The Difference Between Serverless And Microservices

Today, we’re diving into Serverless and Microservices, two popular architectures for building and deploying applications. If you're just starting your journey into cloud computing or looking to brush up on your knowledge, understanding these two architectures is crucial. We're going to go through and break down both paradigms. At the end you'll have a better understanding of their strengths and weaknesses as well as how they differ from one another.

What are Microservices in Software?

First, let’s talk about Microservices. Imagine you’re building a complex application. Instead of creating one massive, monolithic structure where every component is tightly coupled, you break it down into smaller, independently deployable services. Each service, or "microservice," handles a specific business function.

In a microservices architecture each microservice is built around a boundary in your system's domain. Think of them as a collection of small, focused applications working together to form a cohesive system.

In fact, a common migration technique for monolithic applications to microservices is to look at the natural domain boundaries that exist already in your application. When you find them, you then convert each separate area one by one into independent services. You use the interface of the previous service or services that comprised the monolithic version to define the data contract. 

Let us go through a common microservices example. For instance, let's say you had an e-commerce web application, built as a monolith. You might have admin routes responsible for adding new products.

You might also have routes for the user's shopping experience with saved products, their cart etc. In this example the only overlap they have is the products data model.

In this case you would say the responsibilities of these subsystems are mostly separate. Because they are separate you could create multiple microservices. One service for product admin like adding new products and one service for the user shopping experience.

Together they act as a distributed system where each service operates independently. This is what makes it a service oriented architecture or SOA.

Micro services work best when each service has its own data store. In this case, the products model should be managed by the product admin API. The user experience API can then retrieve product information by communicating with the product API, rather than sharing a database.

That is Microservices explained through a typical example that might happen as a company.

Key Features of Microservices:

• Independence: Each microservice can be developed, deployed, and scaled independently.
• Decentralized Data Management: Services manage their own databases, reducing dependencies and enhancing flexibility.
• Data Contracts: The microservices approach require strong data contracts between each other, often these interfaces are versioned and require maintaining backwards compatibility.
• Polyglots Persistence: You can use different technologies and languages best suited for each service.

What is Serverless?

Now we can discuss Serverless. When you go Serverless, you’re essentially saying goodbye to server management. Servers always exist, you just don't have to worry about them. With this architecture, you write your code, and the cloud provider handles the rest.

Functions are the primary unit of work in Serverless architecture. You write discrete functions triggered by events, and the cloud provider executes them on-demand, scaling automatically as needed.

Key Features of Serverless:

• No Server Management: You don’t worry about infrastructure. The cloud provider takes care of provisioning, scaling, and managing servers.
• Automatic Scaling: Functions scale up and down automatically based on demand.
• Pay-as-You-Go: You’re billed only for the compute time you consume, making it cost-effective for variable workloads.

For a more in-depth look at serverless architecture you can check out our deeper post on the topic.

Comparing Microservices and Serverless

1. Architecture and Design

• Microservices: Designed for building complex applications with multiple services that are loosely coupled. Each service can be independently developed and maintained.
• Serverless: Focuses on individual functions rather than full-fledged services. Ideal for event-driven applications and short-lived processes.

2. Scalability

• Microservices: Requires manual scaling strategies. You need to plan and implement how each service scales, which can be intricate but allows fine-grained control.
• Serverless: Automatically scales based on demand. No need to worry about provisioning resources as the cloud provider handles it.

3. Cost Efficiency

• Microservices: Can be more cost-effective for steady workloads, but you might incur costs for idle resources and over-provisioning.
• Serverless: Operates on a pay-as-you-go model, making it more cost-effective for workloads with unpredictable traffic patterns.

4. Development Speed

• Microservices: Increases development speed for large teams. Each team can work on different services simultaneously without stepping on each other’s toes.
• Serverless: Speeds up development by abstracting away infrastructure management, allowing developers to focus purely on writing code.

5. Security

• Microservices: Benefit from strong service to service encryption through service meshes and mTLS as well as standard software security practices.
• Serverless: Benefit from a range of security practices, such as least privilege. They have increased complexity because security is handled on a per function basis. We discuss serverless security in more depth in this blog post.

6. Complexity

• Microservices: Can introduce complexity in terms of service communication, data consistency, and deployment orchestration.
• Serverless: Simplifies the development process but can introduce challenges in managing function dependencies and cold start latency.

7. Fault Tolerance

• Microservices: Each service is fault isolated from one another, but otherwise common patterns for handling app crashes still apply.
• Serverless: Errors happen at the function level, and independent function runs are completely isolated from one another providing strong recovery guarantees.

8. Use Cases

• Microservices: Microservices in the cloud are great for large-scale, enterprise-level applications where different teams handle different business domains.
• Serverless: Perfect for small to medium-sized applications, real-time data processing, IoT backends, and apps with variable load.

Which One Should You Choose?

The choice between Microservices and Serverless depends entirely on the needs and resourcing of your organization as well as the business requirements:

• Choose Microservices if: You’re dealing with a large, complex application and that application benefits from high modularity, independent scaling, and flexibility in technology stacks. You also need to have the team(s) to support managing multiple independent services. For this reason enterprise microservices are more common.
• Choose Serverless if: You want to minimize operational overhead, have variable workloads, and need a rapid development cycle and deployment cycles.

Conveniently, Bismuth supports both workloads and you can learn more about how we do so in our post that breaks down the architecture of our runtime.

Conclusion

In a nutshell, both Serverless and Microservices offer unique advantages and cater to different aspects of modern application development. By understanding their strengths and differences, you can make an informed decision that aligns with your project goals and resources. Embrace the paradigm that fits your needs, and happy coding! I hope you found this comparison useful and informative. For more tech musings and deep dives, stay tuned to our blog.