The invention of the Internet has made the world a global village, but it was only possible when someone had seated in front of the desktops or laptops like computing devices. Later on, the introduction of mobiles has made the fragmented world a global village in true meaning by granting mobility and other options for connectivity.
In early days of the digital era, only websites and web applications were serving as electronic shops and were offering limited features and functionality. Therefore, web applications were monolithic in nature means acting as a single unit.
Monolithic Application Architecture
Technically, the monolithic application becomes responsible for all activities or functionality such as handling user inputs like HTTP requests, implementing domain logic, authenticate users, managing databases, and other communication in between various modules accomplishing different tasks, but tightly join with each other.
Ensues of Rapid Progress
Therefore, managing a minor fault or modification involves the entire application and need to build/correct it and deploy the entire system again with each time. It was not much bothersome until the size of the code of application remains within a limit that an IT team of business can work together.
Once the business grows, a number of users also grows, extra services and functions attached to it, and database inflated tremendously. Moreover, in the UX era, expectations of users at performance, usability, and user experiences like fronts grow. It compels business or organization to integrate third-party services to meet all.
With the pace of time, SMBs to enterprises all have started prefer Omnichannel approaches to stay and grow in the market. Mobiles have added additional loads and demanded extra workouts in the monolithic system.
Issues with Monolithic Application & Birth of Microservice Pattern Architecture
Other lacunae come with monolithic applications are:
- The monolithic application is a single unit with a single codebase.
- It is highly complex to maintain, upgrade, and modifications.
- Tough to implement agile development methodologies.
- Demands frequent redeployments.
- Scaling beyond a limit is hard and impossible in some cases.
- The system becomes unstable and insecure.
- Resisting innovation and adoption of upcoming technologies.
Thus, burdens over IT departments in managing monolithic applications has increased. Now, they forced to find a way out for the sake of a better option at software architecture level. Gradually, a ‘Micro Service Architecture’ concept evolved, and became popular as well as got adoption among the giants to mid-level applications.
Remember: SOA (Service Oriented Architecture) is an altogether different thing and applying SOA in monolithic never make it microservice in the true sense.
Let’s see what microservice architecture is and help businesses to expand further from local to global level.
What Is Micro Service Architecture?
It is an assembly or suite of small services glued together/coupled loosely as a whole unit. In simple words, a huge monolithic application can be broken down into several small fragments to work as independent units with all required power and privileges.
There are some obvious advantages and disadvantages of Microservices for startups to big businesses aiming to scale up to world-level operations.
Pros of Microservice Pattern
The main advantages of microservice pattern are:
- Saves You from Touching Core CodebaseSince, Micro service application is a cluster of several independent applications, tweaking the code of one small unit application never affects the operations of the rests of units.
- Deals with Small Codebase Each microservice unit deals with only a single concern it has a little codebase and a few components to plumb like a database. Therefore, developers have to deal with a small codebase in the case of debugging, crash, or modification.
- Quick Scaling of Application Scaling a giant codebase is a tough and costly affair, but a small codebase is easy and fast. Therefore, scaling a microservice application is a non-intrusive and quick experience for a developer.
- Fast Deployment The majority of microservices have limited dependencies, so deployment becomes easy.
Cons of Microservice Pattern
The main disadvantages of microservice pattern are:
- Microservices are depending on each other and need to function in collaboration. It demands complete channel of communication. Therefore, it demands additional tools to accomplish internal exchanges.
- In due course, developers should introduce HTTP APIs because HTTP is a de facto data exchange gateway on the web and anything related to it. Another mode of communication for microservices is relying on messaging queues.
- In the case of mass processing or long-running processes, placing the service request in the queue is an excellent way. In due course, RabbitMQ and ZeroMQ are extremely useful tools/services.
The issue in Service Discovery
- Microservices rely on each other in many instances and need to communicate with each other through APIs or other means, but identifying the required service is an essential step and should take place before communication starts.
- It needs highly available, consistent, and distributed design of application architecture from the app development team.
If you follow some good coding practices and design guidelines for microservices, you can achieve expected results easily. Those special designing concerns are:
- Follow the SRP (Single Responsibility Principle) while designing microservice application by implementing limited and focused business scope for a single unit.
- Go for domain-driven-design with bounded contexts where you have to find boundaries and align those with business capabilities.
- Design should permit agile or independent development & deployment services
- Never misunderstood that microservice means smaller service, instead perceive it as focused on smaller/limited targets for each service unit.
- A microservice should have a few operations, functionality, and simple message format
- The best practice is, to begin with relatively wide scopes at the beginning and to refactor to small units in later stages.
Message Management in Microservice
Microservices demand simple and lightweight messaging solutions to establish seamless communication in between the various components of the service architecture. Therefore, following are best ways, practices, and technologies to implement in designing microservices.
- For synchronous messaging protocol, needs use REST or Thrift APIs to expose microservices.
