Splunk, in simple words, is a log analyzer, a powerful one. It understands machine data like no one else and make it searchable and displays it in easy to understand way with a web dashboard. This data is important not only for searches but also for investigations, monitoring and making decisions regarding your infrastructure. Large organizations like Motorola and Vodafone use splunk to keep an eye on their server and now I am going to show you, how you can do the same.
How to install Splunk?
To install splunk just download the relevant installer from this page and use a suitable package manager. I'll use Centos 5.6 for this post. So just do a "yum install splunk-4.2.3-105575.i386.rpm". The rpm will be installed in /opt/splunk. Chances are that it won't be in your path so either add it or just use the full path. If the splunk is not in the /opt run a find on it "find / -name splunk". To start splunk server just issue the command " /opt/splunk/bin/splunk start" and accept the license. Don't forget to allow the port, usually 8000, from you firewall.
Adding logs for analysis
Let us add apache logs to the splunk for analysis. These logs are located at /var/log/httpd/. Log in using the web console at http://localhost:8000 with credentials id: admin and password: changeme. Click on the "Add data" button and then on Apache logs link. Now you got to "Consume Apache logs on this Splunk server", click next and specify the path to the apache logs directory and you are done.
Searching through the logs
From home page go to the welcome tab and launch the search app. Now you just need to type the search query and the relevant parts from the logs will be presented to you.
From the search app only, click on the "Build Report" link and just specify the criteria and that is it. You'll get the report in no time.
And there it is. Splunk is good to go. Explore more and comment here. :)