Virtualization is a technology that has been gaining a lot of popularity in recent years. Virtualization allows you to host one or more virtual systems, or virtual machines (VMs), on a single physical system. Organizations are using virtualization more and more to reduce costs and sometimes use VMs to host honeypots or honeynets.
Note: This blog is an excerpt from the
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Virtualization and VMs
Different virtual machines can run different operating systems. For example, a VM could be running Microsoft, Linux, UNIX, or just about any other operating system needed by the organization.
Admittedly, you’ll need to beef up the core resources of the physical system, which is also called the host. It needs multiple processors, massive amounts of RAM, more hard drive space, and one or more fast network cards. However, the cost of the hardware for a single system is much less than you’d pay for multiple separate systems. It also requires less electricity, less cooling, and less space.
Several virtualization technologies currently exist, including VMware, Microsoft’s Hyper-V, Window’s Virtual PC (VPC), and Sun’s VirtualBox. VMware has been around the longest as a server product, and it’s specifically designed to host multiple machines in a production environment. Microsoft’s Hyper-V is a direct competitor with VMware.
Microsoft’s VPC and Sun’s VirtualBox are free and run on desktop systems such as Windows 7. You can use them to create simple test environments that include multiple systems within an isolated virtual network. VPC does not support 64-bit operation systems as virtual hosts, but Sun’s VirtualBox does support 64-bit hosts.
It’s worth pointing out that virtual machines are simply files. These files certainly have some complexity, but they are just files. As an example, the following figure shows Microsoft’s Hyper-V Manager running on a Windows Server 2008 R2 system, along with Windows Explorer. In the figure, I’ve selected the Win7 VM in Hyper-V and browsed to the folder holding all of the VM files in Windows Explorer. You can see the Win7 virtual hard disk (VHD) and other folders associated with the VM. It’s relatively easy to export these files from one server and import them to another server.
The figure also shows a Snapshots section in Hyper-V Manager. Administrators can take a snapshot of a system at any time. They can later revert the VM to the exact state it was in when the snapshot was taken.
Reduced Footprint with Virtualization
The amount of physical space IT systems require and the amount of power they consume is sometimes referred to as their footprint. In this context, footprint is referring to an environmental footprint. For example, a carbon footprint refers to the total amount of carbon dioxide emitted due to the consumption of fossil fuels.
If an organization uses fewer physical servers, it reduces its footprint. A reduced footprint results in fewer wasted resources. Additionally, it can improve physical security, since the organization has less physical hardware to protect.
It’s worth noting that many organizations have underutilized servers. For example, a server may be running at less than 10 percent utilization, resulting in a significant amount of wasted resources. Not only is the extra processing power of these servers wasted, but all of the power and air to cool the servers is also wasted. This is one of the main drivers for physical to virtual (p2v) projects. For example, one company I know of did a survey and found that 80 percent of their servers were operating at less than 10 percent utilization. By virtualizing the servers, the company was able to save money on heating, ventilation, and cooling (HVAC) and server equipment.
Compare the deployment of five servers. If an organization installs five virtual servers on a single physical server instead of five, it saves on multiple fronts. The hardware costs less, takes up less space, consumes less power, and requires less cooling.
Similarly, if an organization converts a large datacenter from primarily physical servers to virtual servers, it can significantly reduce its datacenter’s footprint. For example, it may be able to reduce the size of a large datacenter from twenty rows of bays to just four rows.
Virtualization reduces the footprint of an organization’s server room or datacenter and helps eliminate wasted resources. It also helps reduce the amount of physical equipment, reducing overall physical security requirements.
Increased Availability with Virtualization
Virtualization management software has improved over the years. Whether you’re using VMware’s virtualization products or Microsoft’s Hyper-V technology, you have tools that allow you to easily manage multiple physical servers hosting these virtual servers. Overall, this provides increased availability by reducing unplanned downtime for the virtual servers.
As mentioned previously, VMs are files. Just as you can copy a couple of text files from one system to another, you can also copy the VM files from one host to another.
For example, if one of your physical servers becomes overloaded, you can move virtual servers off the overloaded system to another physical server. Some virtual server management software makes this as simple as dragging and dropping the virtual servers from one host to another.
It’s also easy to restore a failed virtual server. If you create a backup of the virtual server files and the original server fails, you simply restore the files. You can measure the amount of time it takes to restore a virtual server in minutes. In contrast, rebuilding a physical server can take hours.
Most virtual management software also supports snapshots. For example, the Figure shown earlier showed that a snapshot was taken of the Win7 VM. This can be very useful when testing updates. You can take a snapshot of a system prior to the update. If the update causes undesired results, you simply restore the snapshot and, as the saying goes, “it’s like it never happened.”
Isolation with Virtualization
Organizations usually configure online virtual servers so that they can communicate with other virtual and physical systems on the network. They use virtual network interface cards (NICs), and virtual networks for connectivity. However, it’s also possible to configure the virtual systems so that they are completely isolated.
For example, you can isolate a virtual server so that it can’t communicate with any other virtual or physical systems. In this way, it works just like a single system without a NIC. You can also group several virtual servers in their own virtual network so that they can communicate with each other but are isolated from hosts on the physical network.
Many security professionals use a virtual system or virtual network to test and investigate malicious software (malware). Malware released in an isolated environment presents minimal risk to the hardware and host operating system. Unfortunately, some malware is able to detect that it is running in a virtual environment. In some cases, malware developers have written code to change the behavior of the malware when it discovers it is running in a virtual environment.
Security professionals use virtual systems to perform research on threats such as viruses. The virtual system remains isolated, preventing risk of contamination to the production environment.
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