Monolith vs microservices comparison - Quick Revision & Key Differences

Recall & Review

beginner

What is a monolithic architecture?

A monolithic architecture is a single unified software application where all components are tightly connected and run as one process.

beginner

What defines a microservices architecture?

Microservices architecture breaks an application into small, independent services that communicate over a network, each handling a specific business function.

intermediate

What is a key advantage of microservices over monoliths?

Microservices allow independent development, deployment, and scaling of services, making the system more flexible and easier to maintain.

intermediate

What is a common challenge when using microservices?

Managing communication between services, handling data consistency, and increased operational complexity are common challenges in microservices.

beginner

When might a monolithic architecture be preferred?

Monoliths are often preferred for simple applications or when quick development and deployment are needed without complex infrastructure.

Which architecture runs all components as a single process?

A Monolithic

B Microservices

C Serverless

D Event-driven

Monolithic architecture runs all components together in one process.

What is a main benefit of microservices?

A Independent scaling of services

B Tight coupling of components

C Simpler deployment as one unit

D Less network communication

Microservices allow each service to scale independently.

Which is a challenge unique to microservices?

A Limited scalability

B Single codebase management

C Complex inter-service communication

D Monolithic deployment

Microservices require managing communication between many independent services.

When is a monolithic architecture usually better?

A For very large, complex systems

B When quick, simple development is needed

C When independent service scaling is critical

D For distributed teams working separately

Monoliths are simpler and faster to develop for small or simple projects.

Microservices communicate mainly through:

A Single database access

B Direct function calls

C Shared memory

D Network calls (APIs)

Microservices communicate over the network using APIs or messaging.

Explain the main differences between monolithic and microservices architectures.

Think about how the app is built and managed.

Describe scenarios where you would choose monolith over microservices and vice versa.

Consider project size and team structure.

Practice

1. Which of the following best describes a monolithic architecture?

easy

A. Many small independent services communicating over a network

B. A database optimized for distributed transactions

C. A cloud service that automatically scales resources

D. A single large application where all components are tightly integrated

Solution

1. Step 1: Understand monolithic architecture

   A monolithic architecture means all parts of the application are combined into one single unit.

2. Step 2: Compare with other options

   Many small independent services communicating over a network describes microservices, C cloud scaling, and D databases, not monoliths.

3. Final Answer:

   A single large application where all components are tightly integrated -> Option D

4. Quick Check:

   Monolith = single big app [OK]

Hint: Monolith = one big app, microservices = many small apps [OK]

Common Mistakes:

• Confusing microservices with monolith
• Thinking monolith means cloud scaling
• Mixing database types with architecture

2. Which syntax correctly describes a microservice in a system design diagram?

easy

A. Multiple boxes each labeled with a specific service name

B. A single box labeled 'App' containing all modules

C. A database icon connected to a single app box

D. A cloud icon with no internal components

Solution

1. Step 1: Identify microservice representation

   Microservices are shown as multiple small boxes, each representing a service.

2. Step 2: Eliminate incorrect options

   A single box labeled 'App' containing all modules shows a monolith, C shows database relation, D is too vague.

3. Final Answer:

   Multiple boxes each labeled with a specific service name -> Option A

4. Quick Check:

   Microservices = many small boxes [OK]

Hint: Microservices = many small boxes, monolith = one big box [OK]

Common Mistakes:

• Choosing single box for microservices
• Confusing database icons with services
• Ignoring service labels

3. Given a system with a monolithic app and a microservices app, which scenario shows better scaling for microservices?

medium

A. Scaling the entire monolith when only one feature needs more resources

B. Scaling only the specific microservice that handles the busy feature

C. Scaling the database only in the monolith

D. Scaling the user interface layer in the monolith

Solution

1. Step 1: Understand scaling in monolith vs microservices

   Monolith requires scaling the whole app, microservices allow scaling individual services.

2. Step 2: Identify the efficient scaling method

   Scaling only the busy microservice is more efficient and flexible than scaling the entire monolith.

3. Final Answer:

   Scaling only the specific microservice that handles the busy feature -> Option B

4. Quick Check:

   Microservices scale individual parts [OK]

Hint: Microservices scale parts; monolith scales whole app [OK]

Common Mistakes:

• Thinking monolith scales parts independently
• Confusing database scaling with app scaling
• Ignoring microservice granularity

4. A team tries to split a monolithic app into microservices but faces frequent communication failures. What is the most likely cause?

medium

A. They deployed all microservices on the same server

B. They used a single database for all microservices

C. They did not implement proper API contracts between services

D. They kept all code in one repository

Solution

1. Step 1: Identify communication needs in microservices

   Microservices communicate over APIs; clear contracts are essential to avoid failures.

2. Step 2: Analyze other options

   Using a single database or same server is possible but less likely to cause communication failures; code repo does not affect runtime communication.

3. Final Answer:

   They did not implement proper API contracts between services -> Option C

4. Quick Check:

   API contracts prevent communication failures [OK]

Hint: API contracts are key for microservice communication [OK]

Common Mistakes:

• Blaming database sharing for communication errors
• Assuming deployment location causes failures
• Confusing code repo structure with runtime issues

5. A startup plans to build a new product with a small team and expects rapid changes. Which architecture is best and why?

hard

A. Monolith, because it is simpler to develop and deploy quickly

B. Microservices, because it allows independent scaling from day one

C. Monolith, because it supports multiple databases easily

D. Microservices, because it requires fewer resources initially

Solution

1. Step 1: Consider team size and speed needs

   A small team with rapid changes benefits from simpler, faster development and deployment.

2. Step 2: Evaluate architecture fit

   Monolith is simpler to build and deploy quickly; microservices add complexity and overhead not ideal for small teams initially.

3. Final Answer:

   Monolith, because it is simpler to develop and deploy quickly -> Option A

4. Quick Check:

   Small team + fast changes = monolith [OK]

Hint: Small teams start monolith for speed, microservices add complexity [OK]

Common Mistakes:

• Choosing microservices for small teams without need
• Assuming microservices always scale better initially
• Ignoring development speed and team skills