Apache Cassandra is a NoSQL database intended for storing large amounts of data in a decentralized, highly available cluster. NoSQL refers to a database with a data model other than the tabular relations used in relational databases such as MySQL, PostgreSQL, and Microsoft SQL.
- These instructions are intended for installing Cassandra 2 on a single CentOS 6 node.
- I’ll be working from a Liquid Web Core Managed CentOS 6.4 server, and I’ll be logged in as root.
- You may be able to skip to Step #2 if you already have a stable version of Java 7 (preferably the Oracle/Sun JVM). Check to see if your server already has Java installed by running the following command: java -version
Head over to Oracle’s website and get the latest version of Oracle Java SE Runtime Environment 7.
Accept the license agreement and then download the Linux x64 RPM installer (which as of the writing of this article is jre-7u45-linux-x64.rpm ) to your local desktop.
Transfer the file to your Liquid Web server. If you need help with that, check out this article: Using SFTP and SCP Instead of FTP
Login to the server as root, and then from the directory where you uploaded the package run the install by using the command rpm -ivh <filename>, or in this case:
rpm -ivh jre-7u45-linux-x64.rpm
Note: Your command will be slightly different if you downloaded a different version of Oracle Java SE Runtime Environment 7. Simply replace jre-7u45-linux-x64.rpm with the actual filename.
Then install the Java Native Access (JNA) which can improve Cassandra’s memory usage:
yum install jna
Add a symbolic link to the Oracle Java SE Runtime Environment 7 installation so that your server uses the Oracle JRE instead of the OpenJDK JRE:
alternatives --install /usr/bin/java java /usr/java/jre1.7.0_45/bin/java 20000
Note: Your command will be slightly different if you downloaded a different version of Oracle Java SE Runtime Environment 7. Simply replace jre1.7.0_45 with the actual version you’ve installed.
Then use the alternatives command to verify that the Oracle Java SE Runtime Environment 7 is selected. If not, simply choose the appropriate Selection after you run the command:
alternatives --config java
Utilize the following command to double check the correct version of Oracle Java SE Runtime Environment 7 is being used:
For a refresher on editing files with vim see: New User Tutorial: Overview of the Vim Text Editor
Add the following information to the file you’ve created, using i to insert:
name = DataStax Repo for Apache Cassandra
baseurl = http://rpm.datastax.com/community
enabled = 1
gpgcheck = 0
At this point, installing Cassandra is as simple as running just one command:
yum install dsc20
Just two more simple environment tweaks that enable Cassandra to run correctly:
Note: Your commands will be slightly different if you downloaded a different version of Oracle Java SE Runtime Environment 7. Simply replace jre1.7.0_45 with the actual version you’ve installed.
service cassandra start
Check Cassandra Service Status
service cassandra status
Enter the Cassandra Command Line
Check Cassandra Node Status
service cassandra stop
There are many, many more things we could say about Cassandra, but those will be detailed in follow-up articles in the Liquid Web Knowledge Base! Look for articles on: How To Install Cassandra 2 and Run a Multi-Node Cluster on CentOS 6 , Recommended Production Settings for Cassandra on CentOS 6 and more!