SAMZA-2579: Force restart feature for Container Placements (#1414)

Changes: The current restart ability for container placements works in the following way:

Tries to fetch resources on a host
Stops the active container if resources are accrued
Tried to start the container on host accrued
In production, we have seen the following observation at Linkedin

Some jobs are configured to use resources for the peak which leads to no headroom left on a host for requesting additional resources
This leads to restart requests failing due to not able to get resources on that host
A fix to this is to implement a force-restart utility , in this version we will stop the container first and then accrue resources. The upside being we will at least free up the resources on the host before issuing resource request, the downside being it will be a best-effort scenario to bring that container back up on that host

API Changes: Added new param values to destinationHost param for container placement request message

LAST_SEEN: Tries to restart a container on last seen host with RESERVE -> STOP -> MOVE policy

FORCE_RESTART_LAST_SEEN: Tries to restart a container on last seen host with STOP -> RESERVE -> MOVE policy
1 file changed
tree: 1cd5140efce60775f7f13e9c591296e24079089a
  1. .gitignore
  2. .reviewboardrc
  3. .travis.yml
  5. KEYS
  10. bin/
  11. bootstrap.gradle
  12. build.gradle
  13. checkstyle/
  14. doap_Samza.rdf
  15. docs/
  17. gradle/
  18. gradlew
  19. gradlew.bat
  20. samza-api/
  21. samza-aws/
  22. samza-azure/
  23. samza-core/
  24. samza-elasticsearch/
  25. samza-hdfs/
  26. samza-kafka/
  27. samza-kv-couchbase/
  28. samza-kv-inmemory/
  29. samza-kv-rocksdb/
  30. samza-kv/
  31. samza-log4j/
  32. samza-log4j2/
  33. samza-rest/
  34. samza-shell/
  35. samza-sql-shell/
  36. samza-sql/
  37. samza-test/
  38. samza-tools/
  39. samza-yarn/
  40. settings.gradle

What is Samza? Build Status

Apache 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.

Samza's key features include:

  • Simple API: Unlike most low-level messaging system APIs, Samza provides a very simple callback-based “process message” API comparable to MapReduce.
  • Managed state: Samza manages snapshotting and restoration of a stream processor's state. When the processor is restarted, Samza restores its state to a consistent snapshot. Samza is built to handle large amounts of state (many gigabytes per partition).
  • Fault tolerance: Whenever a machine in the cluster fails, Samza works with YARN to transparently migrate your tasks to another machine.
  • Durability: Samza uses Kafka to guarantee that messages are processed in the order they were written to a partition, and that no messages are ever lost.
  • Scalability: Samza is partitioned and distributed at every level. Kafka provides ordered, partitioned, replayable, 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 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 from a git checkout, run:

./gradlew clean build

To build Samza from a source release, it is first necessary to download the gradle wrapper script above. This bootstrapping process requires Gradle to be installed on the source machine. Gradle is available through most package managers or directly from its website. To bootstrap the wrapper, run:

gradle -b bootstrap.gradle

After the bootstrap script has completed, the regular gradlew instructions below are available.

Scala and YARN

Samza builds with Scala 2.11 or 2.12 and YARN 2.6.1, by default. Use the -PscalaSuffix switches to change Scala versions. Samza supports building Scala with 2.11 and 2.12.

./gradlew -PscalaSuffix=2.11 clean build

Testing Samza

To run all tests:

./gradlew clean test

To run a single test:

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

To run key-value performance tests:

./gradlew samza-shell:kvPerformanceTest -PconfigPath=file://$PWD/samza-test/src/main/config/perf/

To run yarn integration tests:

./bin/ <dir> yarn-integration-tests

To run standalone integration tests:

./bin/ <dir> standalone-integration-tests

Running checkstyle on the java code

./gradlew checkstyleMain checkstyleTest

Job Management

To run a job (defined in a properties file):

./gradlew samza-shell:runJob -PconfigPath=/path/to/job/

To inspect a job's latest checkpoint:

./gradlew samza-shell:checkpointTool -PconfigPath=/path/to/job/

To modify a job's checkpoint (assumes that the job is not currently running), give it a file with the new offset for each partition, in the format systems.<system>.streams.<topic>.partitions.<partition>=<offset>:

./gradlew samza-shell:checkpointTool -PconfigPath=/path/to/job/ \


To get Eclipse projects, run:

./gradlew eclipse

For IntelliJ, run:

./gradlew idea


To start contributing on Samza please read Rules and Contributor Corner. Notice that Samza git repository does not support git pull request.

Apache Software Foundation

Apache Samza is a top level project of the Apache Software Foundation.

Apache Software Foundation Logo