What Are Microservices?
A microservice is a modular software component that does one defined job. Microservices, which have become the default architecture for software development, can run as a process on an application server, virtual machines (VMs), or, more commonly, containers.
Each microservice can be explained as a mini-application – small, autonomous services that work together. Each is an independently deployable service with its own business logic and adapters for carrying out functions, such as database access and messaging. The resulting application will have small, loosely coupled components that communicate with each other using lightweight communication protocols. This minimizes dependencies between components, allowing for easier updates and scaling.
Microservices typically communicate with each other using application programming interfaces (APIs). They define the kinds of requests that can be made, how to make them, the data formats that should be used, and so on.
Examples of communication protocols include:
- Advanced Message Queuing Protocol (AMQP)
- Google remote procedure call (gRPC)
- Representational state transfer (REST)
- WebSocket
Microservices are used to develop distributed software applications that run in the cloud, facilitating faster development, testing, and deployment. Because each transaction involves the transmission of messages across a network, it’s important to consider network security, reliability, and latency when considering moving to a microservice architecture.
Key Takeaways
- A microservice is a modular software component that does one defined job.
- Each microservice is a mini-application that has its own business logic to carry out functions.
- They minimize the risk of unforeseen interdependencies impacting other services.
- Microservices communicate through APIs, often managed by an API gateway.
- In the cloud, they enhance scalability and improve resource efficiency.
How Microservices Work
In a microservice architecture, a collection of independently functioning services is developed and deployed separately. Each service has one defined job, allowing updates to take place for a single service without disrupting the functionality of others. This minimizes the risk of interdependencies impacting other services.
For example, in an e-commerce application, microservices separate functions such as authentication, payment processing, product catalog, and shopping cart. While separate, the services communicate through APIs, often managed by an API gateway, to create a seamless online shopping experience for the customer. For service providers, when a service requires an update, only that service is impacted, leaving the remaining online and functional.
Microservices Architecture
The microservices architecture, often used in DevOps, is built on several core principles rather than official standards.
Common principles and best practices include:
Microservices Tools
Microservices tools are software used by developers to help build, deploy, and maintain apps using a microservices architecture. Typically they provide solutions to manage services like communication, deployment automation, scaling resources, and monitoring performance. Types of microservices tools include: AWS Lambda, Docker, Kubernetes, Apache JMeter, and others.
What Is a Microservice in the Cloud?
Microservices in the cloud refer to the collection of independently functioning services running on cloud infrastructure to build a complete application. In the cloud, microservices typically run as a process using technologies like containerization, VMs, or serverless computing. Cloud infrastructure enhances scalability by allowing more instances of a service to be added without needing to upgrade hardware. Microservices in the cloud are generally considered cost-efficient as organizations pay only for the resources used.
Microservices Pros & Cons
Pros
- Each of the components can be scaled independently
- Enables development teams to produce updates more quickly
- Microservices allow iPhone or Android apps to access backend services
- Multiple teams can work independently on the same component
- The independent functional nature promotes the reusability of code across applications
- Streamlines communication through lightweight protocols
Cons
- May impact network security, reliability, and latency
- Managing distributed systems can be complex
- Microservices architecture requires API management and a Zero Trust security strategy
- Multiple microservices need to be monitored as a single application
- Version management can be challenging (i.e., when the same component has to call the latest version for one client and a previous version for another)
The Bottom Line
The microservice definition refers to a software architecture where applications are divided into small, independently deployable services, each performing a single defined job. These services communicate using lightweight protocols like REST or gRPC and are often managed through an API gateway. Microservices enhance scalability, enable faster updates, and promote resource efficiency, especially in cloud environments.
While they reduce dependencies and improve flexibility, they also require API management, monitoring, and a strong focus on security to address challenges like network latency and reliability.