True. A chapter on using ansible for deploying, unpacking, starting/upgrading a release might be good.
Another suggestion, stick to what you actually use. If you (frigidcode) have experience with production ansible deloyment then maybe don’t also include a puppet/chef chapter. You could instead get collaborators who do use puppet or chef (or one of the many other offerings) to write those chapters.
The reason being, those who have used these tools in anger will know bits that are important to highlight – though obviously need someone who isn’t experienced with these tools to do a review because someone experienced will also accidentally leave out plenty of useful information that someone new will need.
Not to say writing and publishing guides while learning a tool isn’t really useful, I’m just referring explicitly to a book about real world production deployment, as opposed to a “getting up and running with Puppet and Elixir” post.