variables such as the root password of mysql. Now I wonder if there is any best practice passing varibles from the main playbook down to the individual plays or should the varibles be set in the individual sub-playbooks? I am using <a href="https://github.com/francisbesset/ansible-playbooks" rel="nofollow">this repo</a> as a basis for my own project. I also wonder how overriding works with varibles, if a default value is set in the sub-playbook does the variables set in the main playbook override this value?</p>