As virtualized infrastructure and cloud computing force businesses to reevaluate the broader issue of acceptable network service levels, open source network monitoring tools are attracting heightened interest.
Both network administrators and open source advocates say the flexibility these tools promise at a relatively reasonable cost has made them a viable alternative to software offered by some of the largest enterprise technology companies.
"When I first needed a network monitoring tool, I had no funding for a commercial alternative," said David Nalley, a Unix administrator for document management solution provider KeyMark in Liberty, S.C., who uses the Zenoss open source management tool.
Zenoss, which recorded a 150% increase in revenue during 2009, counts 300 enterprise customers and more than 1 million downloads of its Zenoss Core open source project code. Another well-known player is Nagios, which has inspired a community of more than 1,700 add-ons that IT departments can use to assemble an application specific to all the unique nuances of their particular network.
Actually, there are literally dozens of different open source projects focused on the problem of network monitoring. Snort, developed by Sourcefire, boasts 270,000 registered users and millions of downloads. Cacti works with MySQL to provide network graphing. The Stanford Linear Accelerator Center provides a list of open source network monitoring tool projects that is updated relatively frequently.
Open source network monitoring tools enable monitoring fine tuning
Beyond price, users are as attracted to the ability to tailor these tools to their specific networks and applications and bounce those ideas off others in the open source community.
"The software offers a level of customization that doesn't exist in more traditional commercial products," Nalley said. "The other thing is that unlike most of the proprietary products, there is an incredible community. There is always someone there to help."
Customization capabilities could come in the form of supporting devices and technologies particular to the KeyMark network, he said, or in the ability to create scripts that test the performance of certain applications.
Ethan Galstad, president of open source monitoring provider Nagios Enterprises in Minneapolis, said the traditional motivation for Nagios users and customers is flexibility -- their ability to monitor not only more common infrastructures such as the gamut of Windows servers but also devices and equipment that aren't supported by some of the well-known prepackaged systems management tools. Nagios is well known among the education, financial and healthcare industries, Galstad said.
Philip Martin, director of client services for Symbio Systems, an outsourcing company in San Jose, Calif., works with Groundwork Open Source, which has built an open source network and infrastructure product called Groundwork Monitor by combining features of various tools from the open source community.
"Everyone's infrastructure is just a little bit different; and with open source, I can usually find ways to make templates and replicate changes in ways that aren't complicated," Martin said. "I can be confident that I can change something as my network changes."
So, for example, as new equipment is added or new applications are deployed, this shouldn't get in the way of effective monitoring.
Answering the SLA call with open source network monitoring tools
Another driving motivator for companies to invest in open source network monitoring tools is the emerging need to prove a higher level of accountability and monitor against service-level agreements (SLAs). Networking teams find themselves monitoring SLAs that are part of contracts for software as a service (SaaS), such as Salesforce.com, and even living up to internally created SLAs as they build out their own clouds.
"Application monitoring and reporting has become crucial," Nalley said. "I care about [whether] the machines went down and why; my boss wants to know if we achieved certain uptime requirements."
Open source tools can communicate with everything from environmental monitoring devices that keep tabs on the load being supported by HVAC to e-commerce and Web applications that cannot tolerate a moment of downtime.
"The cloud is really pushing people to consider open source. Application monitoring becomes really important during this transition. So many more applications are obviously both inward-facing and outward-facing," said Peter Jackson, CEO of San Francisco-based GroundWork.
Prepackaged tools weren't necessarily designed to deal with environments that are constantly changing, noted Mark Hinkle, vice president of community for Zenoss. There are more than 175 extensions for the Zenoss tool, he said. "We're flexible enough to monitor whatever you want."
Less cost, more work in open source network monitoring tools
Open source vendors and users also say cost has become a much bigger factor over the past six months, as IT departments look to streamline operating budgets. Community editions of open source are technically free, of course, but commercial versions carry a price tag pinned to receiving upgrades and some level of support. The commercial editions of Nagios, for example, typically run from $600 to $1,300. Pricing for software from the big-name network management software vendors is a more complicated proposition, one that varies with the assets being managed. Costs can easily mushroom into thousands of dollars per organization, according to network managers.
Customization would carry another fee, which is one potential drawback of open source network monitoring tools. "With a traditional monitoring or alarming vendor, I would expect what I get to be really, really easy to use," Martin said. "I would expect support, because I am paying for it. And I would expect there to be more stringent developer controls on the products. Sometimes you get divergent coding standards."
Nagios' Galstad cautions that organizations may need a highly technical person on staff to extend his commercial platform, which he believes "hits about 90% of what they need out of the box."
"There's more onus on you to make things work when you are dealing with true open source," Nalley added. "You have to invest the time to do things yourself. On the other hand, you end up knowing your environment a lot better."