Definition of DevOps

DevOps is a new term emerging from the collision of two major related trends. The first was also called “agile system administration” or “agile operations”; it sprang from applying newer Agile and Lean approaches to operations work.  The second is a much expanded understanding of the value of collaboration between development and operations staff throughout all stages of the development lifecycle when creating and operating a service, and how important operations has become in our increasingly service-oriented world (cf. Operations: The New Secret Sauce).

One definition Jez Humble explained to me is that DevOps is “a cross-disciplinary community of practice dedicated to the study of building, evolving and operating rapidly-changing resilient systems at scale.”

That’s good and meaty, but it may be a little too esoteric and specific to Internet startup types. I believe that you can define DevOps more practically as 

DevOps is the practice of operations and development engineers participating together in the entire service lifecycle, from design through the development process to production support.

A primary corollary to this is that part of the major change in practice from previous methods is

DevOps is also characterized by operations staff making use many of the same techniques as developers for their systems work.

Those techniques can range from using source control to testing to participating in an Agile development process.

For this purpose, “DevOps” doesn’t differentiate between different sysadmin sub-disciplines – “Ops” is a blanket term for systems engineers, system administrators, operations staff, release engineers, DBAs, network engineers, security professionals, and various other subdisciplines and job titles. “Dev” is used as shorthand for developers in particular, but really in practice it is even wider and means “all the people involved in developing the product,” which can include Product, QA, and other kinds of disciplines.

DevOps has strong affinities with Agile and Lean approaches. The old view of operations tended towards the “Dev” side being the “makers” and the “Ops” side being the “people that deal with the creation after its birth” – the realization of the harm that has been done in the industry of those two being treated as siloed concerns is the core driver behind DevOps. In this way, DevOps can be interpreted as an outgrowth of Agile – agile software development prescribes close collaboration of customers, product management, developers, and (sometimes) QA to fill in the gaps and rapidly iterate towards a better product – DevOps says “yes, but service delivery and how the app and systems interact are a fundamental part of the value proposition to the client as well, and so the product team needs to include those concerns as a top level item.” From this perspective, DevOps is simply extending Agile principles beyond the boundaries of “the code” to the entire delivered service.

In the end, DevOps is a little tricky to define, just like its older brother Agile. But it’s worth doing. When left at the pure philosophy level, both can seem like empty mom-and-apple-pie statements, subject to the criticism “You’re just telling me ‘do my job better,’ duh…” But conversely, just the practices without the higher level guidance turn into a cargo cult. “I do what this Scrum book says so I’m doing Agile” is as erroneous as “I’m using Chef so I’m DevOps right?” To be a successful Agile or DevOps practitioner is to understand all the layers that go into it, and what a given DevOps implementation might contain or not contain. In the end, what DevOps hopes to bring to Agile is the understanding and practice that software isn’t done until it’s successfully delivered to a user and meets their expectations around availability, performance, and pace of change.