Like many other software packages, MOM and OpsMgr can deploy an agent to the system being monitored. Whether or not to deploy agents in general is always a discussion point. Let's talk about the agent used by Operations Manager.
While Operations Manager can use agentless monitoring, most management packs are built to perform better with an agent. The rules and other managment pack objects are deployed to each agent that they pertain to, allowing monitoring to occur even if contact is lost with the management server. Without an agent, the agent component on the management server collects data from the agentless managed computer using remote calls to that system. If the two systems cannot communicate, information is not collected.
In some cases, any change to a computer may lead to complications. While sometimes these complications are more political than operational, the IT group may want to avoid even the appearance of affecting an applicaiton server to avoid potential liability. Agentless sytems have a more limited set of features than do agent-based managed computers. Some mangement packs will not even run agentless. This list includes:
Other management packs such as SQL Server can run agentless but with reduced functionality.
For Operations Manager, agentless monitoring is recommended only when an agent-managed configuration is not possible. While agentless monitoring may decrease the load on the monitored system, it increases the resource load on the managment server monitoring that system. It also leads to increased network utilization when the data is sent across the pipe, is not as reliable in collecting data as using agent-monitored systems, and has reduced management capability.
For other discussions on agent-based vs. agentless in general, see http://www.networkworld.com/news/2007/102607-arguments-agent-based-agentless.html?nwwpkg=50arguments.
Kerrie Meyler, MVP, MCSE, MCTS, CNA, MA, BA, is an independent consultant and trainer with over fifteen years of experience in IT. While at Microsoft in Field Technical Sales for four years she focused on infrastructure and mangement, presenting at numerous product launches. Kerrie has presented Operations Manager 2007 at TechEd 2007 and MMS 2009 and at internal Microsoft conferences, receiving company recognition and awards including a SPAR MGS award. Kerrie worked with Microsoft Learning to develop functional specifications for the original Operations Manager Microsoft courseware, 2550: Implementing Microsoft Operations Manager 2000 and did the beta teach for that course.She also participated in the alpha walkthrough for the 70-400: Configuring Microsoft System Center Operations Manager certification exam.
She is the lead author of Microsoft Operations Manager 2005 Unleashed, Microsoft System Center Operations Manager 2007 Unleashed, and Microsoft System Center Configuration Manager (SCCM) 2007 Unleashed. Kerrie is currently developing an eBook on Operations Manager 2007 R2.
Check out an excerpt from System Center Operations Manager 2007 Unleashed, Chapter 3: Looking Inside OpsMgr.
Kerrie's latest book, System Center Configuration Manager (SCCM) 2007 Unleashed by Kerrie Meyler, Byron Holt, and Greg Ramsey has been selected as the August, 2009, Microsoft Subnet book giveaway (a $59.99 value). Check out an excerpt from System Center Configuration (SCCM) Manager 2007 Unleashed, Chapter 3: Looking Inside ConfigMgr.
Visit the Microsoft Subnet home page for giveaway details and entry forms.
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Good stuff!
Hey Kerrie, this is an excellent overview on agent versus agentless monitoring. I was working on a similar concept and scrapped some sections of mine because you have this mapped out so clearly here. Thanks for writing this up! My blog article on this is available at http://cameronfuller.spaces.live.com/blog/cns!A231E4EB0417CB76!1044.entry