What’s a target and how do you “target” it? The answer varies depending on the version of Operations Manager (MOM 2005 or OpsMgr 2007) you are using. Several articles are available regarding this (including https://blogs.technet.com/momteam/archive/2007/10/31/targeting-series-part-1-differences-between-2005-and-2007.aspx and https://blogs.technet.com/ati/archive/2007/05/14/targeting-rules-and-monitors.aspx). As the topic delves into architectural differences between the two versions, the information is certainly worth discussion.
MOM 2005 had rule groups and computer groups. If a computer was in a computer group that was associated with a rule group, the rule applied to it. It was very straightforward. Of course, the rule was targeted at a computer that had characteristics pertaining to that rule – but might also have many other components that didn’t necessarily need to be governed by the logic in that rule. The association could be by a formula that examined registry entries, or might be a manual association made by a MOM administrator.
Rather than identifying specific computers (and targeting those agents), OpsMgr 2007 looks at the component that is generating the information. This is more granular, more powerful, and a totally different concept. OpsMgr determines which agents hold instances of the particular component, delivers the rule or monitor to the applicable agents, and executes the rule/monitor for each instance. Instead of targeting computer groups, you target specific classes. For example, if you want to monitor specific SQL Server objects, you create a monitor and then target it to the SQL Database class. Therefore, the monitor applies to each instance of the class on the agent, rather than just the agent. OpsMgr 2007 enumerates all instances of the target class and applies the rule/monitor to each. If there are no instances of that class on an agent, the rule does nothing.
So how do you actually target something? That’s the question isn’t it?
If you apply a rule or monitor directly to a group, it executes against the group itself and does not enumerate to the members of the group and apply the rule to each. This is a huge difference from MOM 2005.
To target a subset of components, you can either target it at a class – but that applies the rule to all instances of the class (which you may or may not want, depending on what you are trying to do!). The alternative is to create a rule target at the entire class, disable it, and then create a group with the objects you want and create an override for that group to enable your rule. So the answer, as usual, is “it depends.”
Hopefully though now, you have a better idea of how targeting does and can work.
