What is microservices test

Microservices

Microservices are an architectural concept of application development. What sets them apart from traditional, monolithic approaches is the way apps are broken down into their core functions. Each function or service can be developed and implemented independently. This means that individual services can function (or not) without influencing other services in any way.

Just remember your last visit to an online shop once. You may have used the product search feature on that site. This function is a service. You may also have been presented with recommendations for related products taken from the buyer preference database. That is also a service. Have you added items to your shopping cart? Exactly, that too is a service.

A microservice is therefore a core function of an application and it is executed independently of other services. The microservice architecture is about more than just linking such core functions. It's about restructuring development teams and communication in a way that acts as preparation for inevitable errors, future scalability, and integration of new features.

How does this work? By adapting the basics of a SOA (Service-Oriented Architecture) for the provision of microservices.


If it sounds familiar ...

that apps are broken down into their core functions in order to avoid problems of monolithic concepts, this is because the architectural style of microservices is similar to the established software design of SOA.

In the early days of application development, even minimal changes to an existing app required a complete version update with its own quality assurance cycle. This, in turn, has severely limited the efficiency of numerous downstream teams. This concept is often referred to as "monolithic" because the source code for the entire app was in an inseparable development unit (such as .war or .ear). So when updates to parts of an app caused errors, the whole system had to be taken offline, scaled back and repaired. Although this concept can still be implemented for smaller applications, the associated downtimes are no longer acceptable for growing companies.

And this is exactly where the SOA approach comes into play, in which apps are structured into discrete, reusable services that communicate via an ESB (Enterprise Service Bus). In this architecture, the individual services organized around a specific business process follow a communication protocol (such as SOAP, ActiveMQ or Apache Thrift) so that they can be used jointly via the ESB. These services integrated via an ESB form an application.

On the one hand, this means that services can be developed, checked and adapted at the same time without any monolithic development cycles. On the other hand, the ESB represents a single point of failure for the entire system. That is, when trying to eliminate a monolithic approach, a new one has been brought into being, namely the ESB, which is a bottleneck for the entire organization can.


From SOA to microservice

What's the difference? Microservices can, usually stateless, together communicate. As a result, microservices based apps are more fault tolerant and less dependent on a single ESB. And because microservices communicate using language-independent APIs, dev teams can choose their own tools.

If you look at the history of SOA, microservices are actually not all that new. However, thanks to advances in containerization technology, their feasibility has increased enormously in the meantime. With Linux containers, you can now run several parts of an app on the same hardware independently of one another, while at the same time being able to control the individual components and lifecycles much better. Together with APIs and DevOps teams, containerized microservices form the basis for cloud-native applications.


What are the advantages of a microservices architecture?

Thanks to the distributed development of microservices, completely new possibilities arise for your teams and routines. So you can develop several microservices at the same time. This means that more developers are working on the same app at the same time, which significantly reduces development time.

Get to market faster

Since the development cycles in a microservice architecture are much shorter, implementations and updates can also be carried out in a much more agile manner.

Highly scalable

If the need for certain services increases, these can be implemented flexibly across multiple servers and infrastructures.

robustness

If these independent services are properly developed, they will not affect one another in any way. This means that if one component fails, the entire app does not go on strike, in contrast to the monolithic approach.

Easy implementation

Since microservice-based apps are modular and much smaller than traditional monolithic apps, you can safely forget about the problems associated with the old methodology. Although the new variant requires more intensive coordination, this fact can be more than offset by the great advantages.

Better access

As a larger app is broken down into smaller pieces, developers can more easily understand, update, and improve the individual components, which in turn leads to shorter development cycles, especially when combined with agile methods.

More openness

Thanks to language-independent APIs, developers can freely choose their preferred language or technology for the required function.


And the challenges?

If your organization is considering moving to a microservice architecture, be prepared that it will not only change the way the apps work, but also the way your employees work. Organizational and cultural changes are considered challenges because each team has its own development processes and is responsible for individual services with its own customer base. These thoughts may not be typical for developers, but they are essential for the success of a microservice architecture.

In addition to the cultural and procedural components, complexity and efficiency are two of the greatest challenges of a microservice architecture. John Frizelle, Platform Architect at Red Hat Mobile, outlined the following eight challenges in his presentation at the 2017 Red Hat Summit:

  1. Development: You need time to identify the dependencies between your services. Note that the completion of a build can trigger several more builds due to such dependencies. To do this, you also need to consider the impact microservices have on your data.
  2. Test: Integration and end-to-end testing can become more complex and important than ever. Note that, depending on how you have structured your services to support each other, a flaw in one part of your architecture can cause problems in another.
  3. Versioning: When updating to new versions, do not forget that this can affect backward compatibility. And even if you incorporate conditional logic, your builds can quickly become cumbersome and inefficient. Alternatively, you could start up several live versions for different customers, but this in turn increases the maintenance and administrative effort.
  4. Implementation: Yes, this point is also one of the challenges, at least with the initial setup. To make implementation easier, invest generously in automation, as the complexity of microservices can be overwhelming to human development. Think about how and in which order the rollout of your services should take place.
  5. Logging: With distributed systems, you need central logs to collect all data. Otherwise efficient scaling becomes impossible.
  6. Monitoring: It is imperative that you have a centralized view of your system so that you can identify the root cause of problems.
  7. Debugging: Remote debugging is not an option here and will not work on dozens or hundreds of services. Unfortunately, at this point in time, there is no satisfactory answer to this question.
  8. Connectivity: Consider a service discovery solution, centralized or integrated.

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