Install Cassandra on Ubuntu

1. Make sure java has install
java -version

2.Add DataStax repository to source file(/etc/apt/sources.list).
deb http://debian.datastax.com/community stable main

3. Add DataStax repository key to your aptitude trusted keys.
curl -L http://debian.datastax.com/debian/repo_key | sudo apt-key add -

4. Update the repository
sudo apt-get update

5. Install Cassandra
sudo apt-get install dcs<versiton> (ex. sudo apt-get install dcs20 )

6. Login to the CQL console
cqlsh

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