Definition: What Are Microservices?
Microservices are a software architecture that allows developers to independently build and deploy individual components of a more extensive application. It means each component can be updated or changed without affecting the other parts of the app.
Microservices are often used in cloud-based applications, where they can take advantage of the scalability and flexibility of the cloud. They can also make it easier to manage complex applications by breaking them down into smaller, more manageable pieces, each assigned to small, independent teams.
A microservices architecture may be the right choice if you’re looking to create a scalable, cloud-based application.
How They Work: Essential Characteristics of Microservices
The core idea behind microservices is to break down a larger application into smaller modular pieces that can be developed, tested, and deployed independently. This functionality improves the ease and decreases the cost of maintaining microservices as new features are developed.
However, as each service runs autonomously, they must be brought together. Here the APIs work as the thread that ties them together. When connected, the microservices form a larger system that can be easier to manage and maintain without losing sight of how individual pieces fit together.
Developers today use cloud servers like Amazon AWS and container orchestration tools like Kubernetes to run microservices. These tools enable developers to efficiently allocate processing power as required without overcoating their resources in workforce or cost.
In whatever way microservices are developed and deployed, they must have the following characteristics:
Independent and Self-Contained
Each microservice, when developed and deployed, should be able to solve a business need independently. While that’s usually not the case due to dependency among microservices, the idea is to have the dependency to the minimum. That way, a microservice can function as a standalone application.
Moreover, each microservice should have its own team. The team working on the microservice should be small in size but possess all relevant skills to deliver a solution end to end. The aim behind a smaller team size is to improve communication and collaboration and increase the solution delivery speed.
Components Communicate With Each Other
The foundation of microservice communication is built around the same protocols that Unix is built on. Microservice components communicate with each other through HTTP requests-response (usually served through APIs). However, microservice architecture advocate the idea of dumb pipes and smart endpoints.
Instead of having a complex communication structure like an Enterprise Service Bus (ESB) that is capable of message routing, transformation and business rule application, microservice communication structure should have a lightweight message bus which is dumb. It should only provide reliable asynchronous communication.
Microservice endpoints, on the other hand, should be smart enough to consume the right message and apply appropriate business rules to produce relevant messages.
Microservices are modular in nature. That means, if multiple changes are made to a microservice, only that microservice should be redeployed. Moreover, a microservice should be replaceable with another microservice without affecting the overall system.
However, in case a microservice has multiple dependencies, changes should be minimally incremental to avoid entire system failure.
Whenever the demand for a microservice increases, it should be independently scalable. The infrastructure that supports the microservice should be able to downsize or upsize automatically and independently based on its demand. Containerization and container orchestration tools can come in handy for such use cases as they assign processing power as required and reduce cost and resource needs whenever possible.
Updated Without Affecting The Rest Of The Application
Any updates made to a microservice should not affect other parts of the application. In fact, if a microservice fails, other components should be able to function independently of the failure.
Microservice community advocates decentralized governance – delegation of authority around tools, processes, and programming languages from central management to respective teams.
Because microservices are distributed, it should be easier for organization working with microservices-based architecture to promote decentralized governance. The central management only has to think about standards while each microservice team has the autonomy to decide the specifics.
For example, the central management could set a global standard that every engineering team must use linters to format their code. However, an engineering team could choose to use tab for spacing while another could choose spaces. Similarly one team could choose to use C++ for programming while others could choose Python, provided they can solve a business problem.
Moreover, this autonomy should extend to data management. Unlike traditional architecture where a single data store or database is present, every microservice should be able to choose the best data store for itself.
Benefits: Why Use Microservices?
There are several benefits of using microservices application architecture.
Loosely Coupled Services
Loosely coupled services imply that other services that depend on a microservice don’t need to understand how they are integrated. The changes to one microservice’s design, implementation, or behavior don’t require a change in another. In other words, microservices are not largely plagued by dependence, which decreases the time and effort required for testing and integrating incremental changes made to a microservice.
Each microservice is a standalone application; it can have its own technology stack and a separate database system. This independence boosts the productivity of the team and solution delivery speed.
Higher Fault Tolerance
In a microservices architecture, each component is its own self-contained service that can be deployed, updated, and scaled independently. This means that if one service fails, the others can continue to run, providing excellent stability and uptime for your system. This feature, in turn, supports the trust and loyalty of your customers.
However, there might be cases where a microservice has to depend on other microservice(s). In cases where microservices architecture has many dependencies, it’s important to protect the application from dependency failures that may occur due to its core functionality becoming unavailable. One of the ways we can overcome this problem is through infrastructure monitoring by collecting metrics and events.
Easy To Maintain And Test
Microservice applications are easy to test, deploy and maintain because:
- The term microservice refers to an application divided into the smallest unit of feature and functionality. Since a microservice is small, the team required to test, develop, and maintain microservices can be small too. For a business, this means higher productivity and solution delivery speed.
- Microservices provide functionality in complete isolation from other microservices. So, testing a microservice without worrying about dependency on other microservices is easier.
