Curious about microservice architecture? We explain what microservice architecture is, and how it can be used to quickly produce reliable lightweight applications.
What is Microservices Architecture?
Microservice architecture is a style of development that creates single function services, coupled loosely, that function as part of a larger, complex product. Each service is autonomous so that services can be updated without redeploying the entire application.
Each microservice serves a purpose for the overall product, and each can be written in a different programming language using different technology stacks. Microservice architecture requires minimal central management. Separate teams work on each microservice and manage their specific application throughout the software development lifecycle (SDLC). This makes it easier for teams to build, manage, and deploy their applications because they can act with more independence and agency.
Differences Between Monolithic and Microservice Architecture
To understand the microservices architecture better, let’s compare it to a monolithic application — an application developed as a single unit. Most monolithic applications have three main parts:
- A database consisting of multiple tables, mostly a relational database system.
- A server-side application that handles HTTP requests, retrieves, and updates data from the database.
In a monolithic application, users interact with the presentation layer, the software extracts information from the database, and then results are sent back to the end user. For the most part, it’s an efficient system. However, monolithic applications are limited in functionality and are not as scalable as microservices. For example, any changes to the system requires building and deploying a new version of the server-side application.
Traditional software development processes such as waterfall and agile are usually used to create monolithic applications. Typically, creating a monolithic application is easier than a microservice architecture since it only requires expertise in one language and architecture.
Characteristics of a Microservices Architecture
In a microservice architecture, the application is divided into various components. Each competent is built, deployed, updated, and redeployed independently, and they communicate with each other by sending requests.
For that reason, any issue with one microservice does not compromise the integrity of the others. The downsides of using a component-based structure include increased complexity, expensive remote calls, and coarse-grained remote APIs.
Built around Business Capabilities
Contrary to a monolithic application, microservices are usually specialized based on the capabilities of your team. For every business goal, there is a designated team designed to manage and achieve the goal, meaning business functions drive how teams and services are structured. In a traditional monolithic development approach, the organization consists of several teams, each specializing in a specific area such as user interfaces, front-end development, databases, and server-side. A microservice architecture, on the other hand, operates with teams consisting of cross-functional roles, and each team is responsible for creating individual services and products. Each team handles all of the necessary components for a particular product.
Decentralized Governance and Databases
Microservices architecture favors decentralized governance and data management. Decentralized governance allows developers to build various components of software using their own technology stack, which could be unique. Their tools are selected and configured in such a way that they can be reused to address repeating tasks and procedures. Similarly, each microservice usually manages its own databases instead of having a single logical database used across various applications. No matter how each microservice is built, it can share these resources. This allows customization without needing to spend time rebuilding or reconfiguring these assets.
Resistance to Failure
Microservices are built to contain and cope with failure. When several services are communicating with each other, the possibility of an issue increases. Due to decentralized governance and data storage, the issue is contained in the service from where it originated.
Additionally, since microservices can use third party services as a component, they must be designed to tolerate any service failure. The unavailability of a supplier might cause a service call to fail and the client must respond gracefully, which is a drawback. To cope with this issue, the team must constantly reflect on how failure affects their user experience. Furthermore, it’s vital to detect failure early and automatically restore service (whenever possible). Monitoring microservices is an excellent way to gain visibility into the health and state of your service and prevent the risk of an incident.
Communication between Microservices
Routing or communication between services is a major concern in microservices architecture. The communication between microservices is similar to that of a classic UNIX system that receives requests, processes them, and generates an appropriate response. Unlike ESB (Enterprise Service Bus) which utilizes sophisticated routing facilities, microservices make use of smart endpoints (to processes information and apply logic) and dumb pipes through which the information flows. This allows greater diversity of how microservices are built, as each service doesn’t need to orchestrate unique connections between every pair.
Microservices architecture boasts an evolutionary design that’s ideal for systems where you cannot anticipate the requirements upfront. Dividing the application into various components enables developers to control changes without slowing down the development process. Alternatively, in a monolithic application, change is not as easy to implement and sometimes requires redeploying the entire application.
Benefits of Microservices Architecture
Microservices are deployed independent of each other, which makes them agile (adaptable and open to change). It’s easier to manage the microservices, fix bugs, and release new features. To update one service, the entire application does not need to be redeployed, so it’s a much smoother process.
It’s easier to scale microservices applications as the demand increases. Services are scaled independently and you can supply more resources to scale subsystems without having to scale the entire architecture. Microservices aren’t just easier to scale, but also faster and more cost-efficient.
A great way to manage microservices and containers at scale is via a container orchestration tool such as Kubernetes or Azure Service Fabric. When calibrated properly, it can automatically scale individual microservices by increasing processing power and setting up new instances of microservices as needed. Organizations can save a lot of cloud server resources by scaling only the services that need it.
Reduced Downtime via Fault Isolation
Fault isolation means that even if there’s a fault in one service, the rest of the application is up and running without any issue. Each service in a microservice architecture works independently of each other. The fault is isolated and does not lead to cascading failures causing the entire app to crash. At least, that’s the goal. Since the services are designed to handle failure efficiently, the downtime is reduced.
Flexibility in Choosing Programming Language and Technology Stack
In a microservice architecture, each team can pick up the programming language and technologies that best fit their service. Using a mix of technology stacks keeps teams adaptable and allows them to select languages that best fit their particular requirements.
