The Complete Guide to Microservices

Special contributor to Scout APM  on February 04, 2021

Microservices, also known as microservices architecture, refers to a method of designing and developing software systems. Microservice architecture is becoming increasingly popular as developers create larger and more advanced apps. The goal is to help enterprises become more Agile, especially as they adopt a culture of continuous testing.

Here are the basic features of microservices:

Microservices are popular among executives, developers, and IT project managers. This is because a microservice architecture accurately reflects the way businesses like to run their teams and development processes. Let's discuss an example to see how this is true. IT departments deploy components independently in a microservices setup that communicates over a combination of REST, message brokers, and event streaming. What's more, creating an app out of smaller services is easier and affordable. Smaller modules go through a continuous delivery and testing process, making it hassle-free to debug and test apps. This improves one’s ability to deliver error-free apps and ultimately, great customer experiences.

Not to mention how easy it is to optimize resources with a microservices setup. Different teams focus on independent services, allowing your business to deploy more quickly. It becomes simple to pivot when necessary, and you minimize development time, making code more reusable.

Microservices encourages companies to embrace a true DevOps culture and work in competitive, cross-functional teams. This makes every employee responsible for service provisioning instead of only concentrating on feature and functionality. Also, microservices requires everyone to be at their best and accept the fact that testing is not necessarily always straightforward. Each service comes with its own dependencies that increase in number as new features appear. Furthermore, with continuous development and delivery, your team should be ready to instantly provision resources to capitalize on the benefits of microservices. This means equipping yourself for quick provisioning and app development. 

In any case, microservices consist of feature-rich services and protocols while providing increased modularity. The end goal is to simplify the process of developing, testing, and deploying apps, without forgetting to change and maintain them when need be. With large and complex software projects broken down into smaller and more manageable modules, developers benefit from a decentralized approach to building software. From a technical viewpoint, this simplifies daily workloads and contributes to productivity gains in the long run. 

You can mix and match microservices, and experiment with new ones as your business evolves. It becomes easier to accomplish your goals faster, innovate, and invest in DevOps practices to automate in this world of digital transformation. All these factors make microservices architecture a perfect arrangement that translates into greater ROI with reduced TCO.

Next, we'll talk about the basics of microservice architecture before deep-diving into what they are.

The Basics of Microservice Architecture

To understand the anatomy of a microservice architecture, let’s assess the human body first. It combines various systems, whereby a significant percentage of them are independent parts but work together. Also, each body system has a unique function that it performs. The remaining organs feature several frameworks that help to form a fully functional body. Now, this is the same concept that microservice architecture uses, but under the software system field.

From a technical perspective, a microservice system makes it easy to develop function modules that work as one. These single software modules are why organizations increase cost efficiency, performance, and agility. Not to mention that these single software modules promote continuous and early delivery to accelerate time to market.

How can you achieve microservice architecture perfection, and what are the basic microservice architecture principles? Which practices promote the ideal microservice architecture design? Here are the basics you need to know:

Basics for a Successful Microservice Architecture Design

Functionality Scope

It is pivotal to define the microservice architecture scope because of concurrent development implementation and rollout by various individuals to support unique product functionality. Most people do not promote several tiny microservice architecture developments, but research shows that these microservices feature several elements.

Here, the microservice architecture scope points to the features associated with one software module. It becomes easy to develop a single software module because the microservice architecture can function almost similar to a stateless system. Therefore, this explains the need for noting the functions a microservice architecture performs. 

By understanding what a microservice architecture does, it becomes easy to identify its capabilities. This allows you to prevent overload and know the perfect business scenarios that require this software.

For example, a monolithic setup calls a single code several times. In this case, you access and use the code easily if you create a microservice architecture. By minimizing the number of occasions you call the code, you will avoid bloated services and improve efficiency.

The question is: how to define the microservice architecture scope? There is no one rule to explain the microservice design, but you can refer to some practices or guidelines to define this term. Follow these steps to define microservice architecture design.

Step One

Identify the codes replicated under different software modules. Identify the number of times these codes appear under the modules. Also, note the effort you put in to set up each code in various software modules. If a 'high' answer appears, then the microservice architecture design scope, in this case, involves handling the codes that appear more than once.

Step Two

Check if the software module depends on other software modules to perform its function. In general, you should check if there is a loose coupling between the software module and the other services. If yes, then the microservice architecture scope, in this case, is the entire software module scope.

Step Three

Finally, you can define the microservice architecture scope by checking if the microservice features efficiently run a heavy load. This process tells you if you must scale up the microservice architecture after using it for a specific period. If yes, let the scalable bits be the microservice architecture scope instead of combining this scope with microservice features.

