Elassandra

Elassandra is a fork of Elasticsearch modified to run on top of Apache Cassandra in a scalable and resilient peer-to-peer architecture. Elasticsearch code is embedded in Cassanda nodes providing advanced search features on Cassandra tables and Cassandra serve as an Elasticsearch data and configuration store.

Elassandra supports Cassandra vnodes and scale horizontally by adding more nodes. A demo video is available on youtube.

News

Project documentation is available at doc.elassandra.io.

2017-01-15 Release 2.4.2-4 Upgrade to Cassandra 3.0.10
2016-12-25 Release 2.4.2-2 Upgrade to Elasticsearch 2.4.2 + pass 3000 unit tests from Elasticsearch
2016-10-24 Release 2.1.1-18 Add multi-threaded index rebuild and optimized search routing (see RandomSearchStrategy)
2016-09-05 Release 2.1.1-17 Add spark support with a modified version of elasticsearch-hadoop-2.2
2016-08-12 Release 2.1.1-16 Upgrade to cassandra 2.2.7
2016-07-10 Release 2.1.1-15 Bug fix
2016-06-21 Release 2.1.1-12 Add support for index partitioning and cross-datacenter mapping replication
2016-05-10 Release 2.1.1-9 Upgrade to cassandra 2.2.5
2016-04-17 Release 2.1.1-8 New feature, index cassandra static columns
2016-03-18 Release 2.1.1-6 Add support for SQL plugin (from NLPchina) and JDBC driver (from Anchormen).
2016-02-16 Release 2.1.1-2 Remove build dependency to elasticsearch parent project.
2016-02-01 Release 2.1.1-1 Add support for parent-child relationship.
2016-01-28 Release 2.1.1 based on Elasticsearch 2.1.1 and cassandra 2.2.4.
2015-12-20 Release 0.5 Re-index you data from cassandra 2.2.4 with zero downtime.
2015-11-15 Release 0.4 New elassandra tarball ready-to-run.

Benefits of Elassandra

For cassandra users, elassandra provides elasticsearch features :

Cassandra update are automatically indexed in Elasticsearch.
Full-Text and spatial search on your cassandra data.
Real-time aggregation (does not require Spark or Hadoop to group by)
Provide search on multiple keyspace and tables in one query.
Provide automatic schema creation and support nested document using User Defined Types.
Provide a read/write JSON REST access to cassandra data (for indexed data)
There are many elasticsearch plugins to import data in cassandra or to visualize your data, with Kibana for example.

For Elasticsearch users, elassandra provides useful features :

Change the mapping and re-index your data from cassandra with zero downtime.
Cassandra could be your unique datastore for indexed and non-indexed data, it's easier to manage and secure. Source documents are now stored in Cassandra, reducing disk space if you need a noSql database and elasticsearch.
In elassandra, Elasticsearch is masterless and split-brain resistant because cluster state is now managed within a cassandra lightweight transactions.
Write operations are not more restricted to one primary shards, but distributed on all cassandra nodes in a virtual datacenter. Number of shards does not limit your write throughput, just add some elassandra nodes to increase both read and write throughput.
Elasticsearch indices can be replicated between many cassandra datacenters, allowing to write to the closest datacenter and search globally.
The cassandra driver is Datacenter and Token aware.
Hadoop Hive, Pig and Spark support with pushdown predicate.
Cassandra supports partial update and distributed counters.

Quick start

Ensure your JAVA_HOME points to your JDK 8 installation.
Extract the distribution tarball in your install directory.
Define the CASSANDRA_HOME environment variable: export CASSANDRA_HOME=<elassandra_install_dir>
Load useful aliases : source $CASSANDRA_HOME/bin/aliases.sh
Start a node: $CASSANDRA_HOME/bin/cassandra -e (or elstart alias)
Check the Cassandra status: $CASSANDRA_HOME/bin/nodetool status
Check the Elasticsearch cluster state: curl -XGET localhost:9200/_cluster/state (or state alias)

Support

Support available via elassandra google groups.
Post feature requests and bugs on https://github.com/vroyer/elassandra/issues

Contribute

Contributors are welcome to test and enhance Elassandra.

License

This software is licensed under the Apache License, version 2 ("ALv2"), quoted below.

Copyright 2015-2016, Vincent Royer (vroyer@vroyer.org).

Licensed under the Apache License, Version 2.0 (the "License"); you may not
use this file except in compliance with the License. You may obtain a copy of
the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
License for the specific language governing permissions and limitations under
the License.

Acknowledgments

Elasticsearch and Kibana are trademarks of Elasticsearch BV, registered in the U.S. and in other countries.

passyt / elassandra