Microservices

Why?

(a.k.a. Common Problems with Monoliths)

• comprehensibility
• language limitations
• modular scalability 
• modularity leaks
• large, loosely-defined teams

What is a microservice?

1 monolith              2+ monoliths

Each monolith can be run and scaled independently, with no shared state

Does micro mean it has to be small?

We're edging around a semantic argument, but micro typically means   concerned with only one thing.

...which may be a huge thing, like payroll. But more typically, they're smaller, like Netflix's streaming API or Amazon's reviews API.

• smaller parts, easier to understand
• specialized languages
• optimized scaling
• strictly defined modules
• small, specialized teams

Advantages

Tradeoffs

• (!) combinatorial complexity
• (!) inflexible module boundaries
• more complex infrastructure and deployment
• cross-team communication very important