Google for Logfiles
“Splunk is the ‘Google search engine’ for machine data.” That’s how Erik Swan, Splunk’s CTO and co-founder of Splunk, described it in an interview.
In simple terms, Splunk can make machine data work better, smoother, faster and cheaper, whether it’s the company’s own IT infrastructure or a Cloud service. Behind the structure of what you see on Facebook, Twitter, YouTube, Amazon, LinkedIn, or any other web site for that matter, the crux of information resides in a hidden universe of unstructured data. Splunk enables businesses to collect, organizes and analyze this very unstructured machine data and represents a clean business-to-business play on the emerging Internet-of-Things space.
Splunk offers logical, intuitive and human-centric analytics for operational intelligence. Most importantly, it is a seamless analytics, monitoring and data visualization tool that helps you improve business capabilities by making intuitive sense out of vast quantities of unstructured data. While doing this, Splunk permits simple Google-like queries and answers about how any IT system is operating. The field of unstructured and meta-data analytics is the next phenomenon in what computing enables and Splunk is a promising leader in this burgeoning domain.
What do you do when you need information about the state of a machine or software? You look at its logfiles. They tell you the state it is in and what happened recently. Great.
What do you do when you need information about the state of all devices in your data center? Looking at all logfiles would be the right answer if it was possible in any practical amount of time. This is where Splunk comes in.
Splunk started out as a kind of “Google for Logfiles”. It does a lot more today but log processing is still at the product’s core. It stores all your logs and provides very fast search capabilities roughly in the same way Google does for the internet.
Search Processing Language
Although you can just use simple search terms, e.g. a username, and see how often that turns up in a given time period Splunk’s Search Processing Language (SPL) offers a lot more. SPL is an extremely powerful tool for sifting through vast amounts of data and performing statistical operations on what is relevant in a specific context. Think SQL on steroids. And then some.
For example you might want to know which applications are the slowest to start up, making the end user wait the longest. The following search answers that. First the relevant data is selected by specifying a so-called sourcetype (“ProcessStartup”). The result of this sub-command is piped (“|”) to another command that groups the data by application (“by Name”), calculates the average for each group (“avg(StartupTimeMs)”) and charts the results’ distribution over time (“timechart”):
index=uberagent sourcetype=uberAgent:Process:ProcessStartup | timechart avg(StartupTimeMs) by Name
The result is something like this:
Apps, Add-ons and Data Sources
Reading the above you might wonder how Splunk knows about the duration of application starts. And you are right: by itself it does not know anything. But it can receive data from a variety of sources: all kinds of log files, Windows event logs, Syslog, SNMP, to name a few. If the data you need cannot be found in any log you can write a script and direct Splunk to digest its output. If that still is not enough you should check Splunk’s App Directory for an add-on that collects the necessary data. In the example above the data was generated by uberAgent, our Windows monitoring agent. uberAgent runs on the monitored endpoints independently of Splunk and sends the data it collects to Splunk for storage and further processing.
Splunk apps can be data inputs, but they can also contain dashboards that visualize what has been indexed by Splunk. In case of uberAgent both types are used: the actual agent acts as a data input while the dashboard app presents the collected data to the user. The former runs on the monitored Windows machines, the latter on your Splunk server(s).
Index, (no) Schema, Events
When first hearing about Splunk some think “database”. But that is a misconception. Where a database requires you to define tables and fields before you can store data Splunk accepts almost anything immediately after installation. In other words, Splunk does not have a fixed schema. Instead, it performs field extraction at search time. Many log formats are recognized automatically, everything else can be specified in configuration files or right in the search expression.
This approach allows for great flexibility. Just as Google crawls any web page without knowing anything about a site’s layout, Splunk indexes any kind of machine data that can be represented as text.
During the indexing phase, when Splunk processes incoming data and prepares it for storage, the indexer makes one significant modification: it chops up the stream of characters into individual events. Events typically correspond to lines in the log file being processed. Each event gets a timestamp, typically parsed directly from the input line, and a few other default properties like the originating machine. Then event keywords are added to an index file to speed up later searches and the event text is stored in a compressed file sitting right in the file system.
