DevOps is the combination of application development and operations, which minimizes or eliminates the disconnect between software developers who build applications and systems administrators who keep infrastructure running.
When the Agile methodology is properly used to develop software, a new bottleneck often appears during the frequent deployment and operations phases. New updates and fixes are produced so fast in each sprint that infrastructure teams can be overwhelmed with deployments and push back on the pace of delivery. To allievate some of these issues, application developers are asked to work closely with operations folks to automate the delivery of code from development to production.
DevOps: Python tools to get started is a presentation slideshow that explains that while DevOps is a culture, it can be supported by tools such as Fabric, Jenkins, BuildBot and Git which when used properly can enable continuous software delivery.
A look at DevOps tools landscape provides an introductory overview of the tooling that is typically required to perform DevOps. The tools range from source control systems, continuous integration, containers to orchestration. For an Atlassian-centric perspective on tooling, take a look at this post on how to choose the right DevOps tools which is biased towards their tools but still has some good insight such as using automated testing to provide immediate awareness of defects that require fixing.
DevOps vs. Platform Engineering considers DevOps an ad hoc approach to developing software while building a platform is a strict contract. I see this as "DevOps is a process", while a "platform is code". Running code is better than any organizational process.
So, you've been paged provides their development team's "Communicate -> Learn -> Act" structure for handling production issues based on lessons learned from their years of experience dealing with incidents.
Operations for software developers for beginners gives advice to developers who have never done operations work and been on call for outages before in their career. The advantage of DevOps is greater ownership for developers who built the applications running in production. The disadvantage of course is the greater ownership also leads to much greater responsibility when something breaks!
Why are we racing to DevOps? is a very high level summary of the benefits of DevOps to IT organizations. It's not specific to Python and doesn't dive into the details, but it's a decent start for figuring out why IT organizations consider DevOps the hot new topic after adopting an Agile development methodology.
SRE vs. DevOps: competing standards or close friends? covers Google's take on how Site Reliability Engineering (SRE) fits with the DevOps world. Roughly speaking, SRE is more closely aligned with metrics and how to operate infrastructure and applications, rather than the broader principles embodied by the DevOps philosophy.