In the world of software development, there was a time when the primary focus was on functional requirements - making sure that the software did what it was supposed to do. Extensive testing, meticulous code reviews, and exhaustive validation processes were put in place to ensure that every feature and function worked flawlessly. And we got really good at it. Functional requirements became the cornerstone of our development processes, and for a good reason - they defined what the software was meant to achieve.

However, the landscape of software development has evolved significantly in recent years, with the rise of cloud-native applications and services. As these applications become increasingly complex, the focus has shifted from merely delivering functional features to ensuring the robustness and reliability of the underlying infrastructure. This paradigm shift underscores the critical importance of verifying non-functional aspects in the development cycle.

While functional requirements are still crucial, they are no longer the sole determinants of success. In today’s complex, highly distributed, and multi-tenanted cloud environments, verifying functional requirements is just the tip of the iceberg. What’s become abundantly clear is that it’s the non-functional requirements, such as performance, scalability, security, and resilience, that have taken center stage in the development cycle. In this blog, we’ll explore the importance of verifying and testing cloud reliability for mission-critical applications, focusing on strategies to ensure uninterrupted service, even in complex, dynamic cloud environments.

Verifying and Testing Cloud Reliability

In this context, the non-functional requirements of an application—particularly performance, scalability, and reliability—have taken center stage. Continuous validation has emerged as the practice that underlines the importance of meticulously verifying these key non-functional aspects from the inception of a project.

Continuous validation, as the name suggests, is not a one-time endeavor but an ongoing, iterative process that integrates validation into every phase of software development. The aim is simple yet paramount: to ensure that your application delivers optimal performance, scales seamlessly to meet growing demands, and maintains unwavering reliability, even in the face of unexpected challenges. This practice recognizes that the most critical non-functional attributes—performance, scalability, and reliability—cannot be left to chance or addressed as an afterthought.

The imperatives are clear: your application must perform seamlessly, whether it’s under a light load or experiencing a deluge of user traffic. It must scale effortlessly, accommodating surges in demand without breaking a sweat. And perhaps most crucially, it must exhibit unwavering reliability, with the ability to recover gracefully from failures, outages, or unforeseen disruptions.

But how can these lofty goals be achieved in practice? The answer lies in a fundamental shift: moving testing and validation to the forefront of the development process. This ‘shift-left’ approach ensures that performance, scalability, and reliability are not just ‘nice-to-haves’ tacked onto the end of a project but core elements integrated into every stage of development.

Continuous validation

The initial step in the continuous validation process is comprehensive planning. This involves identifying the critical scenarios, dependencies, expected usage patterns, and the specific performance and scalability targets that the application should meet. To ensure that these targets are clearly defined and measurable, it’s essential to establish a set of threshold values. These threshold values act as benchmarks to quantify the expected performance of key scenarios within the application. For instance, the expected number of user logins, requests per second for a particular API, or operations per second for background processes can all serve as relevant examples of such thresholds.

After careful planning and defining measurable threshold values, the second crucial step in continuous validation centers around the actual implementation of the validation process.

  1. Performance Validation: In this phase, the objective is to rigorously assess the application’s performance under various scenarios. Performance tests, including load testing, stress testing, and latency testing, are executed to evaluate how well the application performs under anticipated workloads and to ensure that it meets the predefined performance benchmarks. The goal is to uncover performance bottlenecks, identify areas for improvement, and confirm that the application delivers the desired level of responsiveness.

  2. Scalability Validation: Scalability, a key non-functional requirement, is validated through a series of tests aimed at assessing the application’s ability to scale seamlessly. These tests involve gradually increasing the load or concurrent users to verify that the application can handle growing demands while maintaining optimal performance. Scalability testing provides insights into how the application behaves as it grows, ensuring that it can expand to meet the evolving requirements without degradation in performance.

  3. Reliability Validation: Reliability is a core attribute that ensures the application’s ability to function without interruptions. In this phase, reliability tests assess the application’s robustness, fault tolerance, and recovery mechanisms. These tests may include failover and disaster recovery scenarios to validate that the application can continue to operate reliably even when faced with unexpected failures or outages.

Continuing the journey of continuous validation, the next step is to put the meticulous planning and threshold values into action through practical implementation. This phase is where the rubber meets the road, and your application’s non-functional attributes—performance, scalability, and reliability—are put to the test in real-world scenarios. To illustrate this step, see CraftedSpecially which showcases the use of powerful tools such as Azure Load Testing and Azure Chaos Studio. These tools, when utilized effectively, can be instrumental in conducting performance, scalability, and reliability validation. They enable the creation of realistic testing environments and scenarios that closely mirror real-world usage, offering insights into your application’s capabilities and highlighting areas for improvement.

The final step in the continuous validation journey is where the true resilience of your application is forged. If, during the testing and validation phases, it’s discovered that the non-functional requirements fall short of the defined benchmarks, it’s crucial to embrace a cycle of improvement and verification. This means that any deficiencies should be addressed, and necessary enhancements must be implemented. This iterative process can involve code optimizations, architectural changes, or the introduction of new technologies and strategies. Once these improvements are made, the validation process restarts, and the application is subjected to rigorous testing once more. This continual cycle ensures that your application evolves to not only meet but consistently exceed its non-functional requirements, and that the pursuit of excellence remains an ongoing commitment.


To ensure the effective testing and validation, it is imperative that these processes become an integrated and inseparable part of the overall development lifecycle. Integration begins with incorporating these non-functional tests into the Continuous Integration/Continuous Deployment (CI/CD) pipeline. By doing so, you enable the seamless and automated execution of these tests at each phase of development, from code changes to deployment.

Integrating non-functional testing into the CI/CD pipeline means that every code commit, build, and deployment is subject to rigorous scrutiny against these key performance parameters. This approach not only identifies issues early in the development process but also ensures that your application consistently meets its non-functional requirements as it evolves. The result is a more resilient, high-performing, and scalable application that can thrive in the dynamic and unpredictable cloud environment, delivering an exceptional user experience and maintaining optimal reliability.

Stragegies for Continuous Validation

Indeed, it’s essential to acknowledge that continuous validation may not be a one-size-fits-all approach for every application in your portfolio. While it is a powerful strategy for enhancing non-functional attributes like performance, scalability, and reliability, it is particularly vital for applications that bear high availability requirements, typically of 99.99% or “four nines” uptime and beyond. These applications, often serving mission-critical functions or handling sensitive data, cannot afford to compromise on performance or reliability.

Therefore, organizations should judiciously allocate resources and focus their continuous validation efforts on applications where the stakes are highest. By doing so, you ensure that the investments in time, tools, and processes are in alignment with the critical nature of the application, safeguarding not only its performance but also your reputation and user trust. For less critical applications, a risk-based approach might be more appropriate, allowing you to tailor the level of validation to the specific needs and expectations of each application. Ultimately, the goal is to strike a balance between the rigor of continuous validation and the individual requirements and constraints of each application within your portfolio.

As we conclude our exploration of continuous validation, it’s clear that this practice is pivotal in our pursuit of cloud-native excellence. By setting the right benchmarks, automating non-functional tests, enhancing resilience, and fostering a culture of collaboration, we equip ourselves with the tools and mindset required to build and maintain applications that consistently meet the demands of performance, scalability, and reliability. In the dynamic realm of cloud-native applications, continuous validation is not just a strategy; it’s our guiding principle toward the zenith of excellence.