|Software development process|
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DevOps (a clipped compound of "software DEVelopment" and "information technology OPerationS") is a term used to refer to a set of practices that emphasize the collaboration and communication of both software developers and information technology (IT) professionals while automating the process of software delivery and infrastructure changes. It aims at establishing a culture and environment, where building, testing, and releasing software can happen rapidly, frequently, and more reliably.
- 1 Overview
- 2 Etymology
- 3 DevOps toolchain
- 4 Relationship to agile and continuous delivery
- 5 Goals
- 6 Cultural change
- 7 Deployment
- 8 DevOps and architecture
- 9 Scope of adoption
- 10 References
- 11 Further reading
In traditional, functionally-separated organizations, there is rarely a cross-departmental integration of these functions with IT operations. But DevOps promotes a set of processes and methods for thinking about communication and collaboration—between departments of development, QA (quality assurance), and IT operations.
At the Agile 2008 conference, Andrew Clay Shafer and Patrick Debois discussed "Agile Infrastructure". The term DevOps was popularized through a series of "devopsdays" starting in 2009 in Belgium. Since then, there have been devopsdays conferences, held in many countries, worldwide.
Because DevOps is a cultural shift and collaboration (between development, operations and testing), there is no single "DevOps tool": it is rather a set (or "DevOps toolchain"), consisting of multiple tools. Generally, DevOps tools fit into one or more of these categories, which is reflective of the software development and delivery process:
- Code — Code development and review, version control tools, code merging;
- Build — Continuous integration tools, build status;
- Test — Test and results determine performance;
- Package — Artifact repository, application pre-deployment staging;
- Release — Change management, release approvals, release automation;
- Configure — Infrastructure configuration and management, Infrastructure–as–Code tools;
- Monitor — Applications performance monitoring, end–user experience.
Though there are many tools available, certain categories of them are essential in the DevOps toolchain setup for use in an organization. Some attempts to identify those basic tools can be found in the existing literature.
Tools such as Docker (containerization), Jenkins (continuous integration), Puppet (Infrastructure-as-Code) and Vagrant (virtualization platform)—among many others—are often used and frequently referenced in DevOps tooling discussions.
Relationship to agile and continuous delivery
Agile and DevOps are similar, but, while agile software development represents a change in thinking and practice (that should lead to organizational change), DevOps places more emphasis on implementing organizational change to achieve its goals.
One goal of DevOps is to establish an environment where releasing more reliable applications, faster and more frequently, can occur. Release managers are beginning to utilize tools (such as application release automation and continuous integration tools) to help advance this goal—doing so through the continuous delivery approach.
Continuous delivery and DevOps are similar in their meanings (and are, often, conflated), but they are two different concepts:
- DevOps has a broader scope, and centers around:
- Continuous delivery, on the other hand, is an approach to automate the delivery aspect, and focuses on:
- Bringing together different processes;
- Executing them more quickly and more frequently.
They have common end goals and are often used in conjunction, to achieve them. DevOps and continuous delivery share a background in agile methods and lean thinking: small and quick changes with focused value to the end customer. They are well communicated and collaborated internally, thus helping achieve quick time to market, with reduced risks.
The specific goals of DevOps span the entire delivery pipeline. They include improved deployment frequency, which can lead to:
- Faster time to market;
- Lower failure rate of new releases;
- Shortened lead time between fixes;
- Faster mean time to recovery (in the event of a new release crashing or otherwise disabling the current system).
Simple processes become increasingly programmable and dynamic, using a DevOps approach. DevOps aims to maximize the predictability, efficiency, security, and maintainability of operational processes. Very often, automation supports this objective.
DevOps integration targets product delivery, continuous testing, quality testing, feature development, and maintenance releases in order to improve reliability and security and provide faster development and deployment cycles. Many of the ideas (and people) involved in DevOps came from the enterprise systems management and agile software development movements.
DevOps aids in software application release management for an organization, by standardizing development environments. Events can be more easily tracked, as well as resolving documented process control and granular reporting issues. The DevOps approach grants developers more control of the environment, giving infrastructure more application-centric understanding.
Benefits of DevOps
Companies, that practice DevOps, have reported significant benefits, including: significantly shorter time to market, improved customer satisfaction, better product quality, more reliable releases, improved productivity and efficiency, and the increased ability to build the right product by fast experimentation.