- A microservice has its own features and behavior around business capabilities, making it more predictable and testable. The resulting application that follows microservice architecture is highly maintainable.
Focus On Business Logic
Teams working on microservices are separated to solve a business requirement. They don’t have to worry a lot about the uniformity of the technology layer.
When you have a monolithic application, the business must focus on gathering resources that work with the existing technology stack, which can turn into a challenging task. However, each team can work on a different technology stack in a microservices-oriented architecture. Technology stack is no longer an issue as much as a business problem.
This ability provides organizations with greater agility to respond quickly and positively when it comes time for new features or changes.
Faster Development Cycles
Microservice community advocates the idea of Minimum Viable Product (MVP) as microservices are modular in nature. Developers can quickly craft the core logic of the application and ship the functionality to the market. The increase in development speed decreases the time to market. Once the core features are deployed, developers can then incrementally enhance the application with exceptional agility.
Moreover, microservices are independent in nature and the team working on them are smaller in size. Hence, teams can integrate their microservices into an existing infrastructure swiftly with low chance of failure and conflicts.
With microservices, organizations can quickly implement new business models and adapt to the changes in the market. Microservices decrease the time to market and cost associated with development – the two major barriers for innovation.Teams can quickly develop the MVP through microservice and deploy it.
In addition, microservices can be smoothly decoupled from a system and replaced with the new microservice without affecting the uptime of the system. They also reduce the time for testing as microservice have a smaller domain.
While microservices have many benefits, it has its own sets of disadvantages.
Complex Inter Component Communication
Even though every microservice is decoupled from each other, some form of synchronous or asynchronous communication between microservices must ensure the business logic and infrastructure are correctly functioning.
The challenges lie in scenarios when a service needs to communicate with a faulty service where things like retries and circuit breaking need to be handled. If handled incorrectly, the communication between such microservices can be quite chatty and cumbersome on the available resources.
So developers need to create a safety net around handling such scenarios through retry limit or timeout controls. Alternately, they could also enforce mechanisms like circuit-breakers that trigger for a particular duration. During that period, any request to the faulty service will immediately fail saving the cost of communication with faulty service.
Higher Resource Utilization
Each microservice in a microservice architecture has its own computing and storage capacity. It could require multiple databases and transaction management. This, in turn, can result in duplication of effort. Moreover, developers must be aware of measures to mitigate fault, improve network latency and deal with load balancing.
Complex Initial Configuration
Initial deployment of microservices is usually complex because each service can have its own set of configurations and requirements. The DevOps team must ensure that all the microservices are tied together with proper configuration. In return, this will help them ensure that the system can deal with the complexity of a distributed system, since microservices are essentially distributed systems.
Difficult Testing, Logging, And Monitoring
The microservices-based architecture will result in a number of different microservices. Integration testing can turn into a complex job when working with numerous microservices. One of the major challenges in microservice testing is finding chain reaction errors. An error occured in a microservice can trigger a chain reaction inside multiple microservices, making it harder to catch the initial error.
Each microservice also has its own logs that you could choose to monitor manually. But manually monitoring each microservice issue through its logs can become tedious. Hence, the logs of every microservices should be centralized via a log management software. However transitioning to a centralized log management software has its own sets of challenges like log analysis, storage, and processing.
What Are the Differences Between a Microservice Architecture and Other Software Architectures?
In addition to Microservice Architecture, there exists different Software Architectures. However, each of these Architecture have their own benefits and characteristics.
Monolithic vs. Microservices Architecture
Monolith architecture is the approach to designing software systems with a single composed unit. A composed unit means a single backend that handles all the business services. It also means all components are tightly coupled, and changes to one component can impact other application parts.
Furthermore, assets within monolithic applications have limited reusability. The reusability is most often limited within the scope of the application. If an application outside the monolithic application wanted to use monolith’s asset, the solution can often be challenging.
On the other hand, a microservices architecture is built as a set of independent microservices that communicate with each other. This makes it much easier to make changes to individual microservices without affecting the rest of the application. Microservices are also reusable and sharable, which decreases the cost of development and boosts accountability.
However, microservices can be more complex to manage than a monolithic architecture. If you’re wondering which architecture is better, the answer is: “It depends.”
When is Monolith architecture the right choice?
- If the application is straightforward and simple and doesn’t have multiple components working together.
- If the business requirements can be handled by a single server or multiple server instances of a single service, there is no future burden of having to scale to millions.
- A team of a few developers (usually less than 10). Unless there is a plan to expand the development and DevOps team, monolithic architecture should work in most cases.
When should you use a Microservice architecture?
- If there are requirements to serve a large volume of traffic, it is much better to go with microservices. Vertical scaling is much harder for a monolith service handling large volumes of users concurrently.
- Horizontal scaling with load balancing multiple instances of a single service server still fails to solve the issue of concurrent database access bottleneck. On the other hand, microservices are easier to scale for increased data usage because each service has its own database.
