Cloud Native Applications: A Practical Guide

What Is a Cloud Native Application?

A cloud-native application is an application that has been designed and built specifically to run on cloud-based infrastructure. This means the application takes full advantage of the cloud computing model to increase speed, flexibility and quality while reducing deployment risks. Unlike traditional applications that are built to run on specific hardware in a specific data center, cloud-native applications are built to run anywhere.

Cloud-native applications are composed of small, independent and loosely coupled services called microservices. These microservices can be developed, deployed, and scaled independently, which gives you a level of agility and flexibility that is hard to achieve with traditional monolithic applications. Microservices are typically managed and deployed using cloud native technologies like containers or serverless functions.

In this article, you will learn:

Features of Cloud Native Applications
Cloud-Native vs. Cloud-Based Apps
Benefits of Cloud Native Applications
Cloud Native Infrastructure Flavors
Does Cloud Native Introduce a Cultural Change in Organizations?
Challenges of Cloud Native Apps
Best Practices for Cloud-Native Application Development

Features of Cloud Native Applications

A cloud native application is designed to run on a cloud native infrastructure platform with the following four key traits:

Cloud native applications are resilient. Resiliency is achieved when failures are treated as the norm rather than something to be avoided. The application takes advantage of the dynamic nature of the platform and should be able to recover from failure.
Cloud native applications are agile. Agility allows the application to be deployed quickly with short iterations. Often this requires applications to be written as microservices rather than monoliths, but having microservices is not a requirement for cloud native applications.
Cloud native applications are operable. An operable application is not only reliable from the end-user point of view, but also from the vantage of the operations team. Anperable software application is one that operates without needing application restarts or server reboots, or hacks and workarounds that are required to keep the software running.
Cloud native applications are observable. Observability provides answers to questions about application state. Operators and engineers should not need to make conjectures about what is going on in the application. Application logging and metrics are key to making this happen.

The above list suggests that cloud native applications impact the infrastructure that would be necessary to run such applications. Many responsibilities that have been traditionally handled by infrastructure have moved into the application realm.

Cloud-Native vs. Cloud-Based Apps

There is a key difference between cloud-native and cloud-based applications. While both types of applications are hosted on the cloud, they differ significantly in architecture, development methodology, and operational principles.

Cloud-based applications are traditional or legacy applications that have been moved to the cloud. They don’t take full advantage of the cloud’s capabilities because they were not initially designed for the cloud environment. They operate more like a tenant in a rented apartment, using the space but not leveraging the full potential of the infrastructure.

On the other hand, cloud-native applications are designed and built from the ground up to take full advantage of the cloud’s scalability, resilience, and flexibility. They use services and features that are available only in the cloud environment, such as auto scaling and self healing.

Benefits of Cloud Native Applications

Cost-Effective

With a cloud-native application, you can use the cloud provider’s infrastructure, and only pay for what you use. This means that you can start small and scale your application as the business grows, without significant upfront investments.

Moreover, the microservices architecture allows for more efficient resource utilization. Each service can be scaled independently, so you don’t waste resources on parts of your application that don’t need them. This can lead to significant cost savings in the long run.

Independently Scalable

In a traditional application, scaling usually involves investing in more powerful servers or adding more servers to your infrastructure. This can be expensive and time-consuming, and it often leads to overprovisioning, as you need to ensure that you have enough resources to handle peak loads.

In contrast, cloud-native applications are designed to be scalable from the ground up. Each microservice can be scaled independently, so you can allocate resources precisely where they’re needed. This means that you can handle peak loads without overprovisioning, and you can scale your application down when needed to conserve costs.

Easy to Manage

Traditional applications can be complex and difficult to manage, especially as they grow and evolve. You need to ensure that all components are working correctly, handle updates and patches, and deal with any issues that arise.

Cloud-native applications are designed to be easier to manage. Each microservice is a separate process, so you can update, patch, or troubleshoot it independently of the others. This makes management much simpler and less time-consuming. You can use orchestration platforms like Kubernetes to automate deployment, scaling, and management tasks.

Portability

Cloud-native applications are highly portable. This is because they are often platform-agnostic. You can run your application on any cloud provider’s infrastructure, or even move it between providers if necessary. This gives you a lot of flexibility. You’re not locked into a specific provider or platform, and you can take advantage of the best features and pricing from different providers.

