Cassandra provides built-in support for Hadoop. If you have ever written a MapReduce program, you will find out that writing a MapReduce task with Cassandra is quite similar to how one would write a MapReduce task for the data stored in HDFS. Cassandra supports input to Hadoop with
ColumnFamilyInputFormat and output with
ColumnFamilyOutputFormat classes, respectively. Apart from these, you will need to put Cassandra-specific settings for Hadoop via
ConfigHelper. These three classes are enough to get you started. One other class that might be worth looking at is
BulkOutputFormat. All these classes are under the
To be able to compile the MapReduce code that uses Cassandra ...