We change a monolithic system only when we have no other choice. Traditional enterprise systems are tightly-coupled; all-in-one, all-or-nothing, difficult to scale, difficult to understand and difficult to maintain. Rather than swiftly capture opportunity, we ponder if it’s really worth it—is it worth upsetting the delicate balance of the house of cards we call our enterprise system? Often the opportunity quickly disappears, captured by a faster company. Some people have started calling this “Getting Ubered”. So what can you do about it? Talking about Microservices is one thing, but how can your organization start taking action to address this issue? In this webinar by battle-hardened Enterprise Advocate, Kevin Webber, we walk through the 6 key concepts to understand as a guide for taking action: 1. Domain Driven Design (DDD) 2. Asynchronous messaging 3. API management 4. Dependency management 5. CQRS & event sourcing 6. Transactions & ordering Reactive Platform has what you need to breath new life into your legacy system with a new Microservices-based approach.

1. The 6 Rules for Modernizing Your Legacy
Java Monolith with Microservices
by Kevin Webber (@kvnwbbr)

2. ALegacyMonolith Story

13. heritage
architecture
» Single points of failure
» Impossible to scale out
(shared mutable state, etc)
» Different non-functional
requirements (reads,
writes, compute)
» Optimized for none!
» Long, risky release cycles

14. Howdo Microservices
help?

25. Microservices
» Ubiquitous language
» Well defined models &
boundaries
» Single responsibility
» Independently deployable,
scalable, resilient
» Communicate via async
messaging
» Own their data
» Don't expose a public API

26. Approach?
Principles
» responsive, resilient,
elastic, message-driven

27. Approach?
Principles
» responsive, resilient,
elastic, message-driven
Concepts
» bounded contexts (DDD),
event sourcing, CQRS, CAP
(eventual consistency)

28. Approach?
Principles
» responsive, resilient,
elastic, message-driven
Concepts
» bounded contexts (DDD),
event sourcing, CQRS, CAP
(eventual consistency)
Tools
» Typesafe Reactive Platform
(Play, Akka, Spark)

29. Conceptsand patterns
We will cover:
» Domain Driven Design (DDD)
» Async messaging
» API management
» Dependency management
» CQRS & event sourcing
» Transactions & ordering

30. Domain Driven Design

36. Getting started
» Model sub-domain at package
level
» Tip: Visualize existing
architecture with a tool
like Structure101
» Define public RESTful API
at package level (use async
messaging inside package at
service level)
» Refactor for physical
separation, remove package

37. Goingasync

42. Async Benefits
» Not wasting resources
» Memory, CPU, threads
» Embracing failure
» Not expecting a return
from a remote service
» Designing for all
scenarios

43. API management

55. API mgmt.
» Messaging patterns
» Pub/sub, point-to-point,
streaming
» API gateway
» Routing, aggregation,
protocol translation
» Discovery
» Service discovery,
registry, versioning

56. Dependencymanagement

63. CQRS & eventsourcing

72. Transactionsand
ordering

73. Considerations
» ACID doesn't work across location/trust boundaries
» No 2-Phase commits (2PC)
» No holding locks for the duration of work
» In distributed systems we need to compensate for
for failure rather than prevent failure

76. Whatnext?

82. Microservices
with Lightbend
» Play for API gateway
» Akka for core microservices
(DDD, CQRS, event sourcing)
» ConductR for cluster
management (service
registry, discovery,
architecture visualization,
security)

83. Lagom
Monolithto microservices
» Webinar: March 17, 1PM PST / 4PM EST
» https://www.lightbend.com/discover-lagom
» Ready-to-use connectors: event-sourcing, CQRS
» Launch all microservices with a single command
» Instantly visible code updates

84. Thankyou!
Visit https://www.lightbend.com/products/lightbend-
reactive-platform to get started
Contactinfo
» Twitter: @kvnwbbr
» Email: kevin.webber@lightbend.com

85. LIGHTBEND REACTIVE PLATFORM
Full Lifecycle Support for Play, Akka, Scala and Spark
Give your project a boost with Reactive Platform:
• System orchestration for resilient releases
• Real-time monitoring of asynchronous systems
• Self-healing for network partitions, node and apps
• Availability protected with configurable user quotas
• Certified, load-tested Reactive Runtime
Enjoy learning? See about the availability of
on-site training for Scala, Akka, Play and Spark!
GET STARTED