Understanding the Computer Model in Service Manager

Service Manager models computers as a set of classes with relationships between them like this.  The lines with the arrow heads indicate class derivation (or “specialization”).  The other lines indicate relationships.


The way to read this model diagram is that conceptually there is a Windows computer (represented by the Microsoft.Windows.Computer class). In an Active Directory environment, each Windows computer has a Fully Qualified Domain Name which is represented as the PrincipalName property. This property is the key property of the Microsoft.Windows.Computer class meaning that every Windows computer is uniquely identified by this name. The Microsoft.Windows.Computer object captures information about the Windows computer itself which can be different about each Windows computer regardless of which physical host it is running on.

Each Windows Computer runs on a physical computer which is represented as a Microsoft.SystemCenter.ConfigurationManager.DeployedComputer in the model. Any given Microsoft.SystemCenter.ConfigurationManager.DeployedComputer can run multiple Windows computers given multi-boot scenarios or even the new “boot to VHD” option in Windows 7/Server 2008 R2. The Microsoft.SystemCenter.ConfigurationManager.DeployedComputer tracks information about the physical aspects of the hardware.

Every Windows computer also hosts some logical hardware such as Physical Disks, Logical Disks, Disk Partitions, Network Adapters, and Processors. Any given Windows computer can have one or many of these logical hardware components.

Every Windows computer also hosts a single Operating System instance. The Operating System class captures information about the Operating System itself. Because the Operating System is a hosted class where there is only ever one Operating System object per Windows Computer, you can think of the Operating System as just an extension of the Windows computer.

Generally speaking, people manage things at the Windows computer level. It is the logical unit of management that most people understand. Conceptually this means that whenever a user is talking about a Windows computer he is actually talking about the Microsoft.Windows.Computer object and its hosted Operating System, hosted logical hardware, and the physical computer that it is running on.

Extending the model further, Provance provides for a hardware asset record which captures information about the physical computer from an asset lifecycle perspective. Hardware asset records typically are inserted into the system before the asset ever even is delivered, powered on, and networked up. The hardware asset record captures information such as cost, warranty expiration, vendor (not manufacturer necessarily), etc. Provance provides a workflow out of the box that can be configured to automatically match up hardware asset records with Microsoft.SystemCenter.ConfigurationManager.DeployedComputer records based on matches in Serial Number, MAC Address, or AssetTag. When these matches are discovered a relationship is automatically created between the hardware asset and the Microsoft.SystemCenter.ConfigurationManager.DeployedComputer . This linkage makes it possible to answer questions like “How much did computer1.mycompany.com cost?” or “Where did we buy computer1.mycompany.com from?” or even “When do all of the warranties expire for all our computers running Windows Server 2003?”.

Server Rename Process

When a computer is renamed or the computer is moved from one domain to another, the computer FQDN will change. This results in SCOM discovering this as a new computer. SCSM therefore treats it as a new computer as well. This new computer will have a new relationship to the same Microsoft.SystemCenter.ConfigurationManager.DeployedComputer (physical computer) though. At this point you would have two Windows computers (oldname.mycompany.com and newname.mycompany.com) related to the same Microsoft.SystemCenter.ConfigurationManager.DeployedComputer . The oldname.mycompany.com computer doesn’t go anywhere. It remains in the SCSM CMDB. The proper thing to do would be to mark the oldname.mycompany.com computer as Status = Renamed or something like that and relate it to the newname.mycompany.com computer for easy reference. The history of property and relationship changes for oldname.mycompany.com and its relationships to other CIs and work items like incidents, change requests, and so on remain intact. In reports you could merge this information together using queries over the relationships into what looks like a single computer if that was required. The relationship of the Windows computer and the hardware asset record remains intact because the hardware asset record is related to Microsoft.SystemCenter.ConfigurationManager.DeployedComputer which has remained unchanged because it is the physical computer.