System Center 2012 R2 Operations Manager uses either Agent-based or Agentless communication to collect data from servers and devices. Servers with agents will push this data to the management servers or gateways that they have been assigned to, while agentless managed servers and devices, such as network switches, earlier version of Windows operating system like windows 2003 sp1, windows 2000, Windows NT, will generally have their information pulled from management servers or watcher node.
The flow of information and/or connection points around the infrastructure can be visually represented as follows:
Below are the scenario where you can monitor the end device
Managed device reporting to management server:
For example your monitoring device directly reporting to management server.in this case let say if any event occurred on agent machine, SCOM agent will forward the alert to the SCOM management server for alerting. Once SCOM management server received the alert from the agent machine, it will write the data in operation database and data ware house database.
Managed device reporting to SCOM gateway server:
If you monitoring the DMZ or workgroup server or not trusted domain server in this case monitoring device can report to gateway server. Purpose of placing the gateway server is compression the data before sending to SCOM management server. Here SCOM agent will send the alert notification to SCOM gateway server and SCOM gateway server will compressing the data before sending to SCOM management server.
SCOM uses a mechanism known as management packs to control what type of information is collected and how to react to this information. These management packs are XML formatted files that define rules, monitors, scripts, and workflows for SCOM to use and essentially tell it how an aspect of your infrastructure should be monitored.
Most of these management packs will come from the suppliers of the software and devices used within your infrastructure, but there is nothing to stop you from creating your own management packs to fill a gap in monitoring if you find one.
You are also able to override predefined options within management packs to better tune the monitoring for your environment.
Monitoring Windows device through SCOM agent:
If you want to monitor windows server through SCOM with agent based monitoring, you need to install the agent the monitoring server. While installing the agent you have to specific the SCOM management group name and SCOM management server name. Remember port 5723 must be opened between SCOM agent and SCOM management server or gateway server. SCOM uses 5723 port for communicating with management/gateway server. After installing the SCOM agent you can see the agent health in SCOM operation console. If agent is healthy that means it’s ready for forwarding the alert to management/gateway server.
Monitoring Windows device through SCOM agentless:
As you know SCOM 2012 agent not supported on windows 2003 sp1and earlier version of windows operating system. Now monitoring older version operating system is biggest challenge. But no need to worry we can use agentless monitoring. You can discover the server from the any of the management server/gateway server from where you want to monitor. After successfully discovery of the server you can select agentless option for agentless monitoring. You can change the watcher node by any time.
Agentless monitoring is limited with up/down monitoring not more than that. Also you can use script to collect the data from agentless managed device.