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- Apache Accumulo - Accumulo is a distributed key/value store that provides expressive, cell-level access labels.
- Apache BookKeeper (ZooKeeper subproject) distributed logging service
- Apache CXF DOSGi The Distributed OSGi implementation at Apache CXF uses ZooKeeper for its Discovery functionality. See here for more information: http://cxf.apache.org/dosgi-discovery-demo-page.html
- planning: Apache Flume Service for efficiently collecting, aggregating, and moving large amounts of log data. The next major version is planned to use ZooKeeper: Jira issue
- Apache Hadoop MapReduce The next generation of Hadoop MapReduce (colled "Yarn") uses ZooKeeper. Jira issue, Design paper
- Apache HBase - HBase is the Hadoop database. Its an open-source, distributed, column-oriented store modeled after the Google paper, Bigtable: A Distributed Storage System for Structured Data by Chang et al.
We use ZooKeeper for master election, server lease management, bootstrapping, and coordination between servers. - Apache Hedwig Hedwig is a publish-subscribe system designed to carry large amounts of data across the internet in a guaranteed-delivery fashion from those who produce it (publishers) to those who are interested in it (subscribers).
- Apache Kafka (incubating) Kafka is a distributed publish/subscribe messaging system
- Apache S4 (incubating) S4 is a general-purpose, distributed, scalable, partially fault-tolerant, pluggable platform that allows programmers to easily develop applications for processing continuous unbounded streams of data.
- Apache Solr - In the "Cloud" edition (v1v4.5x and up) of enterprise search engine Apache Solr, ZooKeeper is used for configuration, leader election and more.
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