This the final part of the detailed look at Packt book, Learning Ansible. As the book says in the opening to chapter 6 we’re into the back straight, into the final mile. The first of two final chapters look at provisioning of platforms on Amazon AWS, DigitalOcean and the use of the very hip and cool Docker plus updating your inventory of systems given that we have dynamically introduced new ones. The approach is illustrated by not only instantiating servers but delivering a configured Hadoop cluster. As with everything else we’ve seen in Ansible there isn’t a standardised approach to all IaaS platforms as that restricts you the lowest common denominator which is contrary to Ansible goals described early on. But deploying the Hadoop elements on the two cloud IaaS providers is common. Although the chapter is pretty short, I did have to read through this more carefully, as the book leverages a lot of demonstrated features from previous chapters (configuration arrays etc) which meant seeing the key element of the interaction with AWS was harder. It does mean if you tried diving into this chapter straight away, although not impossible does require a bit more investment from the reader to see all the value points. That said it is great to see through the use of the various features how easy to setup the provisioning in the cloud is, and the inventory update. Perhaps the win would have been to just so the simple provision and then the clever approach.
Chapter 7 focuses on Deployment. When I read this, I was a little nonplussed, hadn’t we been reading about this in the previous 6 chapters. But when you look at the definition provided:
“To position (troops) in readiness for combat, as along a front or line.”
Excerpt From: “Learning Ansible.” Packt Publishing.
You can start to see the true target of what we’re really thinking about, which is the process of going from software build to production readiness. So having gone through the software packaging activities you need to orchestrate the deployment across potentially multiple servers across a server farm. This orchestration piece is really just pulling together everything that has been explained before but also share some Ansible best practise. Then finally an examination of the Ansible approach for the nodes to pull deployments and updates.
The final piece of the book is an Appendix which looks at the work to bring Ansible to the Windows platform, Ansible Galaxy and Ansible Tower. Ansible Galaxy is a repository of roles build by the Ansible community. Ansible Tower provides a web front end to the Ansible server. The Tower product is the commercial side of the Ansible company – and effectively sales here fund the full time Ansible development effort.
So to summarise …
The Learning Ansible book explains from first principles to the very rich capabilities of building packaging software, instantiating cloud servers or containers through to configuring systems and deploying applications into new environments; and then capturing instantiated system details into the Ansible inventory. How Ansible compares with the more established solutions in this space in the form of Puppet and Chef is discussed, and the pros and cons of the different tools. All the way through, the books has been written in an easy engaging manner. You might even say wonderfully written. The examples are very good with the possible exception of 2 cases (just merely good in my opinion), the examples are supported with very clear explanations that demonstrate the power of the Ansible product. Even if you choose not to use Ansible, this book does an excellent job of showing the value of not resorting to the ‘black art’ of system build and configuration and suggesting good ways to realising automation of this kind of activity, in many place undoubtedly thought provoking
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