The Chef site starts out with, “Chef is a systems integration framework, built to bring the benefits of configuration management to your entire infrastructure.” There is an important point hidden in that description; Chef is not a CM tool. Of course it can be used as one, and many do, but from its beginning it has been leveraged by others such as Engine Yard inside of their own infrastructure. You can safely bet it will be an integral part of the Opscode platform when released as well.
While I was off dealing with my startup’s acquisition this fall, a chef user wrote knife. It was a command line client for interacting with a chef server. An impressively simple prototype, made possible and powered by the chef libraries and API. This has happened before with chef; for instance a while ago in the 0.6 era, an OS X GUI client called Casserole was written by another chef user with an itch to scratch. However, something has happened with knife that is interesting enough I’d like to specifically point out; it got mainlined and heavily expanded.
This happened for a handful of reasons. For one, it was simply a great idea. The kind of user who would be attracted to chef as a tool is very likely to be a power user who would rather not spend their time clicking around a graphical interface. It’s much easier to script a command line tool where needed, passing data in and out for quick hacks to your infrastructure. The folks at Opscode saw this, agreed, and set out to add full functionality to it for the upcoming 0.8 release.
What I think is most important is the planning a full API from the start. From hearing Adam talk about other tools being “first-class citizens” in chef-land, and knowing his experience writing iClassify as an early open source external node tool for puppet, I know this design was intentional. Using iClassify to tell puppet about your nodes was great, but puppet assumed that you only wanted this tool to classify nodes in the way puppet thought about nodes. Consequentially, when you wanted to to use data in iClassify about your nodes to make decisions about your infrastructure on the fly, you were forced to do it in templates. This created the expected repetition of loading the iClassify library and accessing iClassify in many templates, but also required you at times to do some fancy footwork to get data between templates when you really wanted puppet to know about the data itself.
Reductive Labs recently announced a dashboard for puppet. I was hoping this meant those barriers had been removed. It certainly creates really nice graphs from your puppet report data. However from the README it looks like you’re still pushing limited data into puppet using the external node interface. Reductive is going to have to expand this interface greatly if dashboard is to have any meaningful node integration benefits that we didn’t already have two years ago with iClassify.
Just as you can see some concepts from other configuration management tools in chef, you can see parts of iClassify. It was a great start and it was disappointing that the puppet community didn’t engage it further. Perhaps it was simply before its time, but I believe it was that there were too few doors into puppet-land to let you really take advantage of and grow external tools.
I think this was the lesson that Opscode learned, and consequently chef was born with an API. With it we can accomplish nearly anything we dream up. What is most exciting about this is that we can do whatever everyone else dreams up. I can’t wait to see what that is.