- For asynchronous messaging protocol, needs use AMQP, STOMP, or MQTT.
- The preferable formats for microservices are:
- JSON and XML are text-based message formats
- Thrift, ProtoBuf, &/or Avro are binary message formats
- Define service contracts using REST API using IDL(Interface Definition Languages) like Swagger and RAML on top of REST API whereas for non-REST/HTTP-based microservices we can use Thrift IDL.
Microservices architecture built as a suite of independent services and process or inter-service communication is vital. Therefore, unlike SOA in the monolithic application, microservices uses several different communication patterns, such as:
Point-to-point styles that invoke services directly
API-Gateway Style to consume managed API over REST/HTTP
It uses a lightweight gateway as an entry point for all communication needs in microservice architecture. Thus, it consumes managed API over HTTP/REST. The main advantages of API-GW are ensuring security, monitoring, and throttling like non-functional capability with a central point it provides required abstraction layer at the gateway point.
Message broker style to manage asynchronous communication
It is based on AMQP & MQTT standards.
Decentralized Data Management in Microservice Architecture
Unlike monolithic architecture where a single and centralized database manages all data related affairs, the microservices architecture uses decentralized and individual database architecture. It gives completely decoupled architecture to implement different types of databases (SQL &/or NoSQL) in a single application.
Decentralized Governance in Microservice Architecture
There are two types of governance used in SOA model, design-time, and run-time. Since microservices don’t need a common standard for service design and development, it eliminates needs of the design-time governance. Thus, it enables microservices to take an independent decision about design & implementation. Run-time governance implemented at API-GW level.
Service Registry in Microservice Architecture
It consists of microservice instances and locations. Microservice instances registering at startup and deregistering on shutdown.
Service Discovery in Microservice Architecture
It helps in finding the availability and location of microservices in the service registry, and that mechanism falls in two categories, client-side discovery, and server-side discovery.
Deployment of Microservice Architecture
Deployment has a critical role in microservice architecture as the process must take place independently from other microservices and save the application in the case of failure or affected during scaling processes.
Docker is an application container in Linux and enables deployment of microservices easily, and Kubernetes extends its capabilities.
Security in Microservice Architecture
Security measures used to implement at the beginning of the request handling chain, and for microservices, it is tough to execute at each microservice level.
Therefore, OAuth2 & OpenID measures at API-GW is the best solution for microservices security.
Ideal Microservices Examples from Big Brands
In practice, there are a number of leading enterprises and online giants who have an Omnichannel presence using microservices as their application architecture and solve their IT problems to a greater extent.
The ideal examples are Walmart, Spotify, and Groupon.
The retail giant was using monolithic application for its software needs, and it was crumbling due to holiday spikes and other performance issues. Therefore, it has shifted its monolithic application architecture to microservices and achieved following visible advantages.
- 20% increase in conversions
- 98% increase in mobile orders
- Zero downtime during holiday spikes
- 40% saving on computing power
- 25-50% saving on overall costs
Thus, microservices architecture has provided Walmart a competitive edge.
Spotify believes in user experiences, and its monolithic architecture blocks its road to scaling. Therefore, it has a re-built application on microservice platform to sync the development and deployment work going on in its five global development offices among the 600 developers working in two countries.
Moreover, it has formed a full-stake team for each microservice unit consisting of front-end developers, back-end developers, QA team, deployment team, database team, and concerned client-side team with autonomous powers to make required modifications in the system.
Despite some latency and overall management issues, Spotify has experienced some obvious benefits of adapting microservices architecture for its products and applications. For instance,
- It has eased the working on scale based real-world bottlenecks.
- Eased the testing & deployment
- Easy to monitor
- Have version independency
- Less prone to big failures
It has a giant application with a monolithic architecture based on Ruby and Rails framework and technologies. It was working nicely until the operations were limited in the USA. With global expansions, it has stated displaying performance related issues and various symptoms like maintenance challenges.
With the shift to microservices architecture, Groupon has experienced following improvements.
- Fast page load with 50% increase
- Serving the same amount of traffic with the least investment in hardware, etc.
- Fast development with fewer dependencies
- Elimination of redundant features implementation in other countries
Besides these, Groupon has achieved its targeted goals like
- Unification of front-ends
- Give mobiles equal status to web
- Faster site
- Independence to development teams
Microservices and Beyond
Today microservices architecture is a buzz word in software development community and implemented with great zeal in small to large projects. However, microservices architecture is not solutions work ubiquitously in all cases and all contexts.
However, enterprises seldom need the integration of microservices architecture with monolithic architecture to provide hybrid solutions in many instances. Albeit, Monolithic is good for startups and later on, shifting to microservices is the best way to get going in future. If you are not sure where to go and how to define your application architecture, the Perception System is a team of avid software architectures and consultants to provide righteous guidance.
Kindly share here your thoughts and nuances with microservices?