High Cohesion and Loose Coupling Combination

Microservice architecture focuses primarily on ensuring that services perform their functions independently. Hence, it becomes easy to edit, update, or roll out a different microservice with microservice architecture without disrupting other available services. However, you can only achieve this if services share low interdependence. In this case, a loosely coupled software system defines a situation where a service does not know anything or has fewer ideas about other microservices.

Always combine related functionalities when creating small components from a monolithic architecture. Cohesion means combining these related logics into one unit. The best microservice architecture is the one featuring a higher cohesion. A low cohesion suggests the services communicate frequently, resulting in a poorly performing software system.

Unique Identification Source

A service should be the identification source for the remaining part of the software system. For example, a user receives an order identification after placing an order on an eCommerce site. This identification features all the information relating to the order.

From the microservice side, the order identification remains the only source containing the order's details. If another service requests further information relating to the order service, then the order identification will serve as the information source and not the actual attributes.

API Integration

Dividing the monolithic architecture into several services suggests these services harmonize and perform their functions together to create a software system.

Ask yourself: how does communication between these services take place? What if you use several technologies to develop various services? Can there be any relation between these services?

The answer is yes. These services relate because they use an Application Programming Interface. Leveraging the right application programming interface is vital for microservice architecture design. It keeps the communication flow between the client and service calls. However, businesses require straightforward API execution and hassle-free transition to ensure proper functioning.

The business domain is another pivotal element to consider when making an application programming interface. It simplifies the process of differentiating the functions each service performs.

Also, the system has several external clients that can be other users or different applications. There is an adapter that handles the called business logic. This adapter returns the business logic request and changes the database. 

Data Storage Segregation

Any data kept for a particular service should remain private for that specific service. Hence, it is only that particular service capable of accessing the data. However, other services can access that service by using an application programming interface.

This feature keeps the data safe and prevents it from 'service coupling.' It is crucial to classify data depending on the users. You can achieve this by using data storage segregation or Command and Query Responsibility Segregation.

Traffic Management

The traffic going through services will differ after setting up the application programming interfaces and putting the system into use. Here, traffic refers to calls that users deliver to particular services.

Usually, services will run slowly, causing call delays. Also, calls are likely to overload services. These two cases will affect service performance, resulting in hardware and software crashes.

There is a need to manage this high traffic. You can experience smooth traffic flow by introducing specific ways for calling and receiving calls. With this method, services can easily eliminate issues that affect system performance and cause delays.

The 'Auto-scaling' process is one way through which you can eliminate these issues. This process involves tracking the services and taking immediate actions where necessary. You should also include a ''circuit breaker pattern'' that plays an integral role in supplying incomplete data in the case of an unresponsive service or broken call.

Process Automation

Microservices with independent designs should function without relying on other services. The automation process promotes self-deployment and allows microservices to work without any interference.

Moreover, the automation process promotes the microservices cloud-native nature and their ability to work in all environments. However, DevOps must achieve this feature and work towards service evolution.

Minimal Database Tables

Reaching database tables to accumulate data can be a challenging process because it needs dedicated time and energy. The point is to focus primarily on the business function and not the database. Also, prioritize business functions during the microservice design process. You can attain this by ensuring the microservice architecture design features minimal database tables.

Constant Monitoring

You must allocate time and resources to demolish a monolithic architecture and transform it into a microservice architecture design. It can be challenging to track the changes that the traditional tools make.

You are likely to increase the microservice performance by inserting data caching and data layers. However, these features will make it harder to track the entire process. So, it is vital to create a process that can actively monitor data storage in a centralized location. This will help you design a high-performing microservice architecture.

Besides this, the microservice architecture monitoring devices will track each service, combine the data, and keep it in the central location. Ensure you follow this step as you follow the microservices architecture design principles.

To successfully design a microservice, note how the application programming interface plays an integral role. Equip yourself with a process that can track the application programming interface performance. This tracking process ensures that microservice architecture functionality remains high in terms of overall performance, responsiveness, and speed.

Microservices vs. Monolithic Architecture

Microservices

Monolithic Architecture

Every entire application unit should feature the smallest size and serve one business goal

One business code serving all business goals

Setting up the service is easy.

Setting up the service is time-consuming.

Isolating a fault is simple. The system will continue running if one service breaks down.

Isolating a fault is difficult. The system will not run if one feature breaks down. You must rebuild, re-test, and redeploy the software system to solve this issue.

