A movement's afoot among management software providers to move from traditional agent-based management schemes to an agentless management approach. The idea is to give data center managers more control over making changes to their IT infrastructure. But not everyone is convinced the agentless approach is all some vendors are making it out to be.
The traditional method of managing equipment is to put an agent (monitoring software) on each piece of hardware. Agents need to be installed on each server and IT staff has to update them whenever hardware or software is upgraded.
Agent-based systems use software to monitor each individual piece of equipment, and those agents need to be installed and updated. The process was too much work, so IT shops opted to cover only certain pieces of hardware, leaving holes in the coverage.
An agentless system, on the other hand, monitors equipment across the entire network, and while it has the capability to throw a wider net, it cannot perform tough fixes that an agent-based system could.
According to Kevin Strehlo, vice president of marketing for Integrien Corp., a management software company in Pasadena, Calif., the maintenance burden of deploying agents across an increasingly distributed environment becomes so great that IT staff only monitors critical systems.
The problem with a limited coverage approach is that something can go wrong anywhere in the transaction in a complex environment.
"The problem might crop up in an application server, Web server or some other device you don't have an agent on. You need absolute full coverage," Strehlo said.
But despite these problems, agent-based systems are here to stay -- for now.
Today, many agentless management systems are brought into an environment where an agent-based management system, such as IBM's Tivoli or Hewlett-Packard Co.'s OpenView, is already installed. The agentless system finds a problem and sends an alert to an agent-based management tool to go down deep within a particular piece of equipment.
Robert Simpson, Web hosting manager at Deerfield Ill.-based Baxter Healthcare, uses this combined approach. His organization purchases managed services from IBM, which uses BMC Software Inc.'s Patrol and HP's OpenView, both of which are agent-based systems. But Simpson needed an agentless system to perform specific functions.
"We have five machines running Web and application servers behind the load balancer, powering 20 Web sites. The agent could only monitor them through the load balancer, which of course is designed to hide problems." Simpson said. "The answer was an agentless system."
Simpson uses Integrien's Alive 5.0 behind the load balancer to monitor what had been a black hole. It sends a URL to a specific server and the server processes it like any other request, allowing Simpson to see if any of the application servers are not responding.
Simpson said adding Alive improved the responsiveness of his managed services generally.
"We'd been having a problem from the application layer up, and [the managed services provider] simply didn't have a tool that could tell us what was wrong," Simpson said. "Besides, if an agent goes to sleep and doesn't wake up, the monitoring server would never know. With Alive, I can look at everything, from high-level statistics all the way down to a specific process, and expand our infrastructure on-demand without the need to install new agents."
Luckily for data center pros in Simpson's position, the number of agentless tools is growing.
There are several agentless monitoring tools on the market, including Mountain View, Calif.-based Mercury Interactive Corp.'s SiteScope offering, Integrien's flagship product Alive 5.0 and Houston-based BMC's new Performance Manager. BMC is the first management software vendor with major market presence to embrace agentless technology.
Cambridge, Mass.-based Forrester Research Inc. has predicted the success of agentless management, hailing the transition from agent based to agentless as bridging the gap "between today's jumble and organic IT."
"Collecting data on infrastructure components has been the foundation of any type of management software -- until now. … Tomorrow, buyers will emphasize intelligent management layers rather than raw data collection capabilities. This trend is already apparent in new products from BMC Software," said Forrester analyst Jean-Pierre Garbani, in a recent report titled, "Agentless Management Comes Of Age."
But others aren't as convinced.
"There tend to be tradeoffs," said Gordon Haff, senior analyst with Nashua N.H.-based Illuminata. "There's installation energy associated with installing an agent on every piece of equipment you want to monitor. On the other hand, it gives you more management power. You can perform higher level observation using agentless discovery mechanisms, but you don't have a whole lot of control."
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