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Now please welcome Sebastian!
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Cool! So, hi! I'm excited to be here today with you guys.
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My name is Sebastian. I am from Colombia and I live in Bogotá, which is the capital.
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You can find me as @sevasoga on Twitter and GitHub. I work mainly in backend development.
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I work for a startup called Ride I at Space in New York, although I work remotely. We're trying to reinvent the way people commute.
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So far during this conference, we've heard really interesting talks about Trailblazer, Bolt, and Lotus.
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Well, we almost heard about Lotus, and right now I'm going to talk about microservices.
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Microservices relate to solving common problems at the application level, but my talk will focus on a system design level.
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I call this talk 'Microservices: A Bittersweet Symphony' because, while I really like microservices, I am aware they are not perfect.
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There are many downsides that we will discuss.
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Before we get into what microservices are, I want to share a story.
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This is a story about my first job at a stadium. It was a simple job where I sold hot dogs on game days, and surprisingly, I was good at it.
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My manager decided that, in addition to selling hot dogs, he wanted me to sell foam fingers.
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So I said, 'Okay, that makes sense. I'll do it.' Then he thought I should also announce substitutions during games.
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That was a strange request, and I hesitated, but I went along with it.
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Eventually, my manager lost an employee who mowed the lawn, and I was asked to take on that task.
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I agreed, thinking it would be extra money. Suddenly, I had multiple responsibilities.
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Soon thereafter, my manager asked me to help accommodate guests, and I felt overwhelmed.
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I didn't know how I could possibly handle all of these tasks, but I reluctantly accepted.
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To illustrate my point, I used an image of One Direction which was the best I could find.
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Ironically, One Direction showed up, and I was tasked with accommodating them. It was a bit too much for me.
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Feeling exhausted, I eventually decided to quit because I couldn't handle all the responsibilities.
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So, that's the end of my story. You probably realize by now that this is a made-up story, but I want to emphasize a point.
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Let me ask you: how many of you have a system that you'd like to break down into smaller components?
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Please raise your hands.
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It's great to see that most of you raised your hands, indicating that you might be working with monolithic applications.
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For those of you who didn't raise your hands, if you're not working with monolithic applications now, you probably will in the future or have in the past.
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So what exactly is a monolithic application? Simply put, a monolithic application is the simplest way to build an application.
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Unfortunately, over time, they often turn into a big ball of mud, primarily due to poor object-oriented design.
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As new features are added, the amount of poorly designed code increases and eventually causes the application to slow down.
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The real issue with this type of application is that they become tightly coupled.
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Things might start off well, but inevitably you'll hit roadblocks when you realize the system is too convoluted.
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At that point, rewriting the application or quitting might seem like the only viable options.
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This is where microservices come into play. Now let's discuss what microservices really are.
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I'm sure many of you already have some ideas. Who would like to provide a definition?
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Almost, that's close! Who else wants to define microservices?
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Yes, you're right! Microservices refer to small services that work together, and they can be independently deployed.
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A common question arises: Are microservices just a form of service-oriented architecture? The answer is yes.
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However, service-oriented architecture deviated from its initial focus on separation of concerns to discuss aspects like communication protocols.
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This led to a loss of sight regarding the main ideas, which microservices aim to reclaim.
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Microservices are not a newer concept; indeed, many ideas have been practiced by companies for over a decade.
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They just didn't have a specific name until relatively recently.
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I find the name 'microservices' a bit unfortunate because it implies a focus on size, which isn't the most important aspect.
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The main question is: How big does a service need to be to be considered a microservice?
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Some people say it should be less than a hundred lines of code, but measuring in lines is an unreliable metric.
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Additionally, standards vary between programming languages.
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A common suggestion is that a microservice should be small enough to be built by a small team.
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A famous concept from Amazon states that a team should be no larger than what two pizzas can feed.
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Another way to determine if something qualifies as a microservice is to ask yourself if you would retain it or change it if you had the opportunity to extract it.
