Windows Server 2008 R2 CSIT 320 (Blum) 1

Server Consolidation – Today’s chips have enhanced capabilities compared to those of the past. In particular they have multiple cores. – One “box” can now handle multiple services, but there was some benefit (in maintaining & updating) to having isolated servers. Virtualization provides (a kind of) isolation. – In addition to saving on the cost of the hardware itself, server consolidation can reduce power usage and in some environments reduce the amount of cooling needed. CSIT 320 (Blum) 2

 Testing  Having a collection of virtual machines allows one a convenient way to test software on a variety of systems (e.g. Windows XP, Vista, 7).  One can save (and even transport) the “state” of the machine allowing developers to see the results of the trials.  Scripting on the host allows much of the testing to be automated. CSIT 320 (Blum) 3

 Network Testing  The virtual machines can be grouped into a virtual network – allowing one to test various network scenarios CSIT 320 (Blum) 4

 Backup and Disaster Recovery  Since the “state” of the virtual machine can be saved and transported, this provide a mechanism for backing up not just user data but configuration settings and so on.  Then the backed up state can be used to recover from a disaster – providing a key step in one’s business continuity plan. CSIT 320 (Blum) 5

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 Many implementations use only two rings 0 and 3  Ring 0 (kernel mode, supervisor mode, “in system space”)  unrestricted access to hardware  can execute any instruction & reference any memory address.  reserved for the lowest-level, most trusted operating system functions  Ring 3 (user mode)  no ability to directly access hardware or reference memory  must delegate to system APIs CSIT 320 (Blum) 7

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 Somewhat analogous to a dual-boot system, one has different operating system instances in different “partitions.”  However, one partition is the parent of the others – children a.k.a. guest operating systems.  The parent runs the so-called virtualization stack.  And moving from parent to child or child to parent does not require a reboot. CSIT 320 (Blum) 9

 The Parent Partition sits on top of the Hypervisor layer and so is strictly speaking a virtual machine.  It includes the device drivers as well as files for dealing with guest operating systems.  It is the only partition with direct access to the hardware. (Others go through it.) CSIT 320 (Blum) 10

 The Hyper-V Role should be the only server role performed by the Parent Partition.  We are not doing this in lab because I did not want to put you through yet another operating system installation.  Sorry or you’re welcome (depending on your point of view) CSIT 320 (Blum) 11

 Foundation for the partitions  Responsible for keeping partitions separated.  Microsoft tried to keep it as small as possible  so that it would be a very small target for any security threat  so too many systems resources wouldn’t be taken up by the virtualization framework CSIT 320 (Blum) 12

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 The child partitions do not directly access resources instead they communicate requests with the parent partition via the VMBus.  It is the parent that then communicates with hardware. Any response is communicated back to the child through the VMBus. CSIT 320 (Blum) 14

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 The parent partition has the Virtual Service Provider.  The Virtual Service Provider receives the requests through the VMBuses, handles the requests, and sends the responses back to the child partitions via the VMBuses. CSIT 320 (Blum) 16

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 The child partition applications make their requests through the Virtual Service Consumer which passes the request from the child through the VMBus to the Virtual Service Provider on the parent partition.  Consider the bottom of the I/O stack on the child CSIT 320 (Blum) 18

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 The Virtual Machine Management Service is the user-level application that allows a user logged onto the parent partition to administrate the virtual machines.  E.g.  Determine if the virtual machine connect to the DVD/CD drive  Assign to the virtual machine a virtual network adapter CSIT 320 (Blum) 20

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 Each virtual machine has its corresponding “worker process” on the parent partition.  It serves as the child’s representative on the parent partition. CSIT 320 (Blum) 22

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 The concept of virtual device can make each child partition “believe” that it has sole access to a device.  Virtual devices are broken into two categories  Synthetic (enlightened) take advantage of the VMBus and are more responsive  Emulated (legacy or core) often used when virtual machine is modeling an older system with older devices, slow, function in parent partition’s worker process CSIT 320 (Blum) 24

 Windows Server 2008 R2 Hyper-V: Insiders Guide to Microsoft’s Hypervisor, John Kelbley & Mike Sterling, Sybex  ecurity)   download.microsoft.com/download/5/b/9/5b 97017b.../vir047_wh06.ppt CSIT 320 (Blum) 25