OpenStack’s Test Driven Core > it’s where I think “what is core” discussions are heading


core lighthouse

In helping drive OpenStack’s “what is core” dialog, I’ve had the privilege of listening to a lot of viewpoints about what we are and should be.  Throughout the process, I’ve tried to put aside my positions and be an objective listener.  In this post, I’m expressing where I think this effort will lead us.

If OpenStack culture values implementation over API then our core definition should too.

How do we make a core definition that values implementation over API?  I think that our definition should also be based on what’s working in the field over qualitative definitional statements.  The challenge in defining core is to find a way to reinforce this culture in a quantifiable way.

The path forward lies in concrete decomposition (and not because you were talked to death on the sidewalk).

Concrete decomposition means breaking Core into small units for discussion like “is provisioning a single server critical?”  More importantly, we can use tests as the unit for decomposition.  Tests are gold when it comes to defining expected OpenStack behaviors.  In our tests, we have a description of which use-cases have been implemented.  Discussing those use-cases is much more finite than arguing over stable versus innovative development methodologies.

I believe that we are moving toward community tests playing an essential role in OpenStack.  As a believer in the value of BDD and CI, I think that placing high value on tests improves the project in fundamental ways beyond defining Core.  It creates a commercial motivation for contributors to add tests, inches us toward interoperability, and helps drive stability for users.  In these ways, using tests to measure OpenStack drives the right behaviors for the project.

Another consequence I anticipate is a new role for the User Committee (UC).  With a growing body of tests, the OpenStack Foundation needs a way to figure out the subset of tests which are required.  While the Technical Committee (TC) should demand a comprehensive suite of tests for all projects, they lack the perspective to figure out which use-cases are being implemented by our user base.  Gathering that data is already the domain of the UC so asking them to match implemented use-cases to tests seems like a natural extension of their role.

By having data supporting the elevation of tests to must-pass status, I envision a definition of Core that is based on how OpenStack is implemented.  That, in turn, will help drive our broader interoperability objectives.

Agile takes discipline: having a strategy means saying “no” more than saying “yes”

With the Crowbar release behind us, it’s time for my team at Dell to do some Capital “P” Planning. Planning for us includes both tactical (next release) and strategic (the releases beyond the one after next), but each type of planning looks very different. I’m going to call it “roadmapping” because planning means something specific and tactical in Agile.

I love roadmapping but I’m a pain to roadmap with because I’m a ruthless prioritizer.

When I sit down for roadmapping, I always do it from a 1 to N list without ties. That means that when marketing asks for a new feature (double the foo on the bar!) we put it on the list relative to other work that needs to get done. If you add something at the top then something else will fall off the bottom. Effectively, we’re using the list to say no to a lot of great ideas. This is essential because “the great is the enemy of the good (Voltaire).” It’s hard, but that’s the cold reality of delivering product.

The most important part of strategy is figuring out what to push down to make room for the precious few yes items.

Successful roadmapping is negotiating the splitting of big ideas into smaller ones. Decomposition is a circular process because one compromise may require another, but one change may force a cascading assumption fault. If you get too emotionally committed to one feature or subset then you’re going to slow down the process. It’s vital to approach roadmapping in free fall.

As always, my advice is to not mix meeting objectives. If you need more strategy then you’ve got to make time for it.

Interested in more…stay tuned for Agile Tao: balancing tactics & strategy