Been learning and playing with Ansible this week as a CM tool.
What do we use it for?
After you spin up an EC2 instance you can use a Ansible to add users/groups, ssh keys, install packages all from a Ansible playbook (script). It’s similar to chef / puppet.
If you have to provision multiple instances this can be a time saver. Also say a new member has joined. How can add this new member to all your instances without doing it manually. Ansible solves this issue because you can create a playbook that adds the user to all hosts easily.
I bricked an instance by corrupting a /etc/sudoers file. That was bad but learned there is a way to validate any changes to that file.
Better practice is to not edit the /etc/sudoers file but to create new files at /etc/sudoers.d/ at least on Ubuntu
Mitchell Fang's Coding 