Microservices represent an architectural approach to software development that structures an application as a collection of modular, self-contained services rather than a single, monolithic unit. This approach provides greater agility, scalability, and resilience.
As companies increasingly look to build and deploy complex, large-scale applications in the cloud, many are turning to microservices architecture for its flexibility and decentralized nature. However, transitioning to microservices also introduces new complexities around managing and coordinating large numbers of independent component services.
This comprehensive guide examines the benefits and challenges of microservices, key enabling technologies, and how to successfully implement a microservices approach. It offers valuable guidance both for engineering teams looking to rearchitect monolithic legacy applications as well as product companies evaluating offshore software developers to build new microservices-based solutions.
What Are Microservices?
Microservices refer to an architectural style that structures an application as a collection of loosely coupled, independently deployable services rather than build the entire app as one monolithic unit.
“The microservice architectural style is an approach to developing a single application as a suite of small services, each running in its own process and communicating with lightweight mechanisms, often an HTTP resource API.” – Martin Fowler
In this decentralized model, services have a focused functionality and can interact with other services and be deployed independently through clearly defined interfaces, typically RESTful APIs or similar messaging protocols. This allows for more rapid, frequent updates since a change to one component doesn’t impact the entire system.
Some examples of common microservices for an e-commerce application include:
- Product Catalog Service – Browse and search products
- Shopping Cart Service – Add/remove products and manage cart
- Order Service – Place orders and process payments
- User Account Service – Manage user data and authentication
Each service handles its own logic and data storage while the application coordinates requests across services. So in essence, a microservices architecture decomposes large monolithic apps into a distributed suite of modular components.
This provides greater flexibility to scale or update specific areas of an application on demand. Amazon and Netflix are well-known examples of companies using microservices.
| Monolithic App | Microservices App |
|---|---|
| Single unified unit | Collection of independent services |
| Code, data, config combined | Modular components with own logic/data |
| Entire app scaled together | Each service scales independently |
| waterfall dev model | Enables agile parallel teams |
So in summary, microservices provide greater agility, scalability and velocity versus traditional monolithic architectures by decomposing apps into distributed, decoupled services. However, this distributed design also introduces complexities around coordinating and deploying large numbers of services.
Key Benefits of Microservices
Microservices architecture offers several notable benefits over monolithic app design:
Faster Time to Market
With decentralized teams and smaller, focused services, development can progress in parallel. New features or upgrades can be deployed for specific services without rebuilding or testing the entire application. This agility supports continuous delivery and faster time to market with incremental enhancements.
Easier Maintenance & Updates
Microservices are loosely coupled, so most updates only impact a single service rather than force an entire monolithic app deployment. This simplifies testing and allows developers to innovate and respond to changing business requirements faster.
Flexible Scaling
The modular design allows individual services to scale up quickly to meet demand spikes rather than scale the entire application. So capacity can be matched precisely to usage needs in a cost-efficient way.
Fault Isolation & Resilience
Issues with a single service won’t necessarily bring down other unaffected services or the whole app. This improves overall uptime and resilience. Microservices also lend themselves well to continuous integration and infrastructure automation.
Technology Flexibility
Teams can use the coding language or frameworks best suited for a service’s needs rather than forced into a uniform technology platform. The ability to mix and recombine languages and frameworks prevents vendor or technology lock-in.
Challenges with Microservices
While microservices offer benefits in velocity, scaling, and resilience, the distributed design also introduces complexities:
Increased Deployment Overhead
There are more services to coordinate deployments across different servers or containers. Automation and orchestration become critical to manage thousands of services.
Debugging & Monitoring
Debugging gets more complicated with numerous services rather than a monolith. Centralized monitoring, metrics, and logging are crucial for observability across a microservices ecosystem.
Added Network Complexity
The architecture depends on reliable service networking and communication patterns. Introducing many services with heavy inter-communication can create latency issues.
Data Replication Overhead
Each service may need its own database or other replicated data components, meaning increased storage and memory demands. Caching layers help minimize this issue by reducing duplicate data requests.
Talent Scarcity
There are fewer developers experienced with building decoupled, resilient services oriented around business capabilities versus monolithic models. DevOps skills and automation proficiency also grow in importance with microservices teams.
In essence, a microservices approach trades simplicity for agility. Done right, microservices can accelerate feature velocity, scale optimally, and prevent outages from rippling systemwide. However, complexity climbs dramatically with added services. Operations overhead around deployment, networking, monitoring, data flows, and team skills should factor prominently into execution roadmaps.
Let’s look at some of the key technologies that help enable microservices…
Technologies Enabling Microservices
Several capabilities help facilitate loosely coupled services-based architectures:
Containers & Container Orchestration
Containers package an application’s code with just the supporting components like libraries and dependencies required for it to run evenly across different computing environments. This provides greater consistency versus discrepancies across developer laptops, test environments, staging, and production.
Popular container platforms Docker container allow developers to build, share and run containers without worrying about environment inconsistencies.
Container orchestration helps automate deploying, networking, scaling and availability of containerized microservices across clusters of servers. Kubernetes has become an open standard orchestrator, natively managing containerized workloads and services across public and private cloud infrastructure.