To sum up, a monolithic architecture may be a good choice if you have a small application that doesn’t need to be changed often. A microservices architecture may be a better option if you have an extensive application that needs to be updated frequently.
Microservices vs. SOA
Service-oriented architecture (SOA) is an approach that takes advantage of reusable components, where each component serves a specific business need. While microservices were inspired by SOA, the two differ in many ways.
- Microservices have application scope, whereas SOAs have enterprise scope.
- Microservice components are generally more loosely coupled and disposable than their predecessors — even if it means not having any dependency.
- Microservices have a lower level of dependency between each unit or component within the architecture.
- Microservices are an architectural approach that can operate in the cloud on containers, making them more portable for creating independent services.
- SOA uses SOAP (Simple Object Access Protocol), AMQP (Advanced Messaging Queuing Protocol), and MSMQ (Microsoft Messaging Queuing), but microservices use HTTP/REST (Representational State Transfers) and JMS (Java Messaging Service).
- SOA relies on ESB (Enterprise Service Bus) for synchronous communication, and if there is a failure in ESB, the entire application can fail.
All said and done, SOA is a better choice when building large applications requiring synchronous communication. Microservices are better when building relatively small applications that work with asynchronous communication.
Microservices vs. Web Services
Web services are an internet-based interface that allows a service to communicate with others. In comparison, Microservice is a software architecture. Simply put, web services allow microservices to communicate, interoperate or exchange data.
Both web services and microservices are used to build application architectures, but there’s a primary difference in how they work.
Microservices are modular and service-oriented, and they often connect with the help of APIs (a type of web service) so that other applications can be easily integrated with them. However, web services applications comprise the architecture that allows different components to connect via web services. Using web services, developers can connect microservices and monolithic applications to work together as a more extensive program.
While microservices are primarily used for reliable and scalable applications, web services are mainly used to facilitate communication and data exchange over the web.
Microservices vs. Containers
Containers make it easier for organizations to share resources like codebase between multiple machines or even different cloud platforms within one company’s infrastructure without downtime. They allow you to update applications quickly and efficiently with new code without fear of breaking existing functionality. This means faster innovation.
The difference between microservices and containers is quite straightforward. While microservices are about software design and development, containers are packaging software for deployment. You can use a container to host your microservice or get a better value by running microservices within containers. By spreading the microservice application into multiple containers, you can provide resilience and agility to the entire application.
The advantage of using microservices for a company’s daily operations is that it can help you be more efficient. That’s why many companies use microservices to scale the operational efficiency and keep the product running even if something goes wrong in one component.
Netflix has a complex architecture. They use microservices to modularly implement their solutions and make them easier for developers of various skill sets to work on different parts simultaneously. Netflix migrated their movie-encoding segment of the application to microservice architecture first, followed by customer-facing elements like new user sign-up and configurations.
It shouldn’t come as a surprise that the company powering most of the microservice applications is itself based on microservice. Amazon uses microservices to power its eCommerce platform. Furthermore, Amazon pioneered the idea of a small, dedicated team working on a particular service.
When Uber started using microservices, it improved performance and smooth business operations. With exponential growth across the board in terms of volume as well as size, minutely processed data became an issue for this company. So, Uber divided the entire application into multiple microservices. Once the application was divided, Uber was able to enhance the performance of their application and, at the same time, quickly deploy changes to keep up with their growth.
Spotify moved to microservice-based architecture 75 million users later. The company runs hundreds of microservices that are easy to scale and test. Specialists work on these microservices to ensure everything runs smoothly behind the scenes without anyone realizing what goes into making those decisions.
Like Spotify, eBay migrated to microservices-based architecture when it had 97 million active users. Today eBay works with 1000+ microservices, and they have an independent team working on each of these microservices. It lets those microservices work independently and for a good reason. They have been able to address the growing demand of their user base efficiently.
Microservices Monitoring with Sematext
Microservices monitoring may be challenging, but this is easy to overcome if you use full-stack monitoring tools like Sematext Cloud.
Sematext monitors any environment you choose to run your microservices on, whether it’s bare metal machines or containers managed by orchestration tools like Kubernetes. It integrates with a number of notification channels, including Email, Slack, and PagerDuty, to alert you whenever something goes wrong like CPU above a threshold, anomalous network throughput, and many more.
The tool has service auto-discovery to help monitor new instances or stop monitoring old ones. Together with the flexible pricing model, the infrastructure can autoscale without you worrying about blindspots or huge bills.
Further, Sematext gives you visibility beyond infrastructure performance and into all the technologies involved, providing metrics such as JVM-level metrics or custom, application-specific metrics. It comes with out-of-the-box dashboards for each supported technology and tips to explain what metrics mean and what you can do when values are too high or too low.
Last but not least, you’ll want to aggregate logs from all instances of all microservices. By discovering new logs automatically, aggregating them is just as easy as collecting metrics. You can visualize logs alongside metrics and get alerted on anomalies in the same way.
Try it and see for yourself. There’s a 14-day free trial available for you to test all its functionalities.