AD integration in OpsMgr it is the ability for an OpsMgr agent to query active directory and know which management server it needs to report to.
It’s important to understand that this does not automate the deployment of the agent, but rather automates the configuration of Operations Manager agents that have been deployed by any of the preferred manual installation methods.
AD integration is useful for customers that have larger deployment of over a thousand agents and helps reduce manageability costs. By using AD integration you can specify the primary and secondary management server for agents. This is something that cannot be done using the familiar push agent deployment method from the SCOM console whereby users can only specify the primary management server.
A summary of what AD Integration can do is as follows:-
-AD integration automates the configuration of OpsMgr agents installed on AD member computers.
-Agent configuration information is maintained centrally in the OpsMgr console and published to the ADs.
-Agents are distributed to the servers manually, using software delivery methods or as part of the OS installation. When they are first started they pull their configuration from AD.
-Agent deployment and patching must be done outside of OpsMgr.
-Domain Controllers and already push installed agents cannot participate
Pete Zerger composed the following PowerPoint presentation on this subject which is a fantastic resource to help you understand how AD Integration works and how it is implemented:-