About Cassandra: Cassandra/ Apache Cassandra is scalable NoSQL database system. It is used to manage large amount of structured, semi-structured and non structured data. I am writing this blog which will help you to install and run a single-node cluster on Ubuntu 14.04. Cassandra's architecture allows to connect and access data using the CQL language. CQL uses a similar syntax to SQL.

Step 1: Installing Oracle Java Virtual Machine

$ sudo add-apt-repository ppa:webupd8team/java

Update the package database:

$ sudo apt-get update

Now install the Oracle JRE. When prompted, accept the license agreement:

$ sudo apt-get install oracle-java8-set-default

After installing it, please do verify that it's the default JRE:

Output
java version "1.8.0_60"
Java(TM) SE Runtime Environment (build 1.8.0_60-b27)
Java HotSpot(TM) 64-Bit Server VM (build 25.60-b23, mixed mode)

Step 2 -- Installing Cassandra

Change the 22x to match the latest version. For example: Use 23x or 24x if Cassandra 2.3  or 2.4 is the latest version:

echo "deb http://www.apache.org/dist/cassandra/debian 22x main" | sudo tee -a /etc/apt/sources.list.d/cassandra.sources.list

Now add the repository source:

echo "deb-src http://www.apache.org/dist/cassandra/debian 22x main" | sudo tee -a /etc/apt/sources.list.d/cassandra.sources.list

Now Add three public keys with the package repositories to avoid package signature warnings during package updates

gpg --keyserver pgp.mit.edu --recv-keys F758CE318D77295D
gpg --export --armor F758CE318D77295D | sudo apt-key add -

Now add the second key:

gpg --keyserver pgp.mit.edu --recv-keys 2B5C1B00
gpg --export --armor 2B5C1B00 | sudo apt-key add -

Then add the third key:

  gpg --keyserver pgp.mit.edu --recv-keys 0353B12C
  gpg --export --armor 0353B12C | sudo apt-key add -

Now please update the package database once again:

sudo apt-get update

Now final step is to update Cassandra

sudo apt-get install cassandra

Step 3: Troubleshooting and Starting Cassandra

Cassandra is installed now and it will not start at this point due to some bugs that we need to fix it. To confirm cassandra is not running run following command:

sudo service cassandra status

If Cassandra is not running then it will show you the following output:

Output
* could not access pidfile for Cassandra

Now we will fix bugs that come after installation is completed

sudo nano +60 /etc/init.d/cassandra

That line should read:

/etc/init.d/cassandra
CMD_PATT="cassandra.+CassandraDaemon"

Change it to:

/etc/init.d/cassandra

CMD_PATT="cassandra"

Now close and save the file, then reboot the server:

sudo reboot

After logging back, Cassandra should be running now.

sudo service cassandra status

If Cassandra is running successfully then you will see the following output:

Output
* Cassandra is running

Step4: Connecting to Cluster:

If you were able to successfully start Cassandra, check the status of the cluster:

sudo nodetool status

Output
Datacenter: datacenter1
=======================
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
--  Address    Load       Tokens       Owns    Host ID                               Rack
UN  127.0.0.1  142.02 KB  256          ?       2053956d-7461-41e6-8dd2-0af59436f736  rack1

Note: Non-system keyspaces don't have the same replication settings, effective ownership information is meaningless

Then connect to it using its interactive command line interface cqlsh.

$ cqlsh

You will see it connect:

Output
Connected to Test Cluster at 127.0.0.1:9042.
[cqlsh 5.0.1 | Cassandra 2.2.2 | CQL spec 3.3.1 | Native protocol v4]
Use HELP for help.
cqlsh>

Now type exit to quit:

cqlsh> exit

All done! You now have a single-node Cassandra cluster running on Ubuntu 14.04.

Thanks for reading blog