This article is based on concepts originally published at TechTarget.com and expands on the core ideas around applying DevOps principles to application modernization.
What Is Application Modernization in a DevOps Context?
A “modern” application, in DevOps terms, is not simply one built with the latest frameworks or languages. It is an application designed—or adapted—to support the core DevOps values of speed, reliability, collaboration, and continuous improvement. Application modernization the DevOps way means reshaping how your app is built, delivered, and operated so that it aligns with these values, even if the underlying business logic has existed for years.
Defining DevOps Principles
Before you can modernize an application with DevOps in mind, you need a clear understanding of what DevOps principles actually are.
DevOps is an approach to software development and delivery that breaks down the traditional silos between development, QA, security, and IT operations teams. Its core goals are:
- Faster software delivery through automation and streamlined workflows
- Greater reliability through consistent, repeatable processes and testing
- Improved collaboration by aligning teams around shared goals and tooling
- Agility and scalability so that the application and the team can respond quickly to change
When you modernize an application according to these principles, you are not just updating code—you are rethinking how the application is structured, deployed, and maintained.
You Don’t Have to Start from Scratch
One of the most important insights for teams approaching modernization is that legacy applications do not necessarily need to be thrown away and rebuilt from the ground up. DevOps principles are flexible enough to be applied incrementally. The right modernization strategy depends on your application’s current architecture, your team’s capabilities, and your business objectives.
Key Questions to Guide Your Modernization Approach
1. Should You Rebuild or Refactor?
A full rebuild—recreating an application from scratch—is sometimes necessary, but it is rarely the first option you should reach for. In many cases, refactoring is the better path. Refactoring means modifying the internal structure of the application to support modern DevOps practices without changing its external behavior.
A common refactoring strategy is decomposing a monolithic application into microservices. Rather than deploying the entire application as a single unit, you break it into smaller, independently deployable services. This makes individual components easier to test, deploy, and scale. You may need to rewrite specific modules, but a complete rewrite is rarely warranted.
2. What Tools Best Support Your Delivery Pipeline?
Modern delivery tooling can unlock significant efficiency gains for existing applications. Docker containers, for example, are a practical option for many legacy apps. The general process involves writing a Dockerfile that describes your application’s dependencies and runtime environment, building a container image, and running the application as a container.
Containerizing an application can provide meaningful advantages over traditional virtual machine hosting, including faster startup times, more consistent environments across development and production, and simplified horizontal scaling. That said, the complexity of the migration varies depending on how tightly your application is coupled to specific OS configurations or libraries.
3. How Can You Align Your Teams Around Delivery?
DevOps is as much an organizational change as a technical one. If your development, QA, security, and operations teams work in isolation from one another, modernizing the application’s code alone will not deliver the full benefits of DevOps.
Review your current workflow and identify handoff points where work stalls or information is lost between teams. Restructure those workflows so that teams collaborate continuously throughout the development and delivery process. Shared tooling, common dashboards, and joint on-call responsibilities are practical mechanisms for increasing cross-team alignment.
4. How Can You Maximize Scalability and Agility?
A DevOps-friendly application should not be tightly coupled to a specific infrastructure platform. If your application can only run on a particular operating system version, hardware configuration, or on-premises environment, your ability to scale and adapt is limited.
Common strategies to increase portability and scalability include:
- Migrating to a cloud platform, which enables on-demand scaling and reduces infrastructure management overhead
- Containerizing the application using Docker or a similar tool, so it can run on any host with the container runtime installed
- Externalizing configuration so that environment-specific settings (database URLs, API keys, feature flags) are injected at runtime rather than baked into the application
5. How Can You Implement Continuous Delivery?
Continuous delivery (CD) means that every change to the application—whether a bug fix, a new feature, or a configuration update—can be released to production reliably and quickly. This requires both process changes and technical infrastructure.
To build a continuous delivery pipeline for an existing application:
- Automate your build and test processes so that every code change is validated without manual intervention
- Use a CI/CD platform (such as Jenkins, GitLab CI, GitHub Actions, or CircleCI) to orchestrate the pipeline from commit to deployment
- Ensure that all teams involved in delivery—development, QA, and ops—have visibility into the pipeline and shared ownership of release quality
- Instrument your production environment with monitoring and alerting so that issues can be detected and rolled back quickly
There Is No Single Path to Modernization
The right modernization approach for your application depends on its current state, your team’s skills, your business constraints, and your target architecture. A microservices decomposition might be the right move for one application and an over-engineered distraction for another. Containerization might unlock major efficiency gains in one environment and add unnecessary complexity in another.
This flexibility is a defining characteristic of DevOps: there is no single prescribed methodology. Instead, DevOps offers a set of principles and practices that teams can apply pragmatically based on their specific context. The goal is not to follow a checklist but to continuously improve the speed, quality, and reliability of software delivery.
Start by assessing where your biggest bottlenecks are—in team collaboration, deployment frequency, infrastructure flexibility, or testing coverage—and apply the DevOps practices most likely to address those constraints first.