Agile, DevOps, and CI/CD are some of the commonly used terms in software development. Yet, they are often used incorrectly or even interchangeably. Each of these technical approaches and practices is aligned into each of them, but it is important to understand them individually as well as the differences between them, especially for newer developers.
Let’s start with individual definitions and explore what each practice entails.
Agile is an approach, a way to structure software development activities for the most effective results. It emphasizes incremental delivery of minimum viable products (MVPs), and a frequent feedback loop that gives teams data on what to improve. Once changes are implemented, the process is repeated until the software is cleared by Quality Assurance (QA) to be deployed to production.
Agile development is executed through iterative development of particular features in sprints that usually last 1-2 weeks. The barebones product is pushed to QA, tested, and sent back to teams for debugging and course correction. This is only possible through frequency, transparent and seamless collaboration and communication within and between teams. All members of all teams involved in a project have to be on the same page about timelines, business requirements and technical priorities for Agile development to succeed.
Agile is a philosophy that must be translated to real-world practice through certain frameworks. These frameworks, such as SCRUM and Lean, are operational blueprints that lay out a step-by-step game plan for how to undertake development activities.
Agile development stands on four fundamental precepts:
In a non-DevOps setup, developers create code, test it on their own systems, run it though QA and push it to Operations. Since Ops teams cannot afford to have too many changes on their system, new code is often incompatible. Now Ops sends the code back to developers who have to start from scratch, and the cycle continues. Because their roles are isolated from each other, there isn’t much communication about what is causing the code incompatibility.
DevOps focuses on removing this friction between development and operations teams, thus facilitating faster delivery without compromising on quality. DevOps eliminates the confinements of development and operations teams into silos. Instead of them throwing issues to each other and washing their hands off it. Instead, booth engineers and Ops personnel work in alignment across the entire software development lifecycle - from coding to testing to deployment.
Much like Agile, DevOps is also a philosophy of development that makes life easier for the entire team and the organization. DevOps also requires collaboration to succeed. Not just development and operations, but QA and security teams also usually need to integrate themselves into the pipeline to enable quick delivery of flawless software products.
The success of DevOps hinges on heavily incorporating automation into development processes. Automation tools help accomplish individual tasks (distinguishing code by multiple engineers, pushing code through predetermined test scenarios, etc.) This requires a tech stack that boils subsequent steps into a science and pushes code from one stage to another until it is ready to be released as a fully-functional, optimized application. Needless to say, they also help speed things up.
This is where Continuous Integration and Continuous Delivery (CI/CD) comes in.
Continuous Integration and Continuous Delivery (CI/CD) is a tangible implementation of DevOps principles. To meet the demands of the modern digital market, companies have to ship software at breakneck speed without missing out on a single aspect of quality and function.
In order to achieve this, developers and testers must use a CI/CD pipeline. It ensures the creation and release of software in a fast, secure and reliable way.
Let’s break down the terms.
CI or Continuous Integration is a practice in which developers push code to a shared repository at intervals, often several times a day. Each “push” is automatically verified, and in the absence of any errors, integrated with the master branch. Regular integration allows for small batches of code to be tested and debugged early on, so that they do not magnify in major issues in the latter stages of the development lifecycle.
CD or Continuous Delivery ensures that the code is always deploy-ready. That includes all changes - new features, bug fixes, changes in configuration, etc. This is achieved by virtue of CI which pushes code, tests it, and merges it to the master branch automatically. This is accomplished no matter how many time code is integrated in a day, even if it numbers in the thousands. The intent here is to always have a deploy-ready, bug-free product that has passed through requisite tests.
CD sometimes also refers to Continuous Deployment. In this practice, once all changes are tested and integrated with the main codebase, the software is automatically deployed into production. In Continuous Delivery, deployment requires supervision and approval by one or more human personnel - QA, business or technical managers. Continuous Deployment eliminates the final step of human intervention.
Like Agile Development and DevOps, CI/CD requires the right tools, frameworks and skilled personnel to succeed and provide the desired technical and commercial results.