DevOps is a set of practices that combines

software development Software development is the process of conceiving, specifying, designing, programming, documenting, testing, and bug fixing involved in creating and maintaining applications, frameworks, or other software components. Software development inv ...

(''Dev'') and IT operations (''Ops''). It aims to shorten the systems development life cycle and provide

continuous delivery Continuous delivery (CD) is a software engineering approach in which teams produce software in short cycles, ensuring that the software can be reliably released at any time and, following a pipeline through a "production-like environment", witho ...

with high software quality. DevOps is complementary to

agile software development In software development, agile (sometimes written Agile) practices include requirements discovery and solutions improvement through the collaborative effort of self-organizing and cross-functional teams with their customer(s)/ end user(s), ...

; several DevOps aspects came from the ''agile'' way of working.

Definition

Other than it being a cross-functional combination (and a

portmanteau A portmanteau word, or portmanteau (, ) is a blend of wordsLen Bass, Ingo Weber, and

Liming Zhu Liming may refer to: Processes * Liming (soil), the application of alkali to soil to neutralize soil acidity. * Liming (leather processing), process where hides are soaked in an alkali solution to create parchment or leather * The use of birdl ...

—three computer science researchers from the CSIRO and the

Software Engineering Institute The Software Engineering Institute (SEI) is an American research and development center headquartered in Pittsburgh, Pennsylvania. Its activities cover cybersecurity, software assurance, software engineering and acquisition, and component capab ...

—suggested defining DevOps as "a set of practices intended to reduce the time between committing a change to a system and the change being placed into normal production, while ensuring high quality". However, the term is used in multiple contexts. At its most successful, DevOps is a combination of specific practices, culture change, and tools.

History

In 1993 the Telecommunications Information Networking Architecture Consortium ( TINA-C) defined a Model of a Service Lifecycle that combined software development with (telecom) service operations. In 2009, the first conference named devopsdays was held in

Ghent Ghent ( nl, Gent ; french: Gand ; traditional English: Gaunt) is a city and a Municipalities of Belgium, municipality in the Flemish Region of Belgium. It is the capital and largest city of the East Flanders province, and the third largest i ...

Belgium Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to ...

. The conference was founded by Belgian consultant, project manager and agile practitioner Patrick Debois. The conference has now spread to other countries. In 2012, the State of DevOps report was conceived and launched by Alanna Brown at Puppet. As of 2014, the annual State of DevOps report was published by Nicole Forsgren, Gene Kim, Jez Humble and others. They stated that the adoption of DevOps was accelerating. Also in 2014, Lisa Crispin and Janet Gregory wrote the book More Agile Testing, containing a chapter on testing and DevOps. In 2016 the DORA metrics for throughput (deployment frequency, lead time for changes), and stability (mean time to recover, change failure rate) were published in the State of DevOps report.

Relationship to other approaches

Many of the ideas fundamental to DevOps practices are inspired by, or mirror, other well known practices such as Lean and Deming's

Plan-Do-Check-Act PDCA (plan–do–check–act or plan–do–check–adjust) is an iterative design and management method used in business for the control and continual improvement of processes and products. It is also known as the Shewhart cycle, or the control ...

cycle, through to The Toyota Way and the

Agile Agile may refer to: * Agile, an entity that possesses agility Project management * Agile software development, a development method * Agile construction, iterative and incremental construction method * Agile learning, the application of incremen ...

approach of breaking down components and batch sizes. Contrary to the "top-down" proscriptive approach and rigid framework of ITIL in the 1990s, DevOps is "bottom-up" and a flexible practice, created by software engineers, with software engineer needs in mind.

Agile

The motivations for what has become modern DevOps and several standard DevOps practices such as automated build and test, continuous integration, and

originated in the Agile world, which dates (informally) to the 1990s, and formally to 2001. Agile development teams using methods such as extreme programming couldn't "satisfy the customer through early and continuous delivery of valuable software" unless they subsumed the operations / infrastructure responsibilities associated with their applications, many of which they automated. Because Scrum emerged as the dominant Agile framework in the early 2000s and it omitted the engineering practices that were part of many Agile teams, the movement to automate operations / infrastructure functions splintered from Agile and expanded into what has become modern DevOps. Today, DevOps focuses on the deployment of developed software, whether it is developed using Agile oriented methodologies or other methodologies.

ArchOps

ArchOps presents an extension for DevOps practice, starting from software architecture artifacts, instead of source code, for operation deployment. ArchOps states that architectural models are first-class entities in software development, deployment, and operations.

CI/CD

Automation is a core principle for achieving DevOps success and CI/CD is a critical component. Plus, improved collaboration and communication between and within teams helps achieve faster time to market, with reduced risks.

