Monolith to Microservices: Architectural Change

introduction

In the world of software development, with the growth of business and the development of technology, the traditional single application structure has gradually exposed its limitations.

At the same time, as an innovative software design pattern, microservice architecture has won the favor of more and more developers due to its excellent flexibility, scalability and autonomy.

The purpose of this article is to analyze the characteristics, advantages and disadvantages of a single application structure, and to explore the process and importance of transitioning from a single application structure to a microservice architecture by comparing it with a microservice architecture.

Monolithic architecture overview

单体架构是一种将整个软件系统构建为一个单独单元的传统方法。这个单元通常是作为一个单一的可执行文件或者紧密集成的软件包存在。单体架构具有以下几个显著特点：

• Simple and intuitive : The development process is relatively simple, easy to understand and maintain, and especially suitable for small projects to get started quickly.
• Easy deployment : You only need to deploy the entire application to one server, without the need for a complicated deployment process.
• High development efficiency : The project is small in the early stages, so developers can quickly implement features and iterate quickly.
• Unified technology selection : Using the same technology stack avoids the complexity caused by technology diversity.

However, the monolithic architecture also has obvious drawbacks:

• Poor scalability : As the business grows, the system becomes large and complex and difficult to expand.
• Low reliability : Once a problem occurs in a module, the entire system may crash.
• Performance bottleneck : When processing a large number of concurrent requests, performance is limited, and response time and throughput are difficult to guarantee.

Advantages of Microservice Architecture

To overcome the shortcomings of monolithic architecture, microservice architecture came into being. Microservice architecture is achieved by decomposing the application into a series of small, loosely coupled services. These services are organized around business capabilities and can be independently deployed, expanded, and maintained. Compared with monolithic architecture, microservice architecture has the following advantages:

• Better scalability : Each service can be scaled independently as needed.
• Higher reliability : Even if one service fails, it will not affect other services.
• Diversified technology stack : allows you to choose the most suitable technology stack based on the specific needs of the service.

1. Simple and intuitive: The development process is relatively simple, easy to understand and maintain. For small projects, developers can quickly get started and complete system development in a short time.

2. Easy deployment: You only need to deploy the entire application on one server, without the need for complex deployment processes and coordination of multiple servers.

3. High development efficiency: In the early stages of a project, due to the small scale of the system, developers can quickly implement functions and iterate quickly. All codes are in one project, which is convenient for developers to debug and test.

4. Unified technology selection: The entire system uses a set of technology stacks to avoid the complexity caused by the diversity of technologies. Developers can focus on the in-depth study and application of one technology to improve development efficiency.

1. Small projects

Monolithic architecture is a good choice for projects with relatively simple functions, small number of users and small amount of data, such as internal management systems of small enterprises, personal blog websites, etc. These projects usually do not require complex architectures to support high concurrency and large-scale data processing. Monolithic architecture can be developed and deployed quickly to meet the basic needs of the project.

2. Projects in the early stages of development

In the initial stage of a project, the requirements are often unclear and the business logic is relatively simple. At this time, the use of a monolithic architecture allows the development team to quickly build a usable system prototype for verification and iteration. As the project develops, if it is found that the monolithic architecture cannot meet the requirements, you can consider upgrading and transforming the architecture.

3. Projects with low performance requirements

If the project does not have particularly stringent performance requirements, the monolithic architecture can be competent, such as some low-frequency tool software, small data analysis systems, etc. These systems do not need to handle a large number of concurrent requests, and the performance bottleneck of the monolithic architecture may not be obvious in these scenarios.

Nginx and Ribbon are two tools used to implement load balancing in distributed systems, but they each have different positioning, applicable scenarios, and configuration methods.

1. Functional Positioning

Nginx

• Nginx is a high-performance web server, reverse proxy server and load balancer, mainly used to distribute requests and perform load balancing at the network level.
• It is usually deployed at the front end of a server cluster as a unified entry point to receive requests from clients and forward these requests to different backend servers according to predefined policies.
• Nginx supports multiple load balancing algorithms, such as round-robin, weighted round-robin, IP hash, etc.

Ribbon

• Ribbon is a client-side load balancing tool that selects the appropriate service instance for access based on a pre-set load balancing strategy when a client makes a request.
• It usually works with microservice frameworks such as Spring Cloud. In the microservice architecture, each microservice client uses Ribbon to achieve load balancing for the service provider.
• Ribbon provides several load balancing algorithms such as polling and random.

2. Usage scenarios

Nginx

• It is suitable for large-scale distributed systems that handle high-concurrency requests, and performs particularly well when faced with a large number of external requests.
• Nginx can provide load balancing for various types of requests (such as HTTP, HTTPS, TCP, UDP) and has a wide range of applications.
• It also supports static resource serving and caching, which helps improve system performance.

Ribbon

• In a microservice architecture, Ribbon is an ideal choice when load balancing is required for multiple service providers.
• Implementing load balancing on the client side reduces reliance on external middleware and simplifies the deployment and maintenance process.
• It allows customizing the load balancing configuration based on the needs of specific microservices.

3. Configuration method

Nginx

• Nginx's load balancing strategy and backend server list are set through its configuration file. The configuration file uses a special syntax and requires certain Nginx configuration knowledge.
• Although some configurations can be modified dynamically at runtime, the process is more complicated.

Ribbon

• The configuration of Ribbon is generally completed in the microservice client code, and the load balancing strategy can be set through code comments, configuration files or programming.
• This approach is more flexible and can be customized according to different microservices.

4. Performance characteristics

Nginx

• As a professional server software, Nginx has the ability to handle a large number of requests and is particularly suitable for high-concurrency scenarios.
• The efficient processing and optimization capabilities of network protocols improve the system's response speed.

Ribbon

• Although it may not be as powerful as Nginx in performance, in a microservice architecture, Ribbon can usually meet the needs considering the relatively small request volume.
• Its main advantage is that it is highly integrated with the microservice framework, making it easy to develop and use.

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Eureka - Service registration and discovery framework

Eureka is a service registration and discovery framework designed to help manage service instance registration and discovery in a microservice architecture.

Core Features

• Service registration : When each microservice starts, it reports its own information to the Eureka registration center, such as service name, IP address, port, etc.
• Service discovery : Microservices can query other service instance information through Eureka to implement direct calls.

How it works

• Client-server interaction : The microservice client maintains its registration status on Eureka through the heartbeat mechanism; at the same time, the client also regularly pulls updates to the service registry.
• Self-protection mechanism : In the event of a network failure, Eureka enters self-protection mode to avoid erroneous removal of service instances due to temporary communication problems.

Advantages

• High availability : Eureka supports cluster deployment, which improves the robustness and availability of the system.
• Easy to integrate : Tightly integrated with microservice frameworks such as Spring Cloud to accelerate the construction of service registration and discovery systems.
• Flexible configuration : parameters such as heartbeat interval and self-protection threshold can be adjusted according to actual needs.

Application Scenario

• Microservice architecture : Eureka is suitable for managing dynamic changes of service instances in large-scale microservice systems.
• Cloud-native applications : Applicable to applications deployed in the cloud, supporting automatic scaling and fault migration.

in conclusion

Although monolithic architecture still shows its unique advantages in certain situations, with the increase in business complexity and the driving force of technological progress, the transition to microservice architecture has gradually become mainstream.

Microservice architecture can not only solve many challenges faced by traditional monolithic architecture, but also provide enterprises with a more flexible and efficient IT infrastructure.

However, the choice of any architectural pattern should be based on specific business requirements and technical environment, so a comprehensive assessment should be conducted in actual operation to make the most appropriate decision.