Comparing DevOps vs. Agile vs. Waterfall methodologies
DevOps, Agile and Waterfall offer distinct approaches to software delivery, varying in speed, flexibility, risk management and suitability based on project needs and goals.
Software development and delivery are far more complex than they once were. At one time, software delivery was mostly about delivering software on time and without bugs. Today, however, software delivery methods are directly tied to factors such as business agility, operational risk, speed to market, compliance and more.
As such, DevOps, Agile and Waterfall delivery approaches have become much more than just development frameworks. Instead, an organization's approach to development is carefully chosen based on the framework's ability to deliver business value.
What is DevOps?
The word DevOps is a mashup of the words development and operations. As its name suggests, DevOps focuses on integrating the development and operations environments. This integration means that there's now shared responsibility for system stability, with developers and IT admins both playing a role. DevOps is geared toward creating short feedback loops, resulting in very frequent release cycles.
DevOps pros
The main advantage of DevOps is that it enables extremely fast software release cycles, resulting in faster time to market. When business opportunities arise, DevOps positions organizations to capitalize on them quickly.
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What is DevOps? Meaning, methodology and guide
Adopting DevOps also forces improved collaboration between developers and IT operations staff. Additionally, DevOps relies heavily on IT automation and monitoring, which collectively improve scalability while also reducing errors.
DevOps cons
Despite its many benefits, there are some disadvantages to using DevOps. One such disadvantage is that it requires the organization's culture to change, which might require costly company reorganization. Similarly, the organization will likely have to invest in DevOps tools and infrastructure.
Another disadvantage is that DevOps can be tough to implement in regulated industries. This same difficulty can also arise in nonregulated organizations that have implemented strict governance plans.
Finally, DevOps only works if the organization has robust monitoring, security and incident response processes in place. Otherwise, DevOps can introduce operational risks.
What is Agile?
Agile breaks large projects into small, incremental projects called sprints. The development cycles are intentionally kept short, and priorities are frequently reassessed. Following each of these reassessments, the development teams work to incorporate feedback and adjust the code to meet any new requirements.
Agile pros
The main advantage of Agile development is that it enables software to adjust to changing business requirements quickly. Agile depends on continuous stakeholder feedback, which inevitably means the final product will be very well aligned with business needs.
Another advantage is that because Agile development focuses on very small, incremental releases, there is almost no risk of large project failures. Instead, problems are addressed early, leading to a better overall outcome. There is almost no risk that the final product will require major revisions, as the ongoing revision process has allowed the software to evolve throughout development.
Agile cons
There are, of course, some disadvantages to using the Agile development method. For starters, because frequent revisions are expected, it becomes more difficult to predict the project's final cost and delivery date.
Perhaps the biggest disadvantage to Agile development is that it opens the door to scope creep. Unless management teams remain disciplined, there is a good chance that revision requests will quickly escalate to the point of becoming unreasonable.
Finally, for Agile development to succeed, stakeholders must remain engaged throughout the project. A stakeholder who begins to lose interest or who doesn't work through review processes quickly enough can derail the entire project schedule.
What is Waterfall?
Waterfall is a more traditional development process designed to be linear. Specifically, projects are broken into phases, such as defining requirements, designing functionality, development, testing and deployment. Each step must be completed before the next step begins.
Waterfall pros
The main advantage of Waterfall development is that the project scope is very clear, and project milestones are easy to define. Waterfall is also easy to implement, as it doesn't require any corporate reorganization or have stakeholders spend massive amounts of time in endless meetings or reviewing code. Likewise, Waterfall coding simplifies project tracking and accountability, and it's a good fit for projects whose scope isn't expected to change before completion.
Waterfall cons
The biggest downside to Waterfall development is that it can be problematic when a project's scope changes before the project is completed. Also, because review processes tend to occur late in the development pipeline, there is a very real risk that the code developed doesn't perfectly align with stakeholders' requirements, leading to unexpected and costly revisions.
DevOps vs. Agile vs. Waterfall: Key differences
DevOps, Agile, and Waterfall differ in many ways, including their delivery approaches. Waterfall is geared toward linear and phased software delivery, while Agile is iterative and incremental. DevOps focuses on continuous delivery.
Delivery speed also varies by method. Waterfall is slow, but predictable. Agile is moderately fast, but the nonstop review cycles can slow down development. DevOps is specifically designed to deliver software as quickly as possible.
How the development processes manage risks also differ. Waterfall seeks to manage risks through extensive upfront planning. Agile reduces risks through its many review cycles, while DevOps uses automation, monitoring and rapid rollbacks to reduce them.
The development methods also vary widely across organizations. Waterfall is hierarchical and requires minimal involvement from those outside the development team. Agile is highly collaborative and requires a major time commitment from stakeholders. DevOps involves shared ownership between development and operations teams.
When to use Waterfall vs. Agile vs. DevOps
Waterfall tends to work best when the project requirements are clearly defined and are unlikely to change. It's also a good fit when regulatory requirements need to be considered or when stakeholders need predictable budgets and schedules.
Agile works best when requirements are uncertain and the whole project is driven by customer feedback. Agile is also a good option for building digital products or externally facing applications, or when organizations want to prioritize innovation.
DevOps is best suited to organizations that prioritize frequent release cycles. It tends to work best in cloud or microservices environments. DevOps is a good fit only when development and operations teams can collaborate closely.
Which methodology is best?
Unfortunately, there is no one-size-fits-all answer to the question of which methodology is best. A model that works well in one organization might be a poor fit for another. As such, organizations should consider which approach best aligns with their needs and structure, based on factors such as the regulatory environment, team size and structure, infrastructure complexity, desired release frequency and risk tolerance.
Conclusion
DevOps, Agile and Waterfall represent three completely different philosophies for software development. Each of these approaches has its own strengths and weaknesses. Organizations must choose the development method that strikes the best balance of speed, predictability, governance and control.
Rather than making a decision dogmatically, it's important to consider the organization's size, structure, technology stack and risk tolerance. It's also worth noting that Waterfall, DevOps and Agile aren't the only options. Organizations are increasingly adopting hybrid approaches that capitalize on the best parts of the three methods.
Editor's note: An editor used AI tools to aid in the generation of the comparison chart. Our expert editors always review and edit content before publishing.
Brien Posey is a former 22-time Microsoft MVP and a commercial astronaut candidate. In his more than 30 years in IT, he has served as a lead network engineer for the U.S. Department of Defense and a network administrator for some of the largest insurance companies in America.
