What is SOA?

SOA is an architectural pattern in computer software design. In this type of application, components provide services to other components via a communications protocol, typically over a network. The principles of service-orientation are independent of any product, vendor, or technology. The full form of SOA is service-oriented architecture

SOA makes it easier for software components over various networks to work with each other.Web services that are built as per the SOA architecture tend to make web services more independent.

In this tutorial, you will learn:

What is Microservices?

Microservices is a service-oriented architecture pattern wherein applications are built as a collection of various smallest independent service units. It is a software engineering approach that focuses on decomposing an application into single-function modules with well-defined interfaces.

These modules can be independently deployed and operated by small teams that own the entire lifecycle of the service.

The term "micro" refers to the sizing of a microservice which must be manageable by a single development team (5 to 10 developers). In this methodology, big applications are divided into the smallest independent units.

What is SOA Architecture?

Service-oriented architecture is a style of software design. An architecture is categorized into two parts

  1. functional aspects and
  2. quality of service aspects.

Let see both of them in details:

SOA Architecture

Functional Aspects:

The functional aspect contains:

Transport: This component transports the service requests from the service consumer to the service provider and service responses from them to the service consumer.

Service Communication Protocol: It allows the service provider and consumer to communicate with each other.

Service Description: It explains the service and data required to invoke it.

Service: It is an actual service.

Business Process: This component represents the group of services called in a certain predefined sequence associated with the specific rules to meet the business demands.

Service Registry: This registry contains the description of data that is used by service providers to publish their services.

Quality of Service Aspects:

The quality of service contains:

  • Policy: It is a set of protocols according to which service providers create and provide services to consumers.
  • Security: It represents the set of protocols needed for the identification and authorization process.
  • Transaction: It provides the surety of consistent results.
  • Management: This component of SOA helps you define the set of attributes which are used to manage the services.

What is a Microservice Architecture?

It is an architectural development style that allows building an application as a collection of small autonomous services developed for a business domain.

It is an architectural development style that allows building an application as a collection of small autonomous services developed for a business domain.

Let's take an example of an e-commerce application developed with microservice architecture. In this example, each microservice is focused on single business capability. Search, rating & review, and payment each have their instance (server) and communicate with each other.

Microservices Architecture Example

In this Monolithic Architecture, all the components coalesce into a single module. But, in Microservices Architecture, they are spread into individual modules(microservice) which communicate with each other.

The communication between microservices is a stateless communication where each pair of request and response is independent. Hence, Microservices can communicate effortlessly. In the Microservice Architecture, the Data is federated. Each Microservice has a separate data store.

Features of SOA

Here, are important features of SOA

  • SOA uses interfaces that solve the difficult integration problems in large systems.
  • SOA communicates with customers, providers, and suppliers by using the XML schema.
  • SOA uses the message monitoring to improve performance measurement and detects the security attacks.
  • As it reuses the service, so the cost is slightly lower for software development and management.

Features of Micro-services

Here, are essential features of Microservices:

  • In Microservices modules are the loosely coupled
  • Management of the project, can also be modularized.
  • Cost of scalability is meager
  • It's very easy to use multiple technologies as multiple features in an application.
  • It is an ideal service for evolutionary systems where you can't anticipate the types of devices which may one day be accessing your application.

Microservices vs. SOA: What's the Difference?

Here are differences between SOA and Microservices:

