How to Install Cassandra on Ubuntu 16.04 LTS

Apache Cassandra is a free open-source database system that is NoSQL based; This means that Cassandra does not use the table model seen in MySQL, MSSQL or PostgreSQL, but instead uses a cluster model. It's designed to handle large amounts of data and is highly scalable. In this tutorial, we will be installing Cassandra and its prerequisites, Oracle Java, and if necessary the Cassandra drivers.

Pre-Flight Check

• We are logged in as root on an Ubuntu 16.04 VPS server powered by Liquid Web!

• Apache Cassandra and this article assume that you are using Oracle Java Standard Edition 8, as opposed to OpenJDK. Please verify your version of Java by typing the command below into your terminal:

java --version

• At the time of this article, Python 2.7.11 and later versions will need to install updated Cassandra drivers to fix a known bug with the cqlsh command. You can check your Python version similar to checking your Java version:

python --version

• If you have Python 2.7.11+ or later, download the required driver by running the pip command. You will need pip installed. Within this tutorial, we will show you how to install pip. However, pip is usually pre-installed with Python by default.

Installation of Apache Cassandra

Step 1: Install Oracle Java (JRE)

Cassandra requires your using Oracle Java SE (JRE) installed on your server. First, you will have to add Java from the Oracle website. Once downloaded, run the installer and when complete, verify the default version of Java by typing:

java -version

You'll receive the following or something very similar :

Step 2: Installing Apache Cassandra

First, we have to install the Cassandra repository to /etc/apt/sources.list.d/cassandra.sources.list directory by running following command (When we made this article Cassandra 3.6 was the current version. You may need to edit this line to reflect the latest release by updating the 36x value. For example, use 37x if Cassandra 3.7 is the newest version.):
echo "deb http://www.apache.org/dist/cassandra/debian 36x main" | sudo tee -a /etc/apt/sources.list.d/cassandra.sources.list

Next, run the cURL command to add the repository keys :

curl https://www.apache.org/dist/cassandra/KEYS | sudo apt-key add -

We can now update the repositories:

sudo apt-get update

Finally, finish installing by entering the following:
sudo apt-get install cassandra

Verify the installation of Cassandra by running:
nodetool status

The desired output will show UN meaning everything is up and running normally.

Step 3: Connect with cqlsh

If you have an older version of Python before 2.7.11, you'll skip this step and start using Cassandra with the cqlsh command. Good for you! You have successfully installed Cassandra!
cqlsh

You should see something similar to this:
Connected to Test Cluster at 127.0.0.1:9042.
[cqlsh 5.0.1 | Cassandra 3.6 | CQL spec 3.4.2 | Native protocol v4]
Use HELP for help.

However, if you get the following error,

Connection error: ('Unable to connect to any servers', {'127.0.0.1': TypeError('ref() does not take keyword arguments',)}),

you'll update the Cassandra drivers. These drivers have a known bug with Cassandra and later versions of Python. Check your Python version by typing:
python --version

Luckily, I am going to show you how you can fix this error in 3 easy steps by downloading the drivers.

Step 3a:First we will need pip installed. If you don't have it already, you can get it with the following command.

sudo apt-get install python-pip

Step 3b

Once pip is installed, run the following to install the new Cassandra driver. Please note this command may take a while to execute. Grab a snack and wait for it to complete. It can take 5-10 minutes to install fully.

pip install cassandra-driver

Step 3c

Finally disable the embedded driver by entering :

export CQLSH_NO_BUNDLED=true

You should now be able to run the cqlsh command.

cqlsh

You should see this if successful :

Connected to Test Cluster at 127.0.0.1:9042.
[cqlsh 5.0.1 | Cassandra 3.6 | CQL spec 3.4.2 | Native protocol v4]
Use HELP for help.

To exit cqlsh type exit:
cqlsh> exit

Congrats! You have successfully installed Cassandra!