DevOps is more than just a tool or a process change; it inherently requires an organizational culture shift. This cultural change is especially difficult, because of the conflicting nature of departmental roles:
- Operations — seeks organizational stability;
- Developers — seek change;
- Testers — seek risk reduction.
Getting these groups to work cohesively — is a critical challenge, in enterprise DevOps adoption.
Building a DevOps culture
DevOps principles demand strong interdepartmental communication—team-building and other employee engagement activities are often used—to create an environment that fosters this communication and cultural change, within an organization. Team–building activities can include board games, trust activities, and employee engagement seminars.
Companies with very frequent releases may require a DevOps awareness or orientation program. For example, the company that operates the image hosting website Flickr developed a DevOps approach, to support a business requirement of ten deployments per day; this daily deployment cycle would be much higher at organizations producing multi-focus or multi-function applications. This is referred to as continuous deployment or continuous delivery  and has been associated with the lean startup methodology. Working groups, professional associations and blogs have formed on the topic since 2009.
DevOps and architecture
To practice DevOps effectively, software applications have to meet a set of architecturally significant requirements (ASRs; such as: deployability, modifiability, testability, and monitorability). These ASRs require a high priority and cannot be traded off lightly.
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. Because the size of each service is small, it allows the architecture of an individual service to emerge through continuous refactoring, hence reduces the need for a big up front design and allows for releasing the software early and continuously.
Scope of adoption
Some articles in the DevOps literature assume, or recommend, significant participation in DevOps initiatives from outside an organization's IT Department, e.g.: "DevOps is just the Agile principle, taken to the full enterprise." An example of such broader participation is this recommended change to internal funding processes: "Funding is, typically, provided in a waterfall manner: with specific hard dates (months, quarters, fiscal year) and gates, not suitable for a Continuous Delivery model. Funding too should be continuous."
Adoption of DevOps is being driven by many factors — including:
- Use of agile and other development processes and methods;
- Demand for an increased rate of production releases — from application and business unit stakeholders;
- Wide availability of virtualized and cloud infrastructure — from internal and external providers;
- Increased usage of data center automation and configuration management tools;
- Increased focus on test automation and continuous integration methods;
- A critical mass of publicly–available best practices.
The theory of constraints applies to the adaptation of DevOps: the single constraint is the inherent aversion to change, from departments, within the enterprise. Incremental adoption embodies the methodology the "Theory of Constraints" provides for combating any constraint, known as “The five focusing steps”.
The incremental approach centers around the idea of minimizing risk and cost of a DevOps adoption whilst building the necessary in-house skillset and momentum needed to have widespread successful implementation across the enterprise. Gene Kim’s "Three Ways Principles" essentially establishes different ways of incremental DevOps adoption:
The first way: systems thinking
The emphasis is on the performance of the entire system, as opposed to the performance of a specific or single department or individual. Focus is also on all business value streams that are enabled by IT. This process works in a linear fashion, ensuring that defects are never passed along.
The second way: amplify feedback loops
The emphasis is on increasing feedback and understanding of all teams involved. The outcomes of this will be: increased communication and responding to all customers (internal and external), shortening and amplifying all feedback loops, and embedding knowledge where and to whom it’s needed.
The third way: culture of continual experimentation and learning
Two things are equally important: experimentation and practice. Embedding this in the working culture—where learning from taking risks, and repetition and practice are encouraged—is key to mastery. Risk taking and experimentation—promoting improvement and mastery—provides the skills, required to revert any mistakes.
- Loukides, Mike (2012-06-07). "What is DevOps?".
- Floris, Erich; Chintan, Amrit; Maya, Daneva (2014-12-10). "A Mapping Study on Cooperation between Information System Development and Operations".
- Samovskiy, Dmitriy (2010-03-02). "The Rise of DevOps". Fubaredness Is Contagious.
- Kim, Gene. "DevOps Culture Part 1".
- Lyman, Jay. "DevOps mixing dev, ops, agile, cloud, open source and business". 451 CAOS Theory.
- Turnbull, James (Feb 2010). "What DevOps means to me...". Kartar.
- Debois, Patrick. "Agile 2008 Toronto". Just Enough Documented Information. Retrieved 12 March 2015.
- Debois, Patrick (2009). "DevOpsDays Ghent". DevopsDays. Retrieved 31 March 2011.
- Debois, Patrick. "DevOps Days". DevOps Days. Retrieved 31 March 2011.
