A detailed exploration of service-oriented architecture vs. microservices to help you navigate the best architectural option for your organization.
Service-Oriented Architecture vs. Microservices: Choosing the Right Option
If you work in any area of IT or are involved in decision making about purchasing IT services, you could be forgiven for sometimes being confused by the raft of new terms that have evolved in recent years.
That can be especially true if you’re looking at modernizing monolithic applications and legacy systems that you want to operate efficiently in a modern digital environment.
When it comes to modernizing those legacy systems, there are usually two architectural options open to you; service-oriented architecture (SOA) or the microservices architectural style.
What are the key differences between these two options and, more importantly, how do you decide which is best suited to your organization?
Differences between microservices and SOA
The obvious starting point when looking to compare SOA and microservices is to fully understand what each term means; building a solid basis from which you can make your decision.
What is service-oriented architecture?
As the name would suggest, SOA focuses on the services you use and provide, and is an approach for building a software environment—and software—that encompasses all aspects of enterprise level development.
Therefore, the immediate service-oriented architecture advantages are that your developers can achieve reusability of components from your enterprise’s existing applications.
SOA allows for the development of a series of modular web services across your organization that can easily communicate with each other and thus support all your applications.
One standout feature of SOA is that it allows for an easy communication protocol between any different platforms you use (such as Microsoft Azure or Amazon Web Services [AWS]), as well as different programming languages such as Java (through using JMS or Java messaging service).
SOA’s structure is based on the idea of decreasing the coupling between the applications you use (also known as decoupling or loose coupling). This allows two applications to communicate with each other even if they’re completely different.
In turn, this leads to improved business functionality and makes the development of new software and software architecture easier.
If you choose to go down the SOA route, you will find there are four different SOA services you can utilize:
- Functional: This is the general SOA service relating to all your business-oriented apps.
- Enterprise: This service is used when you want to implement specific functional services.
- Application: used by your DevOps team for developing and deploying new apps.
- Infrastructure: This aspect of SOA services is used for non-functional features, most often used for authentication and other security aspects.
The simplest way to think of microservices is as an extension of new or existing SOA.
Using APIs (Application Programming Interfaces), the different components of your microservices architecture pattern communicate with one another. Every microservice you use is focused on a single business domain/function and organizes a dedicated network for that function.
With microservices, you can combine components to create more complex apps and also higher-level services. Modernizing your legacy system with microservices architecture and middleware lets you create applications’ systems as single-purpose units that are mostly unique from each other.
The structure of microservices is fairly simple and straightforward. Any applications you use are broken down into specific functions and objectives. If you look at the image above, you can see how an e-commerce app has been built using microservices and that there are three essential features to that app:
- Inventory and inventory management
- Logistics and shipping
If you’re using microservices, the architecture dictates that each of those features has its own independent components. Those components have their own independent data storage.
This is a basic principle of microservices architecture; every resource must be a standalone feature that can communicate with others when needed via a messaging system.
Microservices architecture can make your developers’ jobs far easier as it lets them not only update the codebases with little effort, but also allows for scalability without using different code components.
Microservices mean your teams can choose and create different tech stacks and bounded context for component sharing and then connect them all using APIs.
You will also find that with microservices, fault tolerance and load balancing levels are high because every component manages itself independently.
When using—or creating—applications based on microservices, they’ll most likely be hosted on the cloud, offering better efficiency and cost-effectiveness.
Benefits of service-oriented architecture and microservices
The second stage in making your decision is to examine the benefits of using microservices vs. SOA, both generally and in direct relation to your business needs and model.
A major issue within larger organizations is that there can be communication and collaboration problems due to silos, particularly between business services and your IT teams.
With SOA, all independent services are defined in business terms, making collaboration easier and allowing different areas of your business to work better with your developers to ensure better results from your business processes and apps.
Because every SOA service includes all the code and data to complete individual functions, service interfaces provide loose coupling (also known as decoupling).
That reduces interdependency between applications as the interfaces need little or no knowledge of how the actual service is implemented.
Aligned project development
Before SOA existed, connecting your apps to relevant data—and its granularity and functionality in other systems—was a complex process involving point-to-point integration. This process had to be replicated for every new development project.
SOA ESB (Enterprise Service Bus) means that developers can reuse existing capabilities and align the development of different projects.
Easy to maintain
Your IT managers know that software lifecycles can mean costly maintenance (or replacement) as well as potential downtime of systems.
With SOA, it can be easy to maintain, update, or modify one service without affecting the functionality of other services. This all makes it easier for your IT staff to work on SOA systems due to its modularity.
Simplified process adoption
If you choose microservices to modernize your legacy systems, then it’s easier to adopt new tech and processes when updating your tech stack. This means you can expand the apps that you offer with little to no difficulty. Combining microservices with APIs can lead to easily scalable tech stacks.