Loosely coupled microservices means a modification in one service cannot interfere with another service.

The tightly coupled monolithic architecture means a change in one software module will interfere with another software module.

Businesses can allocate more resources to software modules that generate higher ROI.

No individual resource allocation because of the tightly coupled services.

You can allocate more hardware resources to a frequently used service.

No application scaling because it is wasteful and challenging.

Microservices remain constant every time, and you can easily access them whenever you want.

Development devices are overburdened because the process always starts from scratch.

Federated data makes it simple for each microservice to implement a data model that matches its needs.

Centralized data.

Focused, small-sized teams promote parallel and speedy development.

Monolithic architecture needs powerful team management and a large team.

Changing the data pattern of a single microservice cannot interfere with other microservices.

Changing the data pattern of a single software module interferes with the entire database.

Uses well-defined application programming interfaces to pass a message to other microservices.

Not applicable.

The microservice principle focuses primarily on products and not projects.

Monolithic architecture focuses primarily on the whole project.

The code bases do not rely on each other. You can apply various technologies for various microservices.

The functions or programs rely on each other.

Microservices vs. SOA

Both Service Oriented Architecture and microservices fall under the category of service-based architectures. These two make it easy for developers to create small and de-coupled services that work independently in their unique environments.

Technically, microservices originated from Service Oriented Architecture because microservices implement SOA principles. However, there are a few subtle differences associated with these two architectures.

These differences relate to the service deployment and size of the software modules. The first difference involves the architectural design principle. The Service-Oriented Architecture works as per the 'share-much-possible' design principle while microservices work as per the ''share-little-possible'' design principle.

Microservices features fine-grained components and lightweight protocols, while Service-Oriented Architecture features more coarse-grained and larger modular services.

Furthermore, in Service-Oriented Architecture, communication occurs via an Enterprise Service Bus, while in microservices, communication takes place through an application programming interface.

In Service-Oriented Architecture, each component that aims to achieve a particular business goal utilizes a communication protocol like SOAP and ActiveMQ to share information with the Enterprise Service Bus.

Besides this, microservices feature quick and hassle-free scaling options and deployment, while Service-Oriented Architecture features less flexible scaling options and deployment.

Microservices vs. API

From the difference between application programming interfaces and microservices, you can easily tell if an application programming interface is truly a microservice.

In general, an application programming interface entails programming instructions that make it easy for computer devices to share functionalities and talk to each other. An application programming interface facilitates easy access to an application's information, making it easy for developers to collect the application's features and create powerful integrations.

Each element has got its unique application programming interfaces. For example, with a payment application programming interface, you can create an app that can send and receive payments. With a weather application programming interface, you can create an app that predicts the weather. Moreover, with a retail application programming interface, you can create an app that includes shopping capabilities.

Application programming interfaces play a pivotal role in ensuring microservices communicate with one another and respond to the client's request. Each microservice uses a unique application programming interface to interact with microservices located within the app.

Microservices stand for the architectural pattern that facilitates application creation as small-sized, autonomous services. On the other side, application programming interfaces enhance communication between the software isolated pieces featured in a microservice application.

You can treat an application programming interface as a microservice architecture element that makes it simple for various parts to communicate.

The current application programming interface evolutions have shifted microservices definitions to focus on REST Application Programming Interfaces.

Currently, REST Application Programming Interfaces have a larger market than the SOAP Application Programming Interfaces. This is largely why RSET Application Programming Interfaces are an important function in creating loosely coupled microservices.

Another point of interest is that Application Programming Interfaces can work even in the absence of microservices. You should use Application Programming Interfaces if you want two software machines to communicate with each other - a case that does not need microservices.

Advantages of Microservices

Enhanced Scalability

Microservices are preferred because of their scaling benefits. Since each microservice performs its functions independently, you can track and scale microservices separately without disrupting the entire application.

When service demand rises, you can seamlessly right-size the infrastructural requirements and improve the microservice to accommodate the spike.

The ability to isolate features and scale them independently explains why microservices are an excellent option for developing the latest, complex systems.

Improved Team Productivity

With microservices, you promote small teams that focus on achieving business objectives. Each unit enhances faster development cycles, increases autonomy, and increased flexibility by developing a particular feature.

Large teams record low productivity rates because of management challenges, poor motivation, and communication breakdowns.

Studies on the impacts of team size on software development projects show that small teams record higher quality scores than larger groups.

Microservices simplifies the process of onboarding new developers into various teams quickly. How is this possible? It is simpler to interpret the code of small and distributed services than those featured by an entire monolithic application.

