Part 1- Microservices: An Introduction
Microservices, though not a new concept, has recently attracted a lot of attention. Uber, Netflix, Google, and Amazon, among others, have adopted this as an architecture of choice.
Let us delve deeper into the architectural composition of Microservices to understand what exactly it is, and understand the benefits and challenges associated with it.
Microservices, as the name corroborates, is an architectural design that divides a complex app into more logical, isolated, decoupled and independent smaller services. These services are autonomous of each other, and hence, independently deployable and testable, and easy to replace. They communicate with each other using simple APIs. The code for each service can be written in a different programming language, and different data storage technologies can be used, calling for minimal centralized management.
This architecture assists in creating more resilient, scalable and flexible systems that enable rapid development. The necessity to understand the entire code is purged due to relatively short, manageable and easy to read code for each service.
The flip side, however, is that as the numbers of these mini services increase, it becomes difficult to integrate them. Also, they must be scrupulously tested before integration, or later, the implications of a single mistake could be huge in terms of both cost and time.
But how is this architecture different from the Service Oriented Architecture (SOA)?
Microservices Vs SOA
Let’s observe some of the major differences in the architectural styles through the following illustrations:
1. Microservices are significantly small services that can operate independently and can be autonomously developed, deployed or replaced, unlike SOA. A SOA can be either a monolith or it can comprise of multiple Microservices.
2. Microservices architecture revolves around reactive programming style while SOA centers on imperative programming.
3. Microservices use quick messaging mechanisms, while SOA normally has dependent ESBs (Enterprise service buses).
4. In Microservices, each service can have an independent data storage, while in SOA, services share the data storage.
Now that we understand how the architectures differ, let us focus on the benefits that Microservice Architecture offers.
Benefits of Implementing Microservice Architecture
1. Organized around Business Capabilities: Rather than technical capabilities, Microservices are organized around business capabilities.
2. Autonomous Components: The architecture enables loosely coupled services that can be independently developed, scaled and replaced.
3. Technology Stack Flexibility: For a specific service, software teams using Microservices architecture can introduce a new stack.
5. Focused Functionality: Typically, a Microservice is organized around a single focused capability, and is hence better manageable. The code is small and is thus easy to maintain.
6. Application Scalability: As one application is composed of multiple Microservices that share no external dependencies, scaling a particular Microservice instance is easy.
7. Allowance for Different Languages: Different services can be written in different languages for later integration into the main application, thus embracing flexibility and technology diversity.
8. Decentralized Data Management: Decentralization allows for teams to work independently as each service manages its own database.
9. Automated Deployment: With independent implementation, Microservices can easily be moved from one deployment environment to another.
Challenges Posed by Microservice Architecture
1. Compatibility Issues: Built by different teams using different technologies, Microservices often face compatibility and integration issues. This results in an unstable environment.
2. Increased IT Costs: Implementing Microservices with Big Data Project can be quite costly. Hiring skilled experts and training staff to learn new codes for integration and getting access to additional servers and database licenses can prove expensive.
3. Application Security Issues: With different OS, frameworks, and languages, it is not easy to keep the system secure from hackers. Also, there are not many Open Source tools, frameworks, and models to support Microservice dependent software.
4. Complex Fault Tolerance: In this architecture, service failure can go multifold creating a cascading effect and is difficult to handle than in a monolithic system, especially with a high number of services and processes.
5. Resource Rivalry: With the development of a few dozen Microservices in the process, it becomes difficult to ensure access to scarce, complicated and expensive hardware and engineering resources to all the teams.
6. Monitoring Troubles: System state keep changing in Microservice architecture, and it becomes essential to remain aware of the system at all times. A lack of this may result in system failure.
7. Stability Issues: Frequent changes and faster deployments with different technologies and languages coming together, it is quite difficult to ensure stability.
8. Testing Complexities: Managing the testing complexity of multiple independently deployable components is a daunting task for testers.
Adoption of Microservices Architecture is currently a topic of major interest in the app development community. The architecture offers faster delivery, greater operational resilience and scalability, decentralized data management, and technology diversity. However, like other architectures, it also has its own set of challenges. Higher costs, resource scarcity, monitoring troubles, testing complexities, stability and compatibility issues, all pose failure risks.
Despite these risks, the adoption of Microservices can be highly effective if the right tools and solutions are used to address operational and security issues. In our next blog – Part II- Microservices: Software Testing Challenges and Strategies, we will be focusing on the specific software QA testing challenges that Microservices pose, and the testing strategies that can overcome these challenges leading to a secure and reliable system.