Virtual machine host servers are computers which create and deploy computing instances that do not physically exist; rather they are separated from physical hardware through software.
Hypervisors, installed directly onto hardware or through existing operating systems, such as VMware, Microsoft Hyper-V and Citrix XenServer are among many examples of virtualization programs used to simulate physical environments.
1. Scalability
Virtual machines (VMs) allow multiple applications to coexist on one physical server, making use of all available memory and unused capacity more efficiently. Furthermore, their scalability on demand reduces hardware requirements and downtime caused by upgrades or maintenance procedures.
If a virtual machine (VM) becomes overloaded, an intelligent control mechanism can use hypervisor to dynamically initiate more real servers to address load balancing issues in order to ease its burden and save wasteful energy costs. With on-demand scaling available through hypervisors, waste and energy costs can be decreased significantly.
Scalability makes it easier for IT departments to update individual applications without impacting other systems or increasing security risks, and VMs can easily be backed up and restored if data loss occurs; this not only simplifies disaster recovery but reduces downtime as well as increasing return on investment for existing hardware.
2. Isolation
Isolation helps protect host and guest machines from malicious attacks by channeling internet connections between them via virtual machines, similar to routers. By default, virtual machines utilize network modes similar to routers when channeling internet traffic between their guest machines and host machines.
Isolating a virtual machine from its host machine also ensures that files stored on one aren’t transferred to the other and their respective operating systems remain separate – providing an effective means to test applications without fear of their integrity being compromised and potentially impacting other programs.
This isolation can also reduce the likelihood of power peaks affecting performance on one physical server, increasing hardware utilization while saving costs. Azure also offers isolated VM sizes that offer strong hardware encapsulation as well as support for multiple nested virtual machines.
3. Convenience
Virtual machines (VMs) enable organizations to consolidate server infrastructure and reduce IT costs through multiple operating systems running simultaneously on one piece of hardware, resulting in lower IT expenses and greater server consolidation.
Virtual machines (VMs) don’t require an external management console to set up and manage, making them an attractive solution for IT professionals as well as business users alike.
The left panel displays an overview of VM Guest overview and existing hardware installed to a virtual machine (VM). Clicking an item’s arrows allows for editing its hardware settings; to apply these changes click Apply; some changes take immediate effect while others need rebooting in order to take full effect.
4. Security
As with physical servers, virtual servers (VMs) are vulnerable to online attacks. Attackers no longer just target individual desktops and home machines with poor security; now they’re targeting VM hosts with 10 or more guest OSes running securely within tight configurations.
Virtual machines (VMs) isolate hardware layers, but if an attacker gains access to the hypervisor they gain complete control of a computer. A hypervisor acts like an intermediary program between guest system calls and those supported by host OS system calls; compromise of this program grants access to all of its controlled VMs as well as potentially the host OS [Higgins07].
At times, two virtual machines (VMs) communicating can be advantageous – particularly when monitoring another VM or implementing network technologies requiring multiple peers – however this communication can introduce vulnerabilities.
5. Flexibility
As virtual machines (VMs) are hardware independent, it makes migration or relocation between physical servers simpler, while update times are significantly reduced compared to physical servers.
Hypervisor software isolates virtual machines (VMs) from their host hardware and allocates system resources to guest OS. There are two types of hypervisors: type-1 and type-2. Type-1 hypervisors run directly on hardware while type-2 hypervisors work on top of host OS such as Microsoft Hyper-V or Parallels Desktop for Mac.
Virtual machines (VMs) can serve a number of different functions, from accessing software that was intended for another operating system to testing new applications or investigating malware or viruses in a safe and isolated environment. Furthermore, they can create backup images of existing systems for faster disaster recovery.