Session presented at the 6th IndicThreads.com Conference on Java held in Pune, India on 2-3 Dec. 2011. http://Java.IndicThreads.com --- Historically writing correct concurrent, scalable and fault-tolerant applications has been very hard. Akka is an attempt to simplify writing concurrent, scalable and highly available software for the JVM. Akka has an API both for Scala and Java. Akka uses the Actor Model together with Software Transactional Memory (STM) to raise the abstraction level. For fault-tolerance it adopts the “Let it crash” model which help in building self healing always on systems. The presentation walks through the Akka features for building a web scale system. We would look at a real world case study in which Inphina developed a web scale framework using Akka which is capable of processing 150 million streaming messages a day. We would discuss the architecture and key design decisions. http://www.indicthreads.com/9241/scalable-applications-with-akka/

1. Building Massively Scalable
Applications with Akka
Vikas Hazrati
Inphina Technologies
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2. what?
Platform for next generation, event driven,
scalable and fault tolerant architectures on the
JVM.
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3. akka
A actor-based concurrency framework
Provides solutions for non blocking concurrency
Written in Scala, also works in Java
Open source
Now at 1.3-RC2 (to be released this weekend)
Lead developer and founder: Jonas Boner
JRockit, AspectWerkz, AspectJ, Terracotta
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4. issues
concurrency
scalability
fault tolerance
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5. why akka
simpler concurrency
event driven
scale up or scale out
fault tolerance
remoting
scala and java api
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6. aha actors!
message-Passing Concurrency
share NOTHING
isolated lightweight processes
communicates through messages
asynchronous and non-blocking
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7. actors
defined in the 1973 paper by Carl Hewitt
popularized by Erlang
alleviates the dev
from explicit locking
and thread management
easy to write concurrent and parallel systems
actors like objects BUT dont share state
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8. actor models
Thread-based
Event-based
• Very lightweight
• can easily create millions on a single
workstation
(6.5 million on 4 G RAM)
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9. 9

10. defining an actor
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11. firing messages
bang bang bang
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12. send anything
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13. fault tolerance
let it crash
linked set of actors
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14. all for one
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15. one for one
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16. supervisor hierarchies
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17. fault management
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18. other concepts
Akka STM
Remote Actors
Akka Serialization
Persistence
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19. problem statement
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20. considerations
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21. hmm...
STM – X
Serialization – X
Persistence – X
Remoting – ?/X
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25. issues
maxing out on the os threads
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26. dispatchers
thread based – dedicated os thread
bound
event based – backed by pool of
threads
priority event based
work stealing
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27. 27

28. ala carte'
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29. used in ...
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30. more information
http://akka.io/docs/akka/1.3-RC1/intro
http://thoughts.inphina.com/tag/akka/
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31. Everyone ! “Thanks”
vhazrati@inphina.com
@vhazrati
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