SOA Microservices
SOA model has a single data storage layer which shared by all of the services in that application. Microservices apps mostly dedicate a database or other type of storage to services that need it.
Communication between different services in an SOA app uses simple and straight forward approaches. Microservices use complex APIs.
Focused on maximizes application service reusability. More focused on decoupling.
A systematic change requires modifying the monolith. A systematic change helps you to create a new service.
DevOps and Continuous Delivery are becoming popular but yet not become mainstream. Strong emphasis on DevOps and Continuous Delivery
Full-stack in nature Monolithic in nature
Supports multiple message protocols. Uses lightweight protocols like HTTP, REST, or Thrift APIs.
It is designed to share resources across services. It is designed to host services that can function independently.
Frequently involves component sharing Typically, it does not include component sharing
Involves sharing data storage between services Each service can have independent data storage.
Better for large scale integrations Better for small and web-based applications.
Communicates through an ESB Communicate through an API layer
Relies on sharing resources Relies on the bounded context for coupling.
Less flexibility in deployment Quick and easy deployment.
The technology stack of SOA is lower compared to Microservice. Microservice technology stack could be very large.
Business units are dependent. Business units are independent of each other.
An SOA app comprised of two or three services. A Microservices app could have dozens of services.
SOA applications are built to perform numerous business tasks. They are built to perform a single business task.
Deployment is a time- consuming process. Deployment is straightforward and less time-consuming.
Business logic components are stored inside of single service domain simple wire protocols(HTTP with XML JSON) API is driven with SDKs/Clients. Business logic can live across domains enterprise service bus like separate layers between services.
Uses enterprise service bus (ESB) for communication It uses the less elaborate and straightforward messaging system
Software size is larger than any conventional software The size of the Software is small in Microservices
Multi-threaded with multiple overheads to handle I/O Single-threaded mostly use with Event Loop features for non-locking I/O handling
A systematic change needed for modifying the monolith In Microservices, systematic change is to create a new service
Focus on maximizing application service reusability. Emphasis on decoupling.
Common governance and standards. Relaxed governance, as is more focused on people's collaboration and freedom of choice.
The deployment process is time- consuming. Deployment is easy and less time-consuming.
Less scalable architecture. Highly scalable architecture.

Advantages of SOA

Here, are pros/benefits of SOA

  • Editing and updating any service is easy
  • Services have the same directory structure, which allows consumers to access the service data from the same directory every time.
  • Services communicate with other applications using a common language which means it is independent of the platform
  • Services are usually small size as compared to the full-fledged application. Therefore, it is easier to debug and test the independent services.
  • SOA allows reusing the service of an existing system, alternately building the new system.
  • It offers to plug in new services or to upgrade existing facilities to place the new business requirements.
  • You can enhance the performance, functionality of a service, and easily makes the system upgrade.
  • SOA can adjust or modify the different external environments
  • The companies can develop applications without replacing existing applications.
  • It offers reliable applications in which you can test and debug the independent services as compared to a large number of code.

Advantage of Micro-services

Here, are pros/benefits of using Micro-services:

  • Easier architecture pattern which is easy to understand for developers
  • The IDE is faster making developers faster and productive
  • The web container starts faster; this helps to speed up the process of deployments and developments.
  • It allows the team to develop, deploy, and scale their service independently of all of the other teams.

Disadvantages of SOA

Here, are cons/disadvantages of using Service Oriented architecture:

  • All inputs should be validated before it is sent to the service
  • SOA is a costly service in terms of human resources, development, and technology.
  • Some web service needs to send and receive messages and information frequently, so it reaches a million requests per day easily.
  • SOA requires high investment cost
  • There is bigger overhead when a service interacts with another service this will increases the response time
  • SOA service is not suitable for GUI (graphical user interface) applications that so it will become more complicated when the SOA needs heavy data exchange.

Disadvantages of Micro-services

Here, are cons/drawback of Micro-services:

  • It is developed for building monolithic applications, so it doesn't provide explicit support for developing distributed applications.
  • Testing is more difficult
  • Developers must implement the inter-service communication mechanism.
  • Implementing use cases that span multiple services requires coordination between the teams.
  • Microservice is costly, as you always need to maintain various server space for different business tasks

Which Architecture is Better?

SOA is an ideal architecture method for large and complex business applications. It is a most suited for environments that require integration with many diverse applications.

However, workflow-based applications that have a well-defined processing flow are challenging to implement with the help of SOA architecture patterns. Therefore small applications are also not ideal for SOA as they don't require middleware messaging components. On the other hand, the microservice pattern is well suited for smaller and well partitioned web-based systems.

KEY DIFFERENCES:

  • SOA is focused on application service reusability while Microservices are more focused on decoupling.
  • SOA is full-stack in nature whereas Microservices is monolithic
  • SOA applications are built to perform numerous business tasks, but microservices are built to perform a single business task.
  • SOA involves sharing data storage between services while in Microservices, each service can have independent data storage.
  • SOA is designed to share resources across services while Microservices is designed to host services that can function independently.
  • In SOA Architecture, DevOps and Continuous Delivery are becoming popular but yet not become mainstream while Microservices have strong emphasis on DevOps and Continuous Delivery.
  • SOA is a less scalable architecture while Microservices is highly scalable architecture.

 

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