Scalability, (no) Backend
That brings us to the next point: there is no backend to manage, no database to set up, nothing. Splunk stores data directly in the file system. This is great for a number of reasons:
Installation is superfast. Splunk is available for more platforms than I can name here, but on Windows you run the installer, click next a few times and you are done in less than five minutes.
Scalability is easy. If a single Splunk server is not enough you just add another one. Incoming data is automatically distributed evenly and searches are directed to all Splunk instances so that speed increases with the number of machines holding data. Optionally redundancy can be enabled, so that each event is stored on two or more Splunk servers.
No single point of failure. I have seen too many environments where an overloaded database server slowed down half the applications in the data center without anyone finding the root cause. While this is a great use case for uberAgent my point is that this will not happen with Splunk.
Infinite retention without losing granularity. Some monitoring products only allow you to keep so many months, weeks or even days worth of data. Others reduce the granularity of older events, compressing many data points into one because of capacity limits. The same is not true for Splunk. It can literally index hundreds of terabytes per day and keep practically unlimited amounts of data. If you want to or need to compare the speed of last year’s user logons with today’s: go ahead!
Licensing, Download, Getting Started
Licensing in a nutshell: Splunk limits the amount of new data that can be indexed per day. A free version is available that is capped at 500 MB / day. When buying Splunk Enterprise licenses you buy daily indexed data volume, in other words gigabytes that can be added to Splunk per day. The number of Splunk servers the data is being stored on, how long you keep the data or over which periods of time you search is entirely up to you. Once the data is indexed, it is yours.
The Phenomenal Growth of Splunk
- More than 9,000 enterprises, government agencies, universities, and service providers in more than 100 countries use Splunk software to deepen business and customer understanding, mitigate cyber security risk, prevent fraud, improve service performance, and reduce costs.
- Splunk has captured a whopping 10% of the Big Data Analytics market within just eight years of its launch. (Source: Forbes)
- Vodafone uses Splunk to make sure its routers and system behaves, and to watch for and deal with virus attacks that can be notoriously sneaky and hard to find with traditional monitoring.
- Splunk has 537 apps to make sense of almost every format of log data, from security to business analytics to infrastructure monitoring.
Features That Make Splunk the Google of Unstructured Data:
- Log processing is one of the core competencies of Splunk. It stores all your logs and provides very fast search capabilities roughly in the same way Google does for the internet device log files.
- The Search Processing Language (SPL) for Splunk is an extremely powerful tool for extracting meaning out of vast amounts of data and performing statistical operations on what is relevant in a specific context.
- Splunk indexes any kind of machine data that can be represented as text and there is no need to define tables and fields before you can store data. Splunk does not have a fixed schema. In fact, it performs field extraction at search time. This aspect allows for great flexibility.
- Splunk does not reduce the granularity of older events, compressing many data points into one because of capacity limits. It can seamlessly index hundreds of terabytes per day and keep practically unlimited amounts of data.
- Splunk dashboards allow you to monitor all of your systems at once, so when a problem occurs you can start looking for a solution even before the problem starts bothering the system, or even better, the Splunk dashboard allows to clearly look for signs of a possibly arising problem.
The top five industries hiring Big Data related expertise include Professional, Scientific and Technical Services, Information Technologies, Manufacturing, Finance and Insurance and Retail Trade. Within Big Data related jobs, the ones pertaining to unstructured machine data & the internet-of-things has seen a whopping jump to 704% around the world over the last five years. (Source: Forbes)
This is a fulfilling time to start with Splunk jobs and ride the Big Data wave. With Splunk training, you can work as a Software Engineer, Systems Engineer or a Programming Analyst. With annual salaries lying within an impressive range of $84,000 to $120,000, Splunk is only going to empower and drive your IT career to phenomenal heights.