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Why and How to Implement Microservices on AWS

Andriy Stelmakh
September 11, 2023
10 mins to read

Table of Contents

    They say the old must make way for the new but not everything old is bad. But is that the case with legacy applications that hinder a business’s ability to innovate, pose security threats, and often slow down the overall performance? You probably know where we’re going with this, but let us continue. This article will go over ways to modernize legacy systems and cover the most widely used method – breaking down a monolith into microservices. We’ll describe AWS microservice architecture, its benefits, challenges, AWS portfolio of products, and finally some tips on how to implement microservices on AWS. Here is a short video about microservice architecture and key benefits of using it:

    The dangers of legacy systems

    Legacy applications are systems that are based on outdated technologies and could have been around in a company for ages. They can no longer be supported by the vendors, it becomes next to impossible to find specialists who could maintain them, maintenance costs eat up all the budget, and most importantly, such systems do not allow adding new features with ease or at all. According to a survey conducted by Accenture Research, 66% of C-level executives would like to replace all of their core legacy systems.

    It all can look scary enough for you to feel the urgent need to get rid of your legacy systems now, but we would stop you right there. Because not everything old is bad. Some parts of your legacy application could be kept unchanged, some could be reused or rewritten. It will save the budget and the nerves that come with the total replacement. Just remember that before deciding on how exactly you should deal with your legacy system, it is best to consult technical experts.
    Once we’ve established that we are avid supporters of legacy application modernization services, let us tell you the best way to do it.

    Legacy modernization statistics

    The best thing you can do with legacy apps without replacing them completely is to modernize them. And there are a variety of ways you can do it: encapsulate, rehost, re-platform, refactor, rearchitect, or rebuild. We’ve covered each of these approaches in detail in our blog post dedicated to legacy system modernization. For the purposes of this article, we would like to touch upon one widely used method in a majority of these approaches – adopting microservices-based architecture.

    And one of the best tools to use to implement microservices architecture is to do it on AWS. AWS (Amazon Web Services) is a favored option because it offers a variety of tools that can be seamlessly scaled and managed within the same ecosystem.

    This brings us to the next topic on our agenda, what are AWS microservices, anyway?

    What are AWS microservices?

    Microservice architecture, or simply microservices, is a cloud-native approach to building an application that it comprises many smaller services that are loosely coupled, independently deployable, and highly maintainable. Despite being developed and maintained separately from the other microservices, they all communicate over a combination of REST APIs or through events. Each unit is typically owned by independent development teams, which gives more flexibility to the result-oriented development process and makes such an app easier to scale.

    Microservices architecture

    Microservices architecture

    In contrast, monolithic applications are developed linearly as a single unit and are difficult to scale as they require vertical scaling. Why are they called ‘monolithic’? Because the source code for the entire app is built into a single deployment unit like .war or .ear. To scale a monolithic application, developers must increase the whole system’s capacity, disregarding which part of the system is experiencing the most load. Such solutions are self-contained entities.

    Many legacy systems were built with a monolithic approach, using a single code base for the whole application. Such an approach was proven to be less agile to innovations because with monolith one cannot introduce new features rapidly and stay on top of the market. To make any changes to the monolithic system, the whole system must be rebuilt and re-deployed to an updated version.

    Here’s a brief table with a comparison of monolithic and microservices architecture approaches:

    Use a single development stack for the whole systemDifferent stacks for each unit according to requirements
    Tightly coupled – changes to one component may affect othersLoosely coupled – changes to one component do not affect others
    Whole app needs to be redeployed with a small changeSelf-contained and hence, deployed independently
    Failure of one component can bring the entire system downFailure of one component does not bring the entire system down
    Scaling can often be a challengeOnly the busy component needs to be scaled
    Large team which can be difficult to manageEach service is built by a small team that can iterate faster
    A new developer has to grasp the logic of the whole applicationA new developer needs to understand only a particular microservice

    It comes as no surprise that business owners of monolithic legacy systems are taking a microservices approach. If you’d like to learn more about the pros and cons of using monolith or microservices architecture, read our article.

