What is Akka?
Scalable real-time transaction processing
We believe that writing correct concurrent, fault-tolerant and scalable applications is too hard. Most of the time it's because we are using the wrong tools and the wrong level of abstraction. Akka is here to change that. Using the Actor Model we raise the abstraction level and provide a better platform to build correct, concurrent, and scalable applications. For fault-tolerance we adopt the "Let it crash" model which the telecom industry has used with great success to build applications that self-heal and systems that never stop. Actors also provide the abstraction for transparent distribution and the basis for truly scalable and fault-tolerant applications.
Akka is Open Source and available under the Apache 2 License.
Download from http://typesafe.com/stack/downloads/akka/
Please note that all code samples compile, so if you want direct access to the sources, have a look over at the Akka Docs Project.
Akka implements a unique hybrid
Actors give you:
- Simple and high-level abstractions for concurrency and parallelism.
- Asynchronous, non-blocking and highly performant event-driven programming model.
- Very lightweight event-driven processes (approximately 2.7 million actors per GB RAM).
- Supervisor hierarchies with "let-it-crash" semantics.
- Supervisor hierarchies can span over multiple JVMs to provide truly fault-tolerant systems.
- Excellent for writing highly fault-tolerant systems that self-heal and never stop.
Everything in Akka is designed to work in a distributed environment: all interactions of actors use pure message passing and everything is asynchronous.
For an overview of the remoting see Location Transparency
Messages received by an actor can optionally be persisted and replayed when the actor is started or restarted. This allows actors to recover their state, even after JVM crashes or when being migrated to another node.
Akka can be used in two different ways
- As a library: used by a web app, to be put into WEB-INF/lib or as a regular JAR on your classpath.
- As a microkernel: stand-alone kernel to drop your application into.
See the Use-case and Deployment Scenarios for details.
What happened to Cloudy Akka?
The commercial offering was earlier referred to as Cloudy Akka. This offering consisted of two things:
- Cluster support for Akka
- Monitoring & Management (formerly called Atmos)
Cloudy Akka has been discontinued and the Cluster support is now being moved into the Open Source version of Akka (the upcoming Akka 2.1), while Monitoring & Management (Atmos) has been re-branded as the Typesafe Console, which is now part of the commercial subscription for the Typesafe Stack (see below for details).
Akka is now also part of the Typesafe Stack.
The Typesafe Stack is a modern software platform that makes it easy for developers to build scalable software applications. It combines the Scala programming language, Akka, the Play! web framework and robust developer tools in a simple package that integrates seamlessly with existing Java infrastructure.
The Typesafe Stack is all fully open source.
On top of the Typesafe Stack we also have a commercial product called Typesafe Console which provides the following features:
- Slick Web UI with real-time view into the system
- Management through Dashboard, JMX and REST
- Dapper-style tracing of messages across components and remote nodes
- Real-time statistics
- Very low overhead monitoring agents (should always be on in production)
- Consolidation of statistics and logging information to a single node
- Storage of statistics data for later processing
- Provisioning and rolling upgrades
Read more here.