How to Manage Server Virtualization in Windows Server 2012
Written by: Ed Baker, Firebrand Training
What is Server Virtualisation?
You may have noticed that the IT world has become a very cloudy place indeed recently. The reason that such strategies can work both publicly and privately is the advent of Server Virtualization. The ability to run ‘virtual’ servers – or software computers – within a single physical hardware-based computer.
This is enabled by clever hardware virtualization technology, and the creation of an entity called a hypervisor – a piece of software that sits between the hardware and the virtual machines. This hypervisor shares out the hardware resources such as CPU, RAM and Network access, whilst keeping all the machines separate. A very clever piece of work. Microsoft has one of the leading products which is called Hyper-V.
Now that Windows Server 2012 and Windows 8 have been released, Hyper-V is available for the first time in three distinctly different versions. Hyper-V on the client (Windows 8), on the server (Windows Server 2012) and as the server (Windows Hyper-V Server 2012). The last of these is entirely free and is based on the non-GUI Windows Server 2012 Core but is only able to run the Hyper-V role.
The major difference between the full Windows Server version and the Client and Hyper-V server is that NO virtualization licences are provided. Windows Server Standard allows two extra licences for virtualized machines whereas the datacentre edition allows unlimited versions.
What exactly is Hyper-V and how do you use it?
Hyper-V is one of Windows Server 2012’s 18 roles. It can be installed using Server Manager or PowerShell 3.0 (and DISM an imaging tool). Once installed, the server becomes known as a Hyper-V host, and any Virtual machines installed as Hyper-V guests (some call this a Parent / Child relationship).
If the Hyper-V role is installed or the local server manages a remote server with it installed, then the Hyper V group appears in Server Manager.
This allows the administrator to see events, services, best practices, performance and other statistics related to the Hyper-V servers managed by this computer.
To manage Virtual Machines (VMs), a simple right-click on the server or click tool and Hyper-V manager. The Manager can also be run from PowerShell, the start screen or in a simple CMD window, all very flexible.
The Hyper-V Manager can connect to several other Hosts, or simply manage the single host. Microsoft recommends the System Center Virtual Machine Manager to manage multiple Hyper-V hosts.While this is expensive, it does add a huge level of functionality and flexibility to your VM management.
The Hyper-V manager window allows complete control as indicated below.
If you choose to use your VMs as clustered guests, then you manage those from the Failover Cluster Manager instead.
The VM Properties window has four tabs which show the networking settings (MAC Address etc) memory allocation and also, if Hyper-V replication has been enabled on the VM, the state of replication and whether the VM is the primary or replica.
Snapshots are a point in time image of the changes made to the VM. These are an excellent way to test and manage training and other solutions, but are not recommended for production workloads. It is possible to take a snapshot at various stages of an implementation, and to revert to any snapshot at any time.
In Windows Server 2012, for the first time it is possible to snapshot and clone VM Domain Controllers without any dramatic or catastrophic effects.
The Host has a number of settings including a completely new (for Server 2012) Virtual Switch which is extensible to allow Cisco (for example) to produce a software version of a leading hardware switch, for compatibility. The Host Settings are shown below.
Each VM has a number of unique settings to control its functions, behaviour and content. Importantly, the integration features dictate how the VM interacts with the Host Server.
To create virtual networks there are three choices…
- External -must be bound to a physical network adaptor and can communicate on the main LAN. Only one external network can be bound to a physical card at any one time.
- Internal – allows the VMs and the Host to communicate on the network but not externally on the main LAN.
- Private – allows inter-VM communication but no communication with the host.
The Virtual Switch is also completely VLAN aware so VMs on different Hosts can communicate through VLAN tagging. The management VLAN is also configurable per switch.
In addition, the SR-IOV feature allows the Switch to communicate directly with a suitable enable NIC and removes the Host from the workload, this dramatically increases throughput.
MAC Addresses can be allocated to VMs manually or dynamically if required.
What Else is new?
There are a whole load of new and exciting features in Hyper-V, including:
Resource Metering – You can now track and gather data about physical processor, memory, storage, and network usage by specific virtual machines. This allows multiple tenants to be charged on actual usage of machines.
Dynamic Memory (Smart Paging) – This allows a machine to startup even if there is not enough system RAM in the host.
Live migration can now be performed in non-clustered systems AND more than one at a time can be configured.
New VHDX format for Virtual Hard Disks, brings space and speed enhancements as well as huge VHD sizes of up to 64 Terabytes.
Importing a VM that has not been exported is now possible.
Hyper-V replica allows a hot spare to be kept across a high latency WAN, there would be down time but not much if you needed to failover to the replica version.
In fact there are so many new features, this article cannot cover them all. Head off to Microsoft TechNet to see them all.
I recommend downloading the evaluation, installing the server, adding the role and running the NEW VM wizard to find out more. Remember, most modern operating systems are fully supported And even if they aren’t, it is still possible to run them – the support only refers to the host integration tools. Once you have installed a couple of VMs, why not connect them by internal virtual network and get some testing going?
Ed Baker is an MCT specializing in Windows Server and Client products with 20 years industry experience. Ed teaches for Firebrand Training and the Firebrand Microsoft IT academy Programme in the UK. @edbaker1965 holds three of the new MCSE certifications as of November 2012.