    AWS microservices characteristics

    Simply put, microservices development entails restructured teams and such architecture that is already prepared for failures, future scalability, and adding new features. Scaling or making incremental updates does not require a massive effort. We’ve gathered the most typical characteristics of microservices and described them below.

    Characteristics of AWS microservices architecture

    Characteristics Of AWS Microservices

    Benefits of using AWS microservices approach

    Due to containerization technology that allows separate software systems to function simultaneously in the same environment, and Docker that helps manage containers, microservices are the foundation for cloud-native applications. Containerization and the power of the cloud combined, offer numerous benefits for businesses that choose to implement microservices.

    Which AWS services are used with microservices?

    The Amazon Web Services portfolio provides a variety of easily integrated services, building blocks, and SDK packages that can help you build any microservice-based application regardless of scale and complexity. AWS cloud platform offers a selection of PaaS, IaaS, and SaaS solutions.

    Here are some of the building blocks from the vast AWS portfolio:

    What is a typical microservices architecture in AWS?

    Microservice architecture on AWS

    We’ll describe the main stages of app development using microservices below.

    User Interface

    The user interface (UI) is the appearance of display screens, pages, and visual elements like buttons or icons – everything that enables a person’s interaction with the device, product, or service. AWS provides the following services for delivering and storing the contents of the website:


    AWS offers powerful building blocks that help make microservices development easier:

    Data Store

    Each microservice should have its data persistence layer to be independently scaled. AWS offers a variety of stores that serve different purposes.

    How to create microservices using AWS

    We’ve covered the types of services offered in the AWS portfolio and now let’s talk about how you can begin implementing your microservices on AWS. We’ve put together a rough plan and some tips for you to get a general idea of where to start and what to keep in mind.

    Getting started

    Each microservice needs to have its own repository and its own CI/CD pipeline. For this, AWS CodeCommit can be used, as well as any other repository services like BitBucket, GitHub, or GitLab. AWS CodeBuild builds the code and CodeDeploy that automates software deployment can be used to produce a container – a deployable artifact (i.e. Docker image). Docker images are then pushed to AWS ECR (Docker registry).


    The type of microservices interaction depends on the project needs and its domain because microservices communicate differently with each other.

    Some services can expose REST WebAPI which can be called by different services. The other microservices (the whole system or some parts) can be event-based. In such cases, services can produce and react to events happening in other services.

    To achieve this, you can use an AWS SQS message broker. Event-based systems are easily scalable as there is no direct communication between services. All messages are processed by the message broker.


    Each service should have its own database which suits its needs. The database is selected according to the project needs and the type of function the microservice performs, which tasks. Some tasks cannot be performed with NoSQL databases and there are tasks not suitable for relational databases.

    AWS offers Aurora data storage among relational databases and DynamoDB among NoSQL ones. Using AWS Aurora or DynamoDB ensures your data is more available and more protected even in case something happens with the data center. Database technology should also be chosen considering what exactly your microservices are responsible for.

    Apart from the above-mentioned AWS services, depending on the microservice function we can use Load Balancers, Route53 for DNS Rooting, or S3 for file storage.

    Challenges in implementing microservices and how AWS can solve them

    What are the challenges with microservices? The microservices adoption journey is fraught with challenges and concerns for organizations. There are two types of challenges – technical and general. We will start with general and then review the most common technical problems and how AWS overcomes them.

    One of the most common challenges businesses face when adopting a microservices approach is the lack of experienced talent who can define which applications are the best candidates for transition to microservices. Uncertainty around security issues might also be a hurdle. According to a study conducted by IBM, 49% of surveyed IT executives noted insufficient internal expertise in DevOps or agile practices. 50% of them mentioned they are having difficulties integrating cloud and on-premises environments. All these concerns can be mitigated by bringing in the right technological partner.

