As enterprise development teams increase the time they spend using cloud computing, many are challenged by a move from a scale-up (monolithic) to a scale-out (distributed) architecture. Reactive system development and microservices are two evolving answers that architects are embracing, but making them work well at scale calls for a departure from the traditional approach of object-oriented programming models and defensive programming through try-catch, which is now being replaced by a highly-resilient supervision model and a "let it crash" philosophy. In this webinar for Architects, guest speaker Jeffrey Hammond, Forrester Vice-President and Principal Analyst joins Jonas Bonér, CTO/Co-founder of Lightbend and creator of Akka, the actor-based, message-driven runtime for the JVM, to discuss one emerging programming pattern that’s gaining popularity with teams developing for the cloud––the Actor model. They will discuss some history, why the Actor model is a better fit for large, scale-out systems and microservices delivery, the types of workloads using it today, and how to implement an Actor-based system in your existing Java environment.

2. The Benefits Of The Actor Model: A
Pragmatic Overview For Architects
Jeffrey Hammond, Vice President & Principal Analyst
Jonas Bonér, CTO & Co-founder at Lightbend, Inc.
Sept 15, 2016

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US Tech Market Outlook For 2016 And 2017: Cloud And Business Caution Will Slow Growth
Cloud adoption reaches a tipping point

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Strategies for moving to the cloud
1. Lift-and-shift: re-host existing systems with little or no
modification.
2. Lift-and-extend: re-host system but add substantial
modifications to take advantage of cloud platforms
and/or services.
3. SaaS substitution: replace a core system with a new
SaaS product
4. Full replacement: replace a system with one or more
custom services built in the cloud.
5. Hybrid extension: leave a system and its data in
place, add new modules and/or data in the cloud.

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What a modern application looks like

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Source: How To Capture The Benefits Of Microservice Design
Microservices aid modern applications

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Source: Microservices Have An Important Role In The Future Of Solution Architecture
Microservices can extend workloads

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Source: Microservices Have An Important Role In The Future Of Solution Architecture
Microservices vs. traditional applications

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DIY microservices are challenging
› Microservices create a dependency-
management challenge
› Continuous integration and delivery is difficult to
scale
› Microservice composition requires robust API
and messaging technologies
› Internet-scale applications on public cloud
platforms require new programming patterns and
platforms

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How are developers moving forward?
1. Adapting today's programming models and
platforms to microservice designs.
2. Adopting new programming models on today's
platforms.
3. Adopting new programming models and new
microservice platforms.

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Microservice platforms are emerging
Source: Microservices Have An Important Role In The Future Of Solution Architecture

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Remember 1973?

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Source: Carl Hewitt, Peter Bishop, and Richard Steiger, "IJCAI'73 Proceedings of the 3rd international joint conference
on Artificial intelligence," ACM Digital Library, August 20, 1973
The Actor Model – All the way from 1973
The Actor Model envisioned
"the prospect of highly parallel computing
machines consisting of dozens, hundreds, or even
thousands of independent microprocessors, each
with its own local memory and communications
processor, communicating via a high-performance
communications network."

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Erlang took Actors into the real world

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Source: http://www.brianstorti.com/the-actor-model/
How the Actor Model works
Actors can:
1. Create more actors;
2. Send messages to
other actors;
3. Designate what to do
with the next
message. (i.e.
manipulate internal
state)
Mailbox
Mailbox
Mailbox
Internal
State

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The Actor Model and Microservices
Actors:
› Make complex parallel processing tasks simpler
› Provide building blocks for resiliency
› Ease updates of individual actors
› Present a migration path for apps with granular
entity models

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The challenge w/ Actors in Erlang
HTML/CSS, 12.4%
Java, 10.9%
C++, 9.8%
JavaScript,
9.2%
C#, 7.9%
PL/SQL,
6.7%
PHP,
5.1%
C, 4.8%
VB.NET, 4.1%
Basic/VB, 3.5%
COBOL, 2.9%
Python, 2.6%
ABAP, 2.4%
Delphi/ObjPascal,
1.9%
Perl, 1.6%
Obj-C, 1.5%
MATLAB,
1.4%
Swift, 1.3%
Ruby, 1.3% CICS, 1.3% RPG, 1.2%
Groovy, 0.9%
Source: Forrsights Developer Survey, Q2 2016 n=1815 developers
How do you allocate the time you spend writing code across the following programming languages?

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Actor Model frameworks meet popular
VMs
› JVM – Akka, Quasar
› .NET - Akka.NET, Orleans, Service Fabric
› C++ - CAF

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More about Akka
› Implementation of the Actor Model on the JVM (Java &
Scala APIs)
› Inspired by the Erlang model for Resilience
• Not part of the original Actor Model
• Supervision: Parent monitors the life-cycle of the children
• Akka Cluster ensures unified semantics across nodes as in a local
context
› Runtime w/ lots of add-on modules:
• Remote & Cluster
• HTTP & IO
• Streams & Integration
• Persistence & FSM

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Lagom build on Akka’s Actor Model
› High-productivity framework for Microservices
› Opinionated:
• Asynchronous by default
• REST, Streaming and Pub/Sub messaging
• WebSockets or HTTP
• Event Sourcing/CQRS for persistence
• Dev Console with hot code reload etc.
• Seamless deploy to production

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Example of the Actor Model in action
› IOT: Nest (smart home), Samsung (wearable health),
eero (consumer WiFi), Mesh Systems, Quorum (Oil &
Gas Service)
› Streaming: iHeart Radio (music), Major League
Baseball, HBO (video)
› Personalization: William Hill (gambling), Gilt Group
(retail)
› Financial Services: Capital One (auto loans), UniCredit
(retail banking)
› Technology: Kafka, Flink, Gearpump (streaming data),
Riak (distributed database)

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Closing thoughts
• Moving to the cloud demands a new
architectural approach
• Microservices mesh well with public cloud
concepts
• Microservices /= Containers
• Microservice frameworks abstract developers
from lower level plumbing
• Options exists for mainstream programming
languages and virtual machines like Java and
.NET

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Resources
Forrester: How To Capture The Benefits Of
Microservices Design
http://reprints.forrester.com/#/assets/2/311/'RES13
4866'/reports
Lightbend: Reactive Microservices Architecture
http://lightbend.com/reactive-microservices-
architecture