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If you decide to leave it as it is, then it likely qualifies as a microservice.
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However, if you would extract multiple components, it likely represents a monolithic application.
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Now, how can we achieve building microservices from monolithic applications?
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Ironically, you should start with the monolith. I wouldn’t recommend starting from scratch with microservices.
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It's often unclear what the microservices need to be, so allow the system to dictate its own components.
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It's crucial to get the design right. If you cannot design a monolithic application effectively, your attempt at microservices will be flawed.
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There are resources like SOLID principles that help create reusable and loosely coupled components.
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However, microservices have considerable operational costs, and you should not overload small teams with these responsibilities.
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To reiterate, designing an architecture is not an easy task, and over time, as complexity grows, the architecture must adapt.
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Logic boundaries matter: understanding where one responsibility starts and another ends is essential.
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Using principles like package creation helps determine how to group responsibilities effectively.
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Ultimately, microservices can help manage complexity better, but they don't remove it, and knowing where complexity lies is crucial.
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A common pitfall is thinking that moving to microservices will solve all your design issues. Good design principles must be established beforehand.
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Migrations to microservices won't solve your underlying structural problems; they may even exacerbate them.
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Microservices introduce new challenges, such as inter-service communication and failure management, which need to be addressed.
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Working with microservices means being ready for failures, as systems will inevitably experience outages or delayed responses.
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Your architecture should provide resilience strategies, like retry mechanisms, to ensure a smooth user experience.
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When building systems, consider the CAP theorem: ensuring you have the proper balance between consistency, availability, and partition tolerance.
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You must also gather and manage logs across multiple services since debugging can become a cumbersome task.
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Finally, be sure to leverage available tools and platforms that support microservices like cloud providers or container orchestration.
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In conclusion, microservices can effectively mitigate complexity in systems, but they demands thoughtful implementation.
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Emphasizing modular design, independent components, and well-defined responsibilities can lead you to a scalable solution.
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When assessing whether to adopt a microservices architecture, ask yourself what complexity you can appropriately manage.
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If you believe microservices will help you achieve better distributed solutions, consider adopting them.
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Remember, there will always be complexity in your system; ensure the architecture you choose effectively helps manage it.
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Thank you!
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Does anyone have questions?
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You mentioned you shouldn't share databases between microservices; can you elaborate on the problems that arise?
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The issue arises at all levels. For example, constraints like that a field cannot be nil may not align between different services.
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Additionally, model validations can conflict, leading to breaches in encapsulation.
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So the main problem is breaking encapsulation by sharing a database.
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What’s your preferred method for inter-service communication, sending requests or events?
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It really depends on the context. For some apps, like mobile or web apps, synchronous requests are necessary.
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However, I recommend making components asynchronous when possible, as this can help better manage failures.
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So, while synchronous requests have their role, my advice is to lean towards asynchronous patterns.
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How do you deal with asynchronous programming in Ruby for communication between services?
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We use various methods, including a message broker. For instance, we commonly use RabbitMQ.
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We put messages or payloads into the broker, allowing for a transactional model that continues to function even during failures.
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If one service goes down, messages held in the queue are not lost, ensuring resilience.
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On a related note, how do you manage sharing code between different microservice repositories?
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Instead of sharing code, I recommend creating a new microservice that encapsulates shared behaviors. That way, all microservices can use those behaviors without duplicating code.
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This also aids in managing complexity as you promote more cohesive service-oriented design.
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What are your tips for orchestrating synchronous transactions in asynchronous architectures?
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We have scripts that manage processes through event triggers, enabling effective orchestration.
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It requires careful design, but it can work, though it's not particularly elegant.
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Could you elaborate on how RabbitMQ could potentially create a single point of failure?
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Yes, single points of failure can be a concern. However, we manage this by using replicated instances of RabbitMQ.
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In the event one instance goes down, the others take over without disrupting the overall communication.
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While this is a valid concern, we are prepared with a proper architecture to avoid such situations.
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Thank you for your questions, and I appreciate the engaging discussion!