Furthermore, with a microservices architecture, teams benefit from the freedom of choosing top-notch technologies and equipment they need to solve particular issues. This feature prevents developers from getting restricted to a single-fit-all technique.

Hence, the microservice architecture enables teams to mix different technologies, use modern technologies, or combine approaches that match their service. Also, with microservice architecture, teams can use functional software modules for several purposes.

For example, the team can reuse a service meant for a specific purpose to create another element without writing the element's code from scratch. With this feature, developers can save the businesses' resources and get more time to focus on their primary tasks.

Agility

You can effortlessly control various transitions during the microservice deployment process because the microservice architecture concentrates on modularity. This is a situation where each service performs its function independently.

Moreover, you can improve the microservice, update it, or resolve a bug without redeploying the whole system. A bug identified in one part of the system can interfere with the complete release process in a significant percentage of monolithic architectures.

Furthermore, it is hassle-free to separate faults in a microservice architecture. A microservice architecture will continue performing its function if one service breaks down. You cannot experience this feature with monolithic systems.

Resilient to Changes

Microservice architecture is difficult if you have to adapt to changes. On the other hand, loosely coupled microservices mean a change in one service cannot interfere with another service.

Developers can modify existing features or add new ones by altering a single software module's code instead of changing the entire app.

Reusable Functionality Modules

Microservice architecture makes it easy for developers to reuse the functional modules and utilize them on other applications. By putting into maximum use the already-prepared microservices, developers will save company resources and concentrate on other pivotal projects.

Transparent Model

Here, new employees can understand and improve the code due to app distribution in several microservices. It is hassle-free to handle one microservice compared to dealing with a whole integrated system.

There are various benefits of microservices for Agile and DevOps teams as they can update code effortlessly and utilize different stacks for various components. They can scale these components independently to reduce the cost and waste associated with scaling entire apps. This step is possible as a single feature may be overwhelmed with too much load.

Let's further explore the advantages of microservices for business.

Highly Accessible

With microservices, a large app is broken down into smaller pieces. This feature provides a greater understanding of those pieces that developers can then update and enhance. It becomes possible to accelerate development cycles, especially when IT brings agile development methodologies into the equation.

Efficient

Microservices provide teams with a boost through distributed development. Developing various microservices at the same time means that more developers can concentrate on the same app, reducing the time a business invests in growth.

Optimized For CI/CD

Microservices architecture breaks an app down to its key functions. You can build and deploy each part independently, meaning individual services can function without affecting the others. This feature enables developers to implement DevOps principles and make CI/CD more achievable. Also, microservice architecture goes beyond being more than simply the loose coupling of an app's core functions. It restructures dev teams and inter-service communication to prepare IT for future scalability, disaster recovery, and new feature integration.

Versatile

Microservices architecture supports Agile best practices and updates as development cycles are shortened, allowing you to accelerate time to market. Moreover, when you expand your business and increase demand specific functions, you can deploy microservices across multiple infrastructures or servers.

Easy Deployment

The small size and independently deployable microservices' nature represent the ideal solution in environments where small changes are time-consuming. Also, they bring together cross-functional teams around a business idea or product. Businesses can create small groups around a service or collection of functions and work together in an Agile way. The small size of services and communication patterns makes it easier for employees to understand the code base and contribute proactively to that codebase.

The list does not end here. Having small teams work in parallel enables your company to reiterate faster than large groups. You can also allow lifecycle automation by fitting components into continuous delivery pipelines or complicated deployment scenarios that monoliths cannot accomplish. Moreover, IT divides microservices architectures along business domain boundaries to increase understanding across an enterprise.

Risks and Potential Downsides

Complexity

Unlike monolithic architecture, microservice architecture features a larger percentage of moving parts.

Yes, you can easily manage each microservice, but you're likely to find a hard time controlling the entire microservice architecture.

You can find it challenging to develop and test the microservices application structure. The technique needed to create one microservice that works under other microservices' help can seem complicated when applied to create a typical monolithic application.

Besides this, a significant percentage of the existing development equipment design cannot work excellently with microservices featuring several interconnections.

Therefore, you're likely to find it complicated to complete refactoring across the service boundaries. Also, you'll find a challenge in testing the interdependencies, especially when the microservices grow rapidly.

Huge Operational Overheads

Be ready to spend more if you plan to implement microservices. The microservices deployment on various services is the reason behind these huge costs. The microservices application can demand several central processing units and runtime environments because of this deployment.

Furthermore, microservices complete several remote calls on a significant percentage of occasions because each microservice should communicate with other microservices from time to time. All these issues contribute to the huge operational costs.