    One of the most obvious technical challenges with microservices architectures is getting containerized services to discover and interact with each other. Amazon ECS comes to the rescue – it now includes integrated service discovery that enables services to easily discover and connect.

    During API implementation different versions of APIs need to have backward compatibility. After the API is published, the next challenges arise: managing, monitoring, and monetizing the ecosystem of third-party developers. The developers might also need to know how to throttle requests to protect the backend services, cache API responses, handle request and response transformation, and generate API definitions. AWS with its Amazon API Gateway solves these challenges and makes it easy to create and maintain RESTful APIs.

    As you can see, with skilled talent and carefully selected AWS offerings, the transition to microservices can be a painless and easy process.

    How we increased the airline’s website performance with AWS microservices architecture

    Europe’s largest airline approached us with a challenge – its primary website had a legacy architecture which was impeding the company’s business operations.

    To tackle this issue, we determined that implementing microservices through AWS was the optimal solution. We rebuilt the website’s architecture and migrated it from Adobe Experience Manager to AWS Cloud.

    With micro frontend architecture, we were able to deploy different parts of the application separately and quickly add third-party components. This change enabled our clients to conduct data-driven experiments, such as A/B testing, which helped them test services for purchasing tickets, booking accommodations, and renting cars.

    Through the implementation of AWS microservices architecture and a revamped UI/UX design, we achieved a 3x faster website performance. This improvement was reflected in the airline’s conversion and revenue rates.

    To conclude

    Making data-driven decisions has more efficiency than using your gut feeling for planning. The blossoming technology industry allows businesses to go above their expectations and gain a competitive advantage. To be on the safe side, and avoid the stress of changes, companies can resort to the reliable technical support of software development teams. Euristiq offers expertise in implementing solutions for automation and optimization of processes, establishing data pipelines, and as a result proper, real-time updated operational efficiency.


    What are AWS microservices?

    AWS microservices refer to the implementation of microservices architecture principles using the Amazon Web Services (AWS) platform. Applications that are built using the microservices approach are composed of small, independent, and loosely coupled services. AWS offers numerous services such as AWS Lambda, Amazon ECS, or AWS Fargate that help develop, deploy, and manage microservices, enabling app scalability, flexibility, and resilience.

    What are the characteristics of AWS microservices?

    AWS microservices have the same characteristics as other microservices, including independent component development, deployment, operation, and scaling. Through Amazon ECS and EKS, these services are self-sufficient, scalable, and containerized. They communicate using message queues or RESTful APIs, and distributed architecture and tools like Amazon CloudWatch ensure fault isolation and resilience. For streamlined deployment, AWS also provides managed services like AWS Lambda and API Gateway. Three common patterns have been identified when developing microservices on AWS: API-driven, event-driven, and data streaming.

    What are the 3 layers of microservices architecture?

    The three layers of a microservices architecture are the hardware layer, the communication layer, and the application platform.

    What are the 3 different microservices on AWS?

    The choice of building microservices on AWS opens a variety of AWS services that can be used. AWS Lambda, for example, allows running microservices without provisioning or managing servers, taking care of scaling, fault tolerance, and availability. Amazon Elastic Container Service (ECS) allows to run, manage, and scale containerized microservices using Docker containers. And Amazon Elastic Kubernetes Service (EKS) simplifies the deployment and management of containerized microservices using Kubernetes.

    How to build microservices using AWS?

    To create your microservices on AWS, first, determine the roles that each microservice will play before selecting the appropriate AWS services based on your requirements. Utilize the app containerization services, put communication, security, and user authentication in place, test each microservice separately and in combination with the rest of the system, and then set up monitoring and scaling. Establish continuous integration and continuous deployment (CI/CD) procedures and evaluate the effectiveness and performance of your microservices on a regular basis.

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