Learning Notes 'System Architecture Foundations'

May 05, 2022 . Lecture Notes, System Design
Infomration Value
Course Link LinkedIn Learning: System Architecture Foundations
Learning Date 2022-05-05
Why Taking this course? Wanna learn systematic way of designing complex software system.
Summary I learned the design process of complex system, along with 5 common architecture patterns

Architect

  • Everything starting from customers and centered on communication, rather than starting form techniques.
    • Agile architect:
      • How to break the chicken-egg problem between “user requirement” and “software development result”: use “inspect and adapt loop” (i.e. building MVP and get early feedbacks). More specifically, the 4-step cycles consisting of:
      • Develop –> review –> talk to user –> refine –> (repeat this cycle)
      • Cycle around 2 days.
    • Everyone is architect (no need permission as architect).
      • Agile architect job is : teaching, coaching, coordinating
      • Agile architect job is: keep the big thing in the head rather than low-level code. Developer know the code best.
    • From developer to architect:
      • Good at programming
      • At least read code (open source projects)

Thinking Architecturally:

  • Conway’s law:
    • Agile development: require both system architecture and development style to be agile
      • System architecture: microservice (very thin and tall piece from frontend to backend that one developer handle)
      • Development style: quick experiment and quick feedbacks.
  • Agile: Incremental development (one piece at a time), instead of big up-front design. (BUFD). Agile development will postpone the technical decision but more emphasize user requirements.

Design Process

  • Start with “Problem Statement” describe the problem and solution if the computer doesn’t exist. Describe the problem in the form of a set of “user stories” (each user story is a requirement of small piece)
  • Narrowing w/ slice and dice (draw a high-level picture with many if-condition, and each path is a narrow’s scope)

Category of Architecture

  • System architecture
  • Enterprise architecture (it’s a failed approach due to complex): structure of business structure/process itself; structure of code should reflect business process

Architecture Pattern

  • Pattern 1: Monolith
    • What is “monolith”: an all-in-one system that contain complex components in a single system.
    • Pro: (almost no)
    • Cons: very hard to maintain
    • Type 1: N-tiers (one types of monolith containing
      • UI
      • Business Logic
      • Database
    • Type 2: Vertical divisions (very narrow-scope service where each include independent database and UI).
  • Pattern 2: Microkernel Pattern
    • How:
      • Core service handle core logic.
      • Other auxiliary service are plug-ins to these services.
    • Application: This types of architecture not only for operation system, but also can be used for business application.
    • Pro: isolation between core kernels avoid big ball of mud dependencies. Also, the plugins are usually small and easy to write.
    • Cons: APIs to the kernel are delicate.
  • Pattern 3: Message-based architecture.
    • Example 1: Job run independently and communicate via message (a small piece of encapsule information) on message bus.
    • Each job can either talk to each other directly, or via a intermediate bloker.
    • Example 2: Pub/sub system: rather than using queue, receiver agent subscribe to a broker.
  • Pattern 4: Microservice
    • Large service is made up of many small independent services.
    • requirement:
      • Small (100 line of codes)
      • Independently deployable (most important)
      • Fully autonomous (own database)
      • Hide implementation details
      • Almost always distributed.
  • Pattern 5: Reactive pattern.