Thomas Step

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re:Invent: The Journey To Adopt Cloud-Native Architectures For Hyperscale

This is an overview of a session that I went to during re:Invent 2021. I start by providing the notes I took during the session, and then I will give my take and comments if I have any at the end.

Tuesday 14:00

ARC314-R1

Agenda:

• There are certain best practices and architectures when reaching this scale
• Why do you need a journey to adopt cloud-native architecture?
• How to address hyperscale
  • How to improve resilience and scale in monoliths
  • How to leverage domain-driven design for decomposing monoliths to achieve independent scaling of services
• “Hypergrowth happens at the steep part of the growth curve after the initial product or service offerings are defined and before the business matures”
  • Curve looks like an S so hypergrowth would be the steepest gain in revenue (revenue y-axis, time x-axis)
• Key challenges: time to market, scaling limits, inflated blast radius, increased dependencies, and complex deployments
  • Won’t touch on all but two stand out: scale (start with monolith then hit a bottleneck) and inflated blast radius

Journey to adopt cloud-native architectures

• They have published four blogs so far in a series with the name “The Journey To Adopt Cloud-Native Architectures For Hyperscale”
  • go.aws/32cCgCD
• It’s a journey so you need to have a long-term vision/goal
• Focusing on cell-based architecture and domain-driven design (they haven’t published these two concepts yet)

Cell-based Architecture

• Attempt at decentralizing arch
• Instead of a load balancer routing to multiple nodes have a “cell router” that routes to a cell that contains a load balancer with multiple nodes
• A cell should have minimum dependencies (no shared infra)
• A cell is a wholly contained application stack
• An AZ can be considered a cell
• Geo-based cells (AZs and regions) or shuffle sharding
  • Depends on what type of failure you are trying to avoid and what the business requirements are
• “Cell router” can be Route 53 based on geography-based routing
  • For shuffle sharding, you would need to create your own router, but keep in mind that it should be resilient in the same way the cell-based arch is
  • Should have very little logic, only route to shard/cell
  • Needs to be predictable
• Benefits of cell-based:
  • Control of scale
  • Reliable and resilient
  • Easier error detection
  • Contained blast radius
• Tradeoffs for fine-grained or rough-grained cells in terms of cost, complexity, resiliency
• Check out Route 53 Application Recovery Control

Domain-driven, cloud-native architecture

• “Monolith is not a bad design if it meets your needs”
• When are microservices right?
  • When you need to independently scale certain features
  • When multiple teams are collaborating on the same workload
  • When you have different resiliency requirements for different service components
• Microservices challenge:
  • Service boundaries
  • Data consistency and integrity
  • Network congestion and latency
  • Monitoring and managing complexity
  • Build, deploy, and run at scale
  • Decomposing a monolith -> domain-driven design
• DDD (domain-driven design)
  • Focus on end-to-end customer journeys
  • Ubiquitous language understood by domain experts and tech experts
  • Two types of DDD:
    • Strategic DDD ensures arch remains focused on business capabilities
    • Tactical DDD provides design patterns to build microservices
• How to approach this:
  • Identify business domains
  • Use customer journeys (bounded contexts)
    • Don’t create too many microservices (more services means more latency)
  • Prioritize domain
    • Invest first in core domains, see how it goes, then move on
  • Apply tactical DDD
  • Identify microservices iteratively
    • Think about patterns
    • Don’t always create a new microservice
    • Reuse what has already been created
  • Measure outcomes and apply patterns
    • Define success criteria (higher throughput, decreased latency, etc.)
• Example eCommerce company
  • Customer logs in
  • Customer finds a product that fits their budget
  • Product added to cart
  • Select payment method
  • Customer provides shipping information
    • Need to validate
  • Order submitted and sent to back-office for fulfillment
  • Each one of these is a domain event
• In his example, he prioritizes ordering
  • Should ordering be one microservice or multiple?
    • Could be multiple: checkout, shipping address validation, order pricing and taxation, order qualification, order management, order notifications
    • Could have also been a single service
  • Now apply tactical DDD
    • Checkout microservice has a root entity of cart and a value object of item
    • 3 layers: business logic, application, infrastructure
    • Identify data access pattern
• Start small, learn, and iterate: take functionality out of a monolith, put into microservice
  • Sounds like the strangler pattern

My notes:

Once again cell-based architectures came up, so this is a topic to look into and at least make sure would be possible with architectures moving forward.

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