Cloud Native Infrastructure Flavors

The ephemeral nature of the cloud demands automated development workflows that can be deployed and redeployed as needed. Cloud-native applications must be designed with infrastructure ambiguity in mind. This has led developers to rely on tools, like Docker, to provide a reliable platform to run their applications on without having to worry about the underlying resources. Influenced by Docker, developers have built applications with the microservices model, which enables highly focused, yet loosely coupled services that scale easily with demand.

Containerized Applications

Application containerization is a rapidly developing technology that is changing the way developers test and run application instances in the cloud.

The principal benefit of application containerization is that it provides a less resource-intensive alternative to running an application on a virtual machine. This is because application containers can share computational resources and memory without requiring a full operating system to underpin each application. Application containers house all the runtime components that are necessary to execute an application in an isolated environment, including files, libraries, and environment variables. With today’s available containerization technology, users can run multiple isolated applications in separate containers that access the same OS kernel.

Serverless Applications

In the cloud computing world, it is often the case that the cloud provider provides the infrastructure necessary to run the applications to the users. The cloud provider takes care of all the headaches of running the server, dynamically managing the resources of the machine, etc. It also provides auto scalability, which means the serverless applications can be scaled based on the execution load they are exposed to. All these are done so that the user can solely focus on writing the code and leave worrying about these tasks to the cloud provider.

Serverless applications, also known as Function-as-a-Service or FaaS, is an offering from most of the enterprise cloud providers in which they allow the users to only write code and the infrastructure behind the scenes is managed by them. Users can write multiple functions to implement business logic and then all these functions can be easily integrated to talk to each other. Such a system that involves the use of the above model is known as serverless architecture.

Does Cloud Native Introduce a Cultural Change in Organizations?

Cloud Native is more than a tool set. It is a full architecture, a philosophical approach for building applications that take full advantage of cloud computing. In this context, culture is how individuals in an organization interact, communicate, and work with each other.

In short, culture is the way your enterprise goes about creating and delivering your service or product. If you have the perfect set of cloud platform, tools, and techniques yet go about using them wrong—if you apply the right tools, only in the wrong culture—it’s simply not going to work. At best you’ll be functional but far from capturing the value that the system you’ve just built can deliver. At worst, that system simply won’t work at all.

The three major types of culture within enterprises are Waterfall, Agile, and Cloud Native. A quick primer:

Waterfall organizations are all about long-term planning. They deliver a large, solidly built and tested project bundling many separate services into one deployment every six months to one year (perhaps even longer) timeframe. They are risk-averse, with a long decision-making chain and rigid hierarchy. There are a lot of managers, including project managers. Waterfall organizations tend to have specialist teams handling very specific skills—security, testing, database administration, etc.

Agile organizations recognise the limitations imposed by monolithic long-term releases, and have adapted to deliver faster by using an iterative, feature-driven approach to releasing in two- to four-week ‘sprints’. Agile development breaks applications into their functional components, each of which is worked on, start to finish, by a single team.

Cloud Native organizations are built to take optimum advantage of functioning in cloud technologies (clouds will look quite different in the future, but we also build to anticipate this). Applications are built and deployed in a rapid cadence by small, dedicated feature teams made up of developers who also know how to build in networking, security, and all other necessities so all parts of the distributed system become part of the application.

Cultural awareness also grants the ability to start changing your organization from within, by a myriad of small steps all leading in the same direction. This allows you to evolve gradually and naturally alongside a rapidly changing world. ‘Long-term direction’ is literally the definition of strategy. So small steps towards this direction are strategic steps. Strategy is setting a long-term direction and taking steps on that direction.

Challenges of Cloud Native Apps

Below we cover a few challenges, which any organization should carefully consider before, and during, the move to cloud native.

Managing a CI/CD Pipeline for Microservices Applications

Microservices applications are composed of a large number of components, each of which could be managed by a separate team, and has its own development lifecycle. So instead of one CI/CD pipeline, like in a traditional monolithic app, in a microservices architecture there may be dozens or hundreds of pipelines.

This raises several challenges:

Low visibility over quality of changes being introduced to each pipeline
Limited ability to ensure each pipeline adheres to security and compliance requirements (see the following section)
No central control over all the pipelines
Duplication of infrastructure
Lack of consistency in CI/CD practices – for example, one pipeline may have automated UI testing, while others may not

To address these challenges, teams need to work together to align on a consistent, secure approach to CI/CD for each microservice. At the organizational level, there should be a centralized infrastructure that provides CI/CD services for each team, allowing customization for the specific requirements of each microservice.