Easier to Build and Maintain
Applications that are split into smaller units are usually easier to build and maintain. Each service is maintained independently by a separate team. Since each team can deploy, update, and redeploy services without contingencies and dependencies on other teams, they work a lot faster.
Smaller Codebases are Easier to Manage
In a monolithic architecture, the codebase becomes tangled and difficult to manage. Over time, the code dependencies tend to grow, and making any change to one part of the code impacts others too. Since the microservices do not have a shared codebase and the data is stored independently, there are minimal dependencies and changes to one service that don’t impact others. This makes it easier to debug and expand code, as you don’t need to understand the entire codebase.
Autonomous and Cross-functional Teams
New services in a microservice architecture are deployed as needed and independent of each other. A particular team builds and manages a specific microservice without having to worry about the rest of the application. Usually, small and focused cross-functional teams build, test, and deploy the service instead of a large team. This allows them greater autonomy and agency. They can make decisions that suit their service best without needing to worry about how it will impact other microservices.
Drawbacks of Microservices Architecture
The microservices architecture comes with its own drawbacks that you’ll want to consider before you decide to adopt it. To clarify, its benefits outweigh the drawbacks (at least in my opinion), but it’s always good to do your research and consider what’s optimal for your team. Here are some of the common challenges of microservices architecture.
Distributed Systems are More Complex
Unlike monolithic applications, a distributed system is complex. Some complexities include:
- Communication between the services is complex. Generally, there are dozens (or even hundreds) of services working together that need to communicate with each other. You need to build smart ports in each microservice that can parse incoming data, plus infrastructure to communicate that data.
- Debugging is a challenge in itself. With multiple microservices, complete with their own data and logs, debugging (tracing the source of a problem) can be much more difficult when responding to a general outage.
- Testing is more difficult in a distributed environment. With various components and developers, unit testing may be easy on an individual microservice, but integration testing is not.
More Services Means Resources
Microservices usually require extra resources as compared to traditional services. Each service requires its own CPU and runtime environments. Additionally, due to lack of uniformity, each microservice will have its own servers, tools, and APIs associated with it. The services would also use different programming languages and technology stacks, requiring more resources and people.
Microservices architecture has the potential to be more expensive compared to traditional architecture. There are upfront expenses including hosting, security, and maintenance support that require specialized teams. If an org isn’t closely watching these functions, the costs could go up very quickly. It’s in your best interest to pay attention to what services you turn on. For example, consider “size of server” (infrastructure) and be sure to take advantage of preferential pricing. Be careful not to “over-size” and thus allow costs to run high very quickly. Make sure to consider these factors, especially as you scale.
Microservices are a great option for large companies, but for smaller companies and startups, they may be more complex and take longer to implement. Introducing microservices architecture into your organization requires cultural changes. Having a mature DevOps culture in place can make the transition a lot easier.
The first step is to secure buy-in from the engineering executive team. This involves wider education on the long-term merits of taking a microservices approach and how it will ultimately help grow the business. Securing buy-in from c-suite executives, even to the board level in some cases, will ensure that you have full support every step of the way. It’s a “fork in the road” decision, and once you go down the path, it’s hard to turn back. Additionally, you will need to hire and train the right engineering talent to build, run, and maintain.
Additionally, since different teams will be working in different microservices, every team will be independent and lack big-picture visibility. The separation between the teams can lead to a communication gap if not handled efficiently.
Microservices Architecture Use Cases
Microservices architecture is widely adopted by many leading tech companies including Netflix, Amazon, eBay, Spotify, and Uber. Among the early pioneers of microservices are Amazon and Netflix. Most companies that are currently using microservices started out as monolithic applications. Eventually, they moved towards microservices architecture when they needed to scale further. It’s an excellent way to develop and maintain large, complex applications that require multiple business functionalities to work in unison.
Microservices Architecture in SRE
Today, SRE is an integral part of any organization. The term SRE (site reliability engineering) was coined by Ben Traynor and it introduces the idea of treating operations as a software problem. The need for SRE arose from the fact that development and operations used to be siloed, which led to numerous issues.
Even though the role of SREs remains fairly consistent regardless of the architecture type, it does get more complex with a microservice architecture. A microservices application has various components. Collecting metrics such as latency and service response times is more challenging. It’s not always clear how these metrics translate to the individual state of microservices and exactly which microservice is causing the issue. Having multiple sources also means that there are separate logs from each service, introducing some challenges around collecting and aggregating data. Teams have to be more thoughtful when adopting monitoring and observability tooling to proactively watch and debug when things go wrong.
On top of that, microservices are often deployed with the help of container orchestration tools that add more layers to the stack. Those layers increase the risks and complexities that must be managed. Finally, individual services are updated at different times making it difficult to keep track of the overall state of the application.
Although microservices can make SRE more challenging, SRE is still your best approach and practice in making your service more reliable. Here are some examples of how:
- SLOs make the impact of incidents on customers universal, no matter which microservice caused the issue.
- Incident retrospectives help you understand and improve the complexities of the architecture when something goes wrong.
- The blameless culture of SRE helps avoid microservice teams pointing fingers when there’s faults and allows you to make meaningful change faster.
How Can Blameless Help?
We hope that the article was helpful and answered your questions about microservices. The ultimate goal of running a business, whether using microservices architecture or not, is to keep customers happy by providing the best digital experience. Blameless is a one-stop shop for incident response and reliability management, with integrations that connect to your current tool stack and allow you to stay focused on improving service reliability. To learn more about our services, schedule a demo.