Microservices - Not Just About Scalability
Posted by bsstahl on 2023-01-30 and Filed Under: development
Scalability is an important feature of microservices and event-driven architectures, however it is only one of the many benefits these types of architectures provide. Event-driven designs create systems with high availability and fault tolerance, as well as improvements for the development teams such as flexibility in technology choices and the ability to subdivide tasks better. These features can help make systems more robust and reliable, and have a great impact on development team satisfaction. It is important to consider these types of architectures not just for systems that need to scale to a high degree, but for any system where reliability or complexity are a concern.
The reliability of microservices come from the fact that they break-down monolithic applications into smaller, independently deployable services. When implemented properly this approach allows for the isolation of failures, where the impact of a failure in one service can be limited to that service and its consumers, rather than cascading throughout the entire system. Additionally, microservice architectures enable much easier rollbacks, where if a new service version has a bug, it can be rolled back to a previous version without affecting other services. Event-driven approaches also decouple services by communicating through events rather than direct calls, making it easier to change or replace them without affecting other services. Perhaps most importantly, microservice architectures help reliability by avoiding dual-writes. Ensuring that our services make at most one state change per execution context allows us to avoid the very painful inconsistencies that can occur when data is written to multiple locations simultaneously and these updates are only partially successful.
When asynchronous eventing is used rather than request-response messages, these systems are further decoupled in time, improving fault-tolerance and allowing the systems to self-heal from failures in downstream dependencies. Microservices also enable fault-tolerance in our services by making it possible for some of our services to be idempotent or even fully stateless. Idempotent services can be called repeatedly without additional side-effects, making it easy to recover from failures that occur during our processes.
Finally, microservices improve the development and support process by enabling modularity and allowing each team to use the tools and technologies they prefer. Teams can work on smaller, independent parts of the system, reducing coordination overhead and enabling faster time-to-market for new features and improvements. Each service can be deployed and managed separately, making it easier to manage resource usage and address problems as they arise. These architectures provide greater flexibility and agility, allowing teams to focus on delivering value to the business without being bogged down by the constraints of a monolithic architecture.
While it is true that most systems won't ever need to scale to the point that they require a microservices architecture, many of these same systems do need the reliability and self-healing capabilities modern architectures provide. Additionally, everyone wants to work on a development team that is efficient, accomplishes their goals, and doesn't constantly force them to wake up in the middle of the night to handle support issues.
If you have avoided using event-driven microservices because scalability isn't one of the key features of your application, I encourage you to explore the many other benefits of these architectures.
Barry S. Stahl (he/him/his) - Barry is a .NET Software Engineer who has been creating business solutions for enterprise customers since the mid 1980s. Barry is also an Election Integrity Activist, baseball and hockey fan, husband of one genius and father of another, and a 40 year resident of Phoenix Arizona USA. When Barry is not traveling around the world to speak at Conferences, Code Camps and User Groups or to participate in GiveCamp events, he spends his days as a Solution Architect for Carvana in Tempe AZ and his nights thinking about the next AZGiveCamp event where software creators come together to build websites and apps for some great non-profit organizations.