Enhances error tolerance
With SOA, the use of an ESB means that a single error could cascade into other aspects of the application.
With a microservices architecture, you get a higher degree of error tolerance. If an issue does arise with one service, then only that microservice would be affected, and the others would function as expected. There is also the issue of value for money, and many businesses seek to reduce reliance on Tibco ESB.
Because microservices architecture offers extensive modularity, your DevOps or IT teams can deploy new and independent apps without affecting any other area of your architecture.
This means your developers can add new modules without making any changes to your system. It further means that you have the freedom to add new features and dependencies as and when you need them.
Flexible and can stand-alone
Microservices are cloud-based and native, and thus, mean your developers can build and deploy standalone applications designed to perform a specific function.
This offers you and your DevOps teams more flexibility than other options as they can develop more agile, scalable, and resistant applications that offer different services.
Speed in your workflow can often be crucial when it comes to application or software development. Microservices allow your application development teams and IT teams to work closely together, and decentralization means that innovation happens faster, your teams have more control over tech stacks, and can manage development and release faster, too.
Enables independent scaling
If you’re still working with a monolithic system, then every time you scale a single component of an application, you usually need to scale the entire application, too. With microservices, you can identify which services or components need to be scaled and then scale each independently of the others.
Microservices and service-oriented architecture examples
Of course, it’s all very well comparing the benefits of service-oriented architecture vs. microservices and considering how they might affect your organization. But how do these two options actually work in the real world?
Looking at real-life examples of how businesses have adapted either type of architecture can help you see how one or the other might work for you.
Like many other financial institutions, Panama’s Credicorp faced real challenges in modernizing its monolithic architecture and embracing the era of digital banking.
Using OpenLegacy’s platform for API/microservices integration meant that the bank could quickly transform its service and use customer data to give it a true 360° view of customer wants and needs and achieve automation of many services.
Another financial institution—but focusing mainly on credit cards—Isracard faced the challenge of integrating a new IVR (Interactive Voice Response) system with its legacy mainframe containing customer data.
OpenLegacy offered a microservices integration solution that was integrated faster and cheaper than other options.
Utility company Delaware Electric faced real issues due to a five-year freeze on electricity prices imposed by the state. They needed to integrate systems that didn’t communicate with each other, so that they could remain solvent. Using SOA architecture helped them achieve that goal.
Independence Blue Cross
Healthcare service provider Independence Blue Cross needed a system that would allow different teams (such as customer service agents or physician’s offices) to access a “single source of truth” in relation to patient information.
Implementing SOA ensured that all constituents involved could access accurate data in real-time.
Service-oriented architecture (SOA) vs. microservices: Which is better?
Deciding which option is better for you will depend on a number of factors, such as particular use cases, the current level of IT infrastructure, resources, and short and long-term business needs. What that means, in reality, is that there is no definitive answer as to which of the two is better.
However, that said, in many cases, businesses will prefer to opt for microservices as they will bring multiple advantages.
While SOA offers high levels of integration through ESBs, deployment tends to be far slower and more complex than microservices architecture, so this is something to think about.
Microservices architecture is usually easier and faster to build and deploy as individual services are smaller and thus can be deployed more quickly. SOA may be more suited to organizations needing a solid communication platform and messaging protocols, but microservices offer the speed, flexibility, agility, and lower costs many businesses desire.
FAQs about SOA vs. microservices
When should I use microservices?
Microservices are an ideal solution in the following scenarios:
- When you have lots of simple projects that are easily broken down.
- If your business wants agile development and a continuous delivery process.
- When you have complex application services that can be broken down or have already been broken down.
- If your DevOps teams and your applications benefit from multiple programming languages, frameworks, and tech in the same environment.
- When your organization wants to optimize its use of cloud computing, especially through containerization.
When should I use service-oriented architecture?
SOA can be particularly useful if you want to achieve any of the following:
- Communication between lots of independent apps. This can often be done with SOAP (Simple Object Access Protocol).
- Supporting a single application environment that uses multiple data sources.
- Building and deploying a service that can be used in different areas of your enterprise.
- Achieving serverless functionality.
- Sharing functionality and/or data with external clients or partners.
What is the main purpose of service-oriented architecture?
The main purpose of SOA is to ensure that software components can be reused and that they’re interoperable by using service interfaces.
SOA services use common user interface templates, so it’s easier to incorporate them into any new apps. It helps solve the issues posed by a fragmented IT architecture as well as the difficulties in working with IT infrastructure services and app silos.
What are the characteristics of service-oriented architecture?
The main characteristics of SOA include:
- Supports high levels of interoperability.
- Allows for vendor diversity and heterogeneous solutions.
- Helps promote discovery.
- Increases your service consumer quality.
- Supports loose coupling (or decoupling) anywhere in your project.
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