Cloud Native Security Challenges

Cloud native applications present tremendous challenges for security and risk professionals:

A larger number of entities to secure

DevOps and infrastructure teams are leveraging microservices – using a combination of containers, Kubernetes and serverless functions – to run their cloud native applications. This growth is happening in conjunction with a constantly increasing cloud footprint. This combination leads to a larger number of entities to protect, both in production and across the application lifecycle.

Environments are constantly changing

Public and private cloud environments are constantly changing due to the rapid-release cycles employed by today’s development and DevOps teams. As enterprises deploy weekly or even daily, this presents a challenge for security personnel looking to gain control over these deployments without slowing down release velocity.

Architectures are diverse

Enterprises are using a wide-ranging combination of public and private clouds, cloud services and application architectures. Security teams are responsible for addressing this entire infrastructure and how any gaps impact visibility and security.

Networking is based on service identity

Unlike traditional applications that use a physical or virtual machine as a stable reference point or node of a network, in cloud native applications different components might run in different locations, be replicated multiple times, be taken down and then get spun up elsewhere. This requires a network security model that understands the application context, the identity of microservices and their networking requirements, and builds a zero trust model around those requirements.

Best Practices for Cloud-Native Application Development

Utilize Infrastructure as Code

Infrastructure as Code (IaC) is a method of managing and provisioning computing infrastructure through machine-readable definition files, rather than manual hardware configuration or interactive configuration tools. IaC is a key practice for cloud-native applications, as it allows for the automation of infrastructure setup, leading to faster and more reliable deployments.

With IaC, you can define your infrastructure in code files, version them like you would with application code, and keep them in source control. This allows for consistency across environments, as you can use the same scripts to set up your development, testing, and production environments. It also makes it easier to replicate your infrastructure, whether for scaling purposes or disaster recovery.

Furthermore, IaC supports the principles of immutable infrastructure, where servers are never modified after they’re deployed. If a change is required, a new server is created from a common image, and the old one is discarded. This approach reduces the inconsistencies and drifts that can occur over time, leading to more reliable and stable infrastructure.

Build Observability into Applications

Observability is crucial for maintaining the health and performance of cloud-native applications. To build observability into applications, it’s important to implement comprehensive logging, monitoring, and tracing. These elements work together to provide a holistic view of the application’s state and behavior:

Logging captures discrete events, such as errors or transactions.
Monitoring keeps track of metrics and trends over time.
Tracing connects the dots between various services, making it possible to follow the path of a request through microservices.

Design for Scalability and Fault Tolerance

Designing cloud-native applications for scalability and fault tolerance is fundamental to leveraging the full benefits of the cloud. Scalability ensures that the application can handle growth in workload by either scaling up (adding more resources to a single node) or scaling out (adding more nodes). Cloud-native design encourages the latter, utilizing the elasticity of the cloud to add or remove resources as needed.

Fault tolerance ensures that the application continues to operate correctly even when components fail. This can be achieved through strategies like redundancy, where multiple instances of a component are run, and the failure of one does not cause a system-wide failure, and graceful degradation, where non-critical functions can be temporarily disabled to keep the core operations running during a partial system failure.

Test Microservices Strategically

Testing microservices requires a strategic approach that accommodates their distributed nature and the independent lifecycle of each service. A robust testing strategy should include unit testing, integration testing, and end-to-end testing. Unit tests are crucial for ensuring that each microservice functions correctly in isolation. They are typically quick to run and can be integrated into the development process as part of a continuous integration pipeline.

Integration testing checks the interactions between microservices, ensuring that they communicate and function together as expected. This phase of testing can uncover issues in the interfaces and interaction patterns that might not be apparent in unit testing alone. End-to-end testing validates the entire system’s behavior and performance under a production-like scenario.

Learn More About Cloud Native Applications

Open Policy Agent: Authorization in a Cloud Native World

The Open Policy Agent (OPA) is a policy engine that automates and unifies the implementation of policies across IT environments, especially in cloud native applications. OPA was originally created by Styra, and has since been accepted by the Cloud Native Computing Foundation (CNCF). The OPA is offered for use under an open source license.

Learn about Open Policy Agent (OPA) and how you can use it to control authorization, admission, and other policies in cloud native environments, with a focus on K8s.