The WAGED rebalancer returns the previously calculated assignment on calculation failure (#514)

* The WAGED rebalancer returns the previously calculated assignment on calculation failure.

This is to protect the cluster assignment on a rebalancing algorithm failure. For example, the cluster is out of capacity. In this case, the rebalancer will keep using the previously calculated mapping.
Also, refine the new metric interface, and add the RebalanceFailureCount metric for recording the failures.

Modify the test cases so that DBs from different test cases have a different name. This is to avoid previous test records to be returned by the rebalancer on calculation error.
14 files changed
tree: 5d1e2ef70570518b22722804b14899c4a76c8c5f
  1. helix-admin-webapp/
  2. helix-agent/
  3. helix-core/
  4. helix-front/
  5. helix-rest/
  6. recipes/
  7. scripts/
  8. website/
  9. .gitignore
  10. build
  11. bump-up.command
  12. deploySite.sh
  13. helix-style-intellij.xml
  14. helix-style.xml
  15. hpost-review.sh
  16. LICENSE
  17. NOTICE
  18. pom.xml
  19. README.md
README.md

Apache Helix

Helix is part of the Apache Software Foundation.

Project page: http://helix.apache.org/

Mailing list: http://helix.apache.org/mail-lists.html

Build

mvn clean install package -DskipTests

WHAT IS HELIX

Helix is a generic cluster management framework used for automatic management of partitioned, replicated and distributed resources hosted on a cluster of nodes. Helix provides the following features:

  1. Automatic assignment of resource/partition to nodes
  2. Node failure detection and recovery
  3. Dynamic addition of Resources
  4. Dynamic addition of nodes to the cluster
  5. Pluggable distributed state machine to manage the state of a resource via state transitions
  6. Automatic load balancing and throttling of transitions