Site-reliability engineering

In 2003,

Google Google LLC () is an American Multinational corporation, multinational technology company focusing on Search Engine, search engine technology, online advertising, cloud computing, software, computer software, quantum computing, e-commerce, ar ...

developed site reliability engineering (SRE), an approach for releasing new features continuously into large-scale high-availability systems while maintaining high-quality end-user experience. While SRE predates the development of DevOps, they are generally viewed as being related to each other.

Toyota production system, lean thinking, kaizen

Toyota production system, also known under the acronym TPS, was the inspiration for

lean thinking Lean thinking is a management framework made up of a philosophy, practices and principles which aim to help practitioners improve efficiency and the quality of work. Lean thinking encourages whole organisation participation. The goal is to organis ...

with its focus on continuous improvement, kaizen, flow and small batches. The andon cord principle to create fast feedback, swarm and solve problems stems from TPS.

DevSecOps, shifting security left

DevSecOps is an augmentation of DevOps to allow for security practices to be integrated into the DevOps approach. Contrary to a traditional centralized security team model, each delivery team is empowered to factor in the correct security controls into their software delivery. Security practices and testing are performed earlier in the development lifecycle, hence the term "shift left" can be used. Security is tested in three main areas: static, software composition, and dynamic. Checking the code statically via static application security testing (SAST) is white-box testing with special focus on security. Depending on the programming language, different tools are needed to do such static code analysis. The software composition is analyzed, especially libraries and their versions are checked against vulnerability lists published by CERT and other expert groups. When giving software to clients, licenses and its match to the one of the software distributed are in focus, especially

copyleft Copyleft is the legal technique of granting certain freedoms over copies of copyrighted works with the requirement that the same rights be preserved in derivative works. In this sense, ''freedoms'' refers to the use of the work for any purpose, ...

licenses. Dynamic testing is also called black-box testing. The software is tested without knowing its inner functions. In DevSecOps it is on one hand called dynamically (DAST), or penetration testing. The goal is to catch, amongst others, errors like cross-site scripting, or SQL injection early. Threat types are for example published by the

open web application security project The Open Web Application Security Project (OWASP) is an online community that produces freely-available articles, methodologies, documentation, tools, and technologies in the field of web application security. The OWASP provides free and open ...

, e.g. its TOP10. On the other hand, especially with microservices interactive application testing (IAST) is helpful to check which code is executed when running automated functional tests, the focus is to detect vulnerabilities within the applications. Contrary to SAST and DAST, IAST works inside the application. DevSecOps has also been described as a cultural shift involving a holistic approach to producing secure software by integrating security education, secure by design, and security automation.

Cultural change

DevOps initiatives can create cultural changes in companies by transforming the way

operations Operation or Operations may refer to: Arts, entertainment and media * ''Operation'' (game), a battery-operated board game that challenges dexterity * Operation (music), a term used in musical set theory * ''Operations'' (magazine), Multi-Man ...

, developers, and testers collaborate during the development and delivery processes. Getting these groups to work cohesively is a critical challenge in enterprise DevOps adoption. DevOps is as much about culture, as it is about the toolchain.

Microservices

Although in principle it is possible to practice DevOps with any architectural style, the microservices architectural style is becoming the standard for building continuously deployed systems. Small size service allows the architecture of an individual service to emerge through continuous refactoring.

DevOps automation

It also supports consistency, reliability, and efficiency within the organization, and is usually enabled by a shared code repository or version control. As DevOps researcher Ravi Teja Yarlagadda hypothesizes, "Through DevOps, there is an assumption that all functions can be carried out, controlled, and managed in a central place using a simple code."

Automation with version control

Many organizations use version control to power DevOps automation technologies like virtual machines, containerization (or OS-level virtualization), and

CI/CD In software engineering, CI/CD or CICD is the combined practices of continuous integration (CI) and (more often) continuous delivery or (less often) continuous deployment (CD). Comparison * Continuous integration: Frequent merging of severa ...

. The paper "DevOps: development of a toolchain in the banking domain" notes that with teams of developers working on the same project, "All developers need to make changes to the same codebase and sometimes edit even the same files. For efficient working, there has to be a system that helps engineers avoid conflicts and retain the codebase history," with the Git version control system and the GitHub platform referenced as examples.

GitOps

GitOps evolved from DevOps. The specific state of deployment configuration is

version-control In software engineering, version control (also known as revision control, source control, or source code management) is a class of systems responsible for managing changes to computer programs, documents, large web sites, or other collections ...

led. Because the most popular

is Git, GitOps approach has been named after Git. Changes to configuration can be managed using code review practices, and can be rolled back using version-controlling.