baeeq / incubator-samza

Mirror of Apache Samza

What is Samza?

Apache Incubator Samza is a distributed stream processing framework. It uses Apache Kafka for messaging, and Apache Hadoop YARN to provide fault tolerance, processor isolation, security, and resource management.

• Simpe API: Unlike most low-level messaging system APIs, Samza provides a very simple call-back based "process message" API that should be familiar to anyone that's used Map/Reduce.
• Managed state: Samza manages snapshotting and restoration of a stream processor's state. Samza will restore a stream processor's state to a snapshot consistent with the processor's last read messages when the processor is restarted.
• Fault tolerance: Samza will work with YARN to restart your stream processor if there is a machine or processor failure.
• Durability: Samza uses Kafka to guarantee that messages will be processed in the order they were written to a partition, and that no messages will ever be lost.
• Scalability: Samza is partitioned and distributed at every level. Kafka provides ordered, partitioned, re-playable, fault-tolerant streams. YARN provides a distributed environment for Samza containers to run in.
• Pluggable: Though Samza works out of the box with Kafka and YARN, Samza provides a pluggable API that lets you run Samza with other messaging systems and execution environments.
• Processor isolation: Samza works with Apache YARN, which supports processor security through Hadoop's security model, and resource isolation through Linux CGroups.

Check out Hello Samza to try Samza. Read the Background page to learn more about Samza.

Building Samza

To build Samza, run:

./gradlew clean build

Scala and YARN

Samza builds with Scala 2.9.2 and YARN 2.0.5-alpha, by default. Use the -PscalaVersion and -PyarnVersion switches to change versions. Samza supports building Scala with 2.8.1 or 2.9.2, and building YARN with 2.0.3-alpha, 2.0.4-alpha, and 2.0.5-alpha.

./gradlew -PscalaVersion=2.8.1 -PyarnVersion=2.0.3-alpha clean build

YARN protocols are backwards incompatible, so you must pick the version that matches your YARN grid.

Testing Samza

To run all tests:

./gradlew clean test

To run a single test:

./gradlew clean :samza-test:test -Dtest.single=TestStatefulTask

Maven

Samza uses Kafka, which is not managed by Maven. To use Kafka as though it were a Maven artifact, Samza installs Kafka into a local repository using the mvn install command. You must have Maven installed to build Samza.

Developers

To get eclipse projects, run:

./gradlew eclipse

For IntelliJ, run:

./gradlew idea

Pardon our Dust

Apache Samza is currently undergoing incubation at the Apache Software Foundation.