Does this sound familiar: You set up a server and finally get it to work after hours of googling. Somehow. ...until it crashes, or the vendor goes out of business, or it needs an update, or your intern (who has a little too much access) deletes it (whoops). What to do then?
Ansible solves this. You can create sets of instructions to set up whole servers or even just to run specific tasks, e.g. copying databases and changing settings quickly during a server migration.
It is easy to learn; it uses YAML, like Drupal 8. I tried Chef, Puppet, and maybe more before this, but I didn't stick with anything until Ansible.
You'll wonder what you were doing without it.