Moreover, the microservices' increased security needs also widen the operational costs more. The microservices architecture decentralized approach opens more 'loopholes' for attacks. Therefore, protecting a microservice architecture from malicious attacks should be a priority.

Complicated Governance

A microservices architecture uses a beneficial decentralized methodology, but chances are you will find it hard to govern it.

As microservices increase, third-party resource integration and technology entrenchment also increase in the same manner. Here, it is not easy to gain visibility and manage the entire microservice application.

Hence, setting up a logging system and centralized monitoring system is the step to take if you want to develop a successful microservices architecture. With these features, you will easily assemble all things in one area and note all problem sources.

Also, through these features, you can manage different teams with ease. This system allows you to note problems early enough and prevent all the difficulties associated with governing microservices.

Performance

The microservice architecture complexity also affects its performance. The microservices efficiency is likely to be slower than in monolithic apps because it features inter-process communication and several Java Virtual Machines.

Security

The microservices architecture needs higher securing measures because they exchange data over the network. Therefore, microservices need continuous upgrades and maintenance.

How to Implement Microservices

You're likely to get intimated at first if you plan to switch from the traditional software architecture to microservices architecture. However, the process will not be challenging because other companies have tried and tested microservices.

You only need to follow some best practices and implement microservices successfully. Before you start,  note that you can develop each microservice architecture using a unique programming language and technology.

As a result, the technology involved in developing a single software module is of less value than the overarching technologies needed for communication purposes and integration.

Get on one page

When implementing a microservices architecture, all developing team members must be thoroughly engaged. Consider putting all your attention on this because transitioning from traditional architecture to modern microservices architecture involves changing organization mentality and culture.

Besides each team member remaining truly independent, a successful microservice architecture execution needs shared application programming interface documentation, logging formats, and communication standards.

Define Target Architecture

The primary aim of microservices architecture is to ensure a company has a less complex software landscape. However, the microservice architecture can create chaos or more complexity when designed wrongly and under incorrect management.

So, you should define the target architecture's look before starting the microservice implementation process. Besides removing all the contradicting dependencies, also ensure the information remains consistent across each microservice. Moreover, consider upgrading your network to prevent microservices traffic.

Keep Monitoring

When you break up a large app into smaller apps, each application produces several logs that you should analyze.

As a result, it is pivotal to create a clear plan of monitoring each microservices from time to time. You can observe them via service error notifications or response time notifications.

You can facilitate monitoring and create a detailed overview using cloud intelligence tools, monitoring tools, logs, and dashboards.

Examples of Microservices in the World

Amazon

Amazon is the world's largest e-commerce company that transformed its retail site into a huge monolithic architecture in 2001. This company broke down its apps into small, service-specific, and independently-deployable components to scale the services it offers, and it deploys the changes within the shortest possible time.

Hence, Amazon started using the microservices concept even before this term's invention. Consequently, the microservices architecture concept made to clean Amazon's systems emerged to become microservices.

Moreover, with this concept, Amazon created a vast range of solutions that promote microservices adoption, like the widely known Amazon Web Services. Shifting to microservices contributed a lot to Amazon's current status.

Netflix

Netflix falls under the category of the most used video streaming services. This service contributes around 15 percent of the overall worldwide internet traffic.

Netflix revolved in 2010 when it shifted from a monolithic architecture to microservices, making it amongst the top-rated companies using microservices.

The microservices term had not come to the market when Netflix began creating apps that manage their video streaming service. Today, an advanced and powerful microservice architecture runs Netflix's streaming service. This architecture entails more than five hundred microservices that make more than two billion application programming interface requests every day.

Uber

Uber enjoys several benefits because of the implemented microservice architectural style. After implementing this style, uber managed to assign transparent ownership of particular services to each development team  - a feature that enhanced new development manageability, quality, and speed.

The microservice architectural style promoted fast scaling by making it easy for teams to focus on the scaling services. Also, this style made it possible for Uber to update each service without interfering with other microservices. Moreover, uber managed to attain reliable tolerance because of this style.

Keep Learning

Microservices architecture can supercharge your applications' capabilities through distributed development. This architecture is the perfect option for creating multi-functional and complex apps capable of meeting the current user-centered and agile application demands.

However, consider evaluating your requirements carefully and the abilities to meet the microservices architecture needs before choosing this style.

At Scout APM, we provide a top-notch API management platform where you can gain forensic APIs visibility and boost their discoverability. With Scout, you can monitor your APIs performance, enhance productivity by establishing team-wide collaboration, and more.