- Gartner Market Trends: DevOps – Not a Market, but Tool-Centric Philosophy That supports a Continuous Delivery Value Chain (Report). Gartner. 18 February 2015.
- Edwards, Damon. "Integrating DevOps tools into a Service Delivery Platform". dev2ops.org.
- Seroter, Richard. "Exploring the ENTIRE DevOps Toolchain for (Cloud) Teams". infoq.com.
- Theakanath, Thomas. "DevOps Stack on a Shoestring Budget". devops.com.
- "Stronger DevOps Culture with Puppet and Vagrant". Puppet Labs. Retrieved 2015-10-22.
- Ambler, Scott W. (12 February 2014). "We need more Agile IT Now!". Dr. Dobb’s The world of software Development. San Francisco: UBM.
- Best Practices in Change, Configuration and Release Management (Report). Gartner. 14 July 2010.
- Hammond, Jeffrey (9 September 2011). "The Relationship between DevOps and Continuous Deliver". Forrester Research. Forester.
- Humble, Jez; Farley, David (2011). Continuous Delivery: reliable software releases through build, test, and deployment automation. Pearson Education Inc. ISBN 978-0-321-60191-9.
- "What is DevOps?". NewRelic.com. Retrieved 2014-10-21.
- Nasrat, Paul. "Agile Infrastructure". InfoQ. Retrieved 31 March 2011.
- Wadhera, Anila (June 6, 2016). "10 Key DevOps Practices to Improve IT Efficiency". TO THE NEW. Retrieved September 2, 2016.
- Chen, Lianping (2015). "Continuous Delivery: Huge Benefits, but Challenges Too". IEEE Software. 32 (2): 50. doi:10.1109/MS.2015.27.
- Emerging Technology Analysis: DevOps a Culture Shift, Not a Technology (Report). Gartner.
- Loukides, Mike (11 June 2012). What is Devops?. Oreilly Media.
- "Gartner IT Glossary – devops". Gartner. Retrieved October 30, 2015.
- Walls, Mandi (15 April 2013). "Building a DevOps Culture". OReilly Media.
- Roach, Patrick. "Dice Breakers: Using DevOps principles and nerdery to reimagine Team building". DevOps.com.
- "10+ Deploys Per Day: Dev and Ops Cooperation at Flickr".
- "SAM SIG: Applied Lean Startup Ideas: Continuous Deployment at kaChing". SVForum.
- Humble, Jez. "Why Enterprises Must Adopt Devops to Enable Continuous Delivery". Cutter IT Journal.
- "Applied Lean Startup Ideas: Continuous Deployment at kaChing".
- "DevOps Days 2009 Conference".
- Edwards, Damon. "DevOps Meetup Recap".
- Chen, Lianping (2015). Towards Architecting for Continuous Delivery. The 12th Working IEEE/IFIP Conference on Software Architecture(WICSA 2015). Montréal, Canada: IEEE.
- Balalaie, A.; Heydarnoori, A.; Jamshidi, P. (2016-05-01). "Microservices Architecture Enables DevOps: Migration to a Cloud-Native Architecture". IEEE Software. 33 (3): 42–52. doi:10.1109/MS.2016.64. ISSN 0740-7459.
- Chen, Lianping; Ali Babar, Muhammad (2014). Towards an Evidence-Based Understanding of Emergence of Architecture through Continuous Refactoring in Agile Software Development. The 11th Working IEEE/IFIP Conference on Software Architecture(WICSA 2014). IEEE.
- "DevOps is Agile for the Rest of the Company". DevOps.com.
- "The Art of DevOps". DevOps.com.
- "Virtual Infrastructure products: features comparison". Welcome to IT 2.0: Next Generation IT infrastructures.
- Ellard, Jennifer. "Bringing Order to Chaos through Data Center Automation". Information Management. SourceMedia.
- "Impact of DevOps on Testing". DevOps.com.
- "Theory of Constraints". vorne Industries Inc. Retrieved 13 November 2015.
- Bhargava, Rajat (27 March 2014). "DevOps Adoption – Startups". DevOps.com.
- Kim, Gene (22 January 2013). "DevOps distilled, Part 1: The three underlying principles" (PDF). IBM DeveloperWorks.
- "Incremental DevOps" (PDF).
- Kim, Gene. "The Three Ways: The Principles Underpinning DevOps". IT Revolution Press. Retrieved 13 November 2015.