Talk by Till Rohrmann, Apache Flink Meetup Berlin, 28th January 2015

1. Apache Flink
Akka – Actors for the win
Till Rohrmann
trohrmann@apache.org

2. Problems of the old RPC
service
• Proprietary server/client architecture to
wrap RPCs
• Shortcomings:
– Blocking calls without timeouts
– Poor exception handling
– Error-prone programming abstraction
– Limited scalability
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3. Akka – Actor-based
concurrency
• Framework to write distributed and highly
reactive applications
• Actor-based concurrency inspired by Erlang’s
actor model
• Open source, Apache License 2.0
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4. Actor model
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5. How can Akka help us?
• Nice programming abstraction
• Asynchronous messages with callbacks
• Location transparency of actors
• Fault-tolerant and self-healing
• High throughput and scalability
• Smaller code base to maintain
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6. Akka’s integration with Flink
• Job/TaskManager and JobClient are
actors
• Old RPC are replaced by messages
• Easy to extend functionality by defining
new messages
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JobClient
JobManag
er
TaskManag
er
TaskManag
er
Job

7. Possible improvements
• Make more components an actor to
increase parallelism
– Scheduler/InstanceManager
– ExecutionGraph/Execution
• Make the system more reactive by
asynchronous calls
• Use Akka persistence to recover state of
failed actors
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8. flink.apache.org
github.com/apache/flink
meetup.com/Apache-Flink-
Meetup