Microservices

Microservices 概览

Cost vs benefit

Microservices solve organizational problems
Microservices case technical problems

Problems solved

• Team is too large to work effectively on shared codebase
• Teams are blocked on other teams, can’t make progress
• Communication overhead becomes gigantic
• Product velocity stalled

Problems caused

• Need well-defined business domains for stable APIs
• No more shared DB — distributed transactions?!
• Testing becomes really hard
• Requires dev/ops culture: devs deploy and operate their work
• Job (service) scheduling — manual works for a while…
• Addressibility i.e. service discovery
• Monitoring and instrumentation — tailing logs? Nagios and New Relic? ha!
• Distributed tracing?
• Build pipelines??
• Security???

Why a microservices approach

• Continually evolving applications
• Faster delivery of features and capabilities to respond to customer expectations
• Build and operate a service at scale

Why microservices

• Build and operate a service at scale
• Improved resource utilization to reduce costs
• Fault isolation
• Continuous innovation
• Small focused teams
• Can be written in any language and framework

What is a microservice

• Autonomous service (服务尽量不依赖其他微服务)
  Encapsulates a scenario
  Organized around business capabilities
• Contain code plus state (状态服务化)
  Independently versioned, deployed, and scaled
• Interact with other microservices over well defined interfaces
  Uses protocols such as http
  Have a unique name(URL) tha can be resolved

微服务的目的是为了有效的拆分应用，实现敏捷开发和部署