A Deeper Look into Microservices & Hexagonal Architecture

In the previous part of this blog, we looked at how microservices architecture has changed modern products. Let us deep dive into the technologies and how these are crucial for microservices.

Microservices allow modular decomposition strategies to navigate the challenges of managing data and transactional contexts in distributed systems while also increasing developmental and go-to-market agility. 

Trends like microservices have influenced how products are now being built and tested by major software development firms. Microservices allow easier software evolution by creating the right boundaries at the team and component level and keeping them in the right order even as the software continues to evolve. 

Methodologies like Hexagonal architecture (Domain Driven Development-DDD) are further maturing microservices. Apart from this, Containers and Orchestration Frameworks are also becoming essential for microservices.

How Does Hexagonal Architecture (Domain Driven Development-DDD) Fuel Microservices Architecture?

Domain-Driven Design was introduced by Eric Evans in 2003 as a software engineering approach that keeps the Domain at the center of the core software set. In Domain-Driven Design, the whole solution revolves around the business rules and related terminologies. 

Hexagonal architecture is an architecture model that allows designing software applications around domain logic to isolate it from external factors. The DDD principles can be translated into an architectural design, becoming an excellent approach for microservices. Each microservice is bound by context and, as such, must be built into the bounded context. 

With microservices, however, there can be some trade-offs. Architecture decisions in microservices, for example, can lead to complexities for reliability and performance. Microservices also have their own internal architecture to account for which is not the case with the monolithic architecture.

How Microservices Architecture Changed Modern Products?

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Ensuring there are no logic leaks and a clear separation of boundaries becomes crucial. This is important, especially when external factors, such as the user interface and the database, are interchangeable with similar components that would, in equivalent ways, interact with an application. Keeping the application-agnostic external actors becomes vital to avoid logic leaks between business logic and external components. 

A hexagonal architecture further fine-tunes microservices. At the core of this architecture lies the domain model, formed by employing the building blocks of tactical DDD. The domain model is where the business logic lives, and all business decisions are made. In a hexagonal architecture, the application layer and the domain layer are quite the same, while the UI and the infrastructure layer are treated very differently. 

Hexagonal architecture (Domain Driven Development-DDD) fuels Microservices Architecture by ensuring that the businesses and software speak the same language. It allows the use of ubiquitous language and access to domain logic. Additionally, it fuels the Microservices Architecture by enabling:

• Domain analysis and Domain model creation
• Ensuring that use cases do not impact the Domain
• Bounded context definition
• Definite entities, aggregates, and services
• Identification of exact microservices that need to leverage this architecture for optimal performance

The hexagonal architecture keeps the focus on the Domain implementation and ensures that teams do not worry over technical detail too soon.

How Containers and Orchestration Frameworks Are Essential for Microservices Architecture (Kubernetes, Docker Swarm, or Apache Mesos)
The microservices framework creates a massive, scalable, and distributed system that prevents bottlenecks of a central database and improves business capabilities. It enables the continuous delivery and deployment of multiple types of application software and allows organizations to modernize their technology stack with ease. 

Microservices are deployed using VMs or Containers. Containers have emerged as the favored deployment route for microservices since they are lighter, portable, and modular. A container is a bundling of an application and all its dependencies which makes it easier to deploy irrespective of the environment. These dependencies consist of all libraries, binaries, and configuration files needed to run the application.

Kubernetes, Docker Swarm, or Apache Mesos are some of the most commonly used container management systems that solve the problem of how to ensure that the software runs reliably when moved from one computing environment to another.

Orchestration platforms also become essential to microservices as the latter see increased adoption. Orchestration frameworks make it easier to create complex processes in products that are using microservices. This is especially true when automating a complex business process. 

A product can involve several microservices simultaneously when automating a complex business process. The orchestration frameworks manage the process execution and ensure that no data is lost in this process while making it easier for developers to manage system development. It is also easier to get support to fix emerging problems. 

Containers and orchestration frameworks become essential to microservices since these:

• Build a convenient environment that shows microservices interactions clearly
• Support asynchronous activities and workflows and make performance more stable 
• Enable better and more even load balancing across the infrastructure to achieve seamless microservices scalability by scaling the containers and balancing the load up or down
• Regulate the redundancy and availability of containers for better application availability 
• Distribute resource allocation between containers for better performance and stability 
• Improve load balancing of service discovery between containers
• Monitor the overall health of the architecture and application with ease

Parting Thoughts

Containers and container orchestration frameworks are essential for microservices for simplicity, agility, and speed. These also allow enterprises to deploy and manage the same application across different environments without any redesign. It is easier to orchestrate services, including storage, networking, and security, with microservices in containers.

Containers and orchestration frameworks deliver an ideal application deployment unit and self-contained execution environment. Running multiple parts of an app independently in microservices on the same hardware becomes much easier. It also provides greater control over individual application pieces and life cycles.