Paired together, containers and orchestrators like Kubernetes simplify deploying large numbers of microservices across dynamic, elastic runtimes.
Service Mesh
A service mesh further manages communications control and observability across microservices, handling:
- Service discovery
- Resilient networking between containers
- Traffic management
- API gateways
- Security policies
- Metrics collection
Popular open-source service mesh solutions include Istio and Linkerd which integrate natively with Kubernetes. By externalizing duties like service routing, telemetry, and policy out of the code, teams can develop microservices faster without needing to reinvent foundational mechanisms.
API Gateways
An API gateway provides a unified entry point for clients and acts as a reverse proxy to abstract away service complexities. It can handle security, rate limiting, monitoring, metrics, and routing requests to appropriate microservices downstream.
Leading API gateway products include Kong, Tyk and Apigee. Used in conjunction with service meshes, API gateways and meshes complement each other in handling external and internal service networking respectively.
Messaging/Event Streaming
Asynchronous messaging helps connect services and data flows through lightweight event streaming:
- Message queues reliably route information between services
- Event streaming propagates state changes externally through systems
- Function-as-a-Service executes real-time code in response to events
Widely used open source message brokers include Apache Kafka, RabbitMQ and Apache Pulsar. Paired with service meshes and API gateways, messaging enables responsive, decoupled microservices.
How to Successfully Adopt Microservices
Migrating legacy monoliths or designing new microservices-based systems involves careful planning and execution across technology, process, and organization.
Get Leadership Buy-In
Transitioning from monoliths requires executive commitment on par with a major technology replatforming. Ensure stakeholders understand the long-term vision, execution roadmap, and change impacts on people, processes, governance, and technology.
Take an Incremental Approach
Rather than an immediate rewrite, incrementally port over targeted services from monoliths first. Build APIs around existing functions to segment out newer microservices; retire retired capabilities later. This minimizes risk while validating design patterns.
Implement Centralized Observability
Unified monitoring, logging, and metrics are mandatory when dealing with thousands of distributed services versus a monolith. Platforms like Prometheus, Grafana, Elasticsearch, Zipkin, Jaeger or commercial tools provide insight across services.
Standardize Foundational Building Blocks
Define standards around security, data access, messaging protocols, APIs, networking, runtimes, and testing to streamline development. Container platforms and service meshes handle foundational infrastructure.
Automate Testing & Deployments
Automated testing, infrastructure provisioning and continuous deployment minimize complexity dealing with so many decoupled components. Pipeline frameworks like Jenkins, Spinnaker, and CircleCI emphasize code quality and predictable release processes.
Instill a DevOps Culture
The increased pace of code releases and infrastructure demands drive the need for collaboration between development and operations teams. Shared goals, tools, practices, and responsibilities break down silos.
Govern Architecture Decentralization
While architects relinquish some control over system specifics, increased governance ensures services align to standards and patterns. Policy changes cascade quickly within decentralized systems.
Rightsize Services Granularity
Avoid either too large or too small service boundaries. Target a level decomposing by business capabilities or domains versus technical functions or app tiers. Services require clear separation of duties and data ownership.
Key Takeaways & Summary Tips
- Microservices architecture breaks down monolithic apps into distributed, decoupled services around capabilities.
- Benefits include agility, flexible scaling, fault isolation, and technology heterogeneity.
- Drawbacks encompass added complexity around networking, testing, monitoring, and deployments.
- Containers, container orchestrators and service meshes help manage microservices environments.
- Take an incremental approach focused on automation, APIs, governance and culture change.
In closing, microservices empower product velocity, scaling, and resilience via modular services versus monolithic apps. But distributed coordination demands greater operations tooling, monitoring, and automation.
Organizations must balance the benefits versus the added complexities – factoring deeply both the technical and process transformations required to successfully execute this architectural approach at scale.
Frequently Asked Questions
What are some examples of companies using microservices?
Some well-known examples of consumer web companies leveraging microservices include Netflix, Amazon, eBay, Twitter, PayPal, Uber and Airbnb. Financial services firms like Capital One, JP Morgan Chase and Goldman Sachs also actively use microservices in their software application stacks.
How small should a microservice be?
There are no definitive rules, but granularity principles suggest targeting the service boundaries around specific business capabilities or contexts versus technical functions or application tiers. Avoid either overly large or fine-grained services preferable.
How do microservices communicate?
Typical communication patterns between services involve either synchronous RESTful HTTP/JSON APIs or asynchronous messaging protocols like AMQP or Kafka. Avoid unnecessary direct coupling between services.
Can you deploy microservices without containers?
It’s possible but not optimal. Containers create deployment portability for services across environments and infrastructure. Orchestrators like Kubernetes help automate container deployment, networking, scaling and availability.
What coding languages best suit microservices?
Teams have flexibility across services, with no need to enforce uniform languages or technology stacks. Java, JavaScript/Node.js, C#/.NET, Go, Python, PHP and Ruby all work well for microservices implementations.
How is microservices different than SOA?
Service-oriented architecture (SOA) is an older architectural style that also builds applications from shared, reusable components. However, SOA focuses more on enterprise application integration rather than core architectural decomposition like microservices.
Last modified: February 7, 2024