Alot has been written about DevOps. Let me try to give my perspective on it, based on my experience over the last 2.5 years. Prior to that, I hardly even heard of it, but I learned alot with the team that I joined, where they had this 'thing' - this way of working - that seemed immature and cowboy to my overly corprate-ised planned way of working. Now I realise that this DevOps way, seemingly haphazard and erratic, actually worked like a well oil machine to Get Things Done!
Lets start off with what DevOps is not! You cant buy it, or implement it.
Start off by reading this work and talks given by Adam, the founder of Chef. I was lucky to attend his talk in 2015, when the banks arranged him to come down to SA.
DevOps happens when you put skilled guys - Developer and Operations (SysAdmin) people - next to each other, break down all the corporate rules around they must work, and they will naturally work towards DevOps. Reporting lines is not the same as lines of communication, so even if they are part of different teams, they will work better together, in order to get stuff done.
So these two guys, sitting next to each other (or not, because if they on Slack or Telegram, it wont make a difference), will know enough about each others work, to work together. As Adam puts it, they are not generalists (where they equally well versed in networking, hardware, development, OS and all layers in the stack), rather, they are well connected specialists, each with their own expertise in the stack, but they care enough, and know enough about each others work, to jump over the silos, and avoid the gaps between each others systems, so things flow seamlessly between them.
Corporate mentality is the anti-thesis of DevOp - overcome with their Silos, yet the Corporates desperaly want DevOps, because they envious of why everyone else gets things done. Read this for a laugh
So primarily, DevOps is a culture, a mindset, a way of working. Once you have that in place, then you enable it with automation tools.
This is probably the best source of info - The Agile Admin