Database virtualization - the separation of the database layer, which lies between the storage and application layers within the application stack
Network virtualization - creation of a virtualized network addressing space within or across network subnets
Application virtualization - hosting of several applications in an environment independent from the underlying OS
Now that you know a few things regarding virtualization, let us talk about the advantages of using it.
One of the main reasons why virtualization was invented is to save time and money. Virtualization makes it possible to reduce the number of computer hardware, servers and data centers but still caters to various software workloads thus reducing the cost of maintenance, manpower, and energy consumption. Through virtualization, time consuming tasks like monitoring, upgrading, and software configuration can be conveniently and quickly handled. Virtualization is also utilized to provide better security and stability. Like, if one virtual machine is hacked, only that particular VM is compromised while the others are safe and secure. Also, a software bug on one VM will not affect other virtual applications or operating systems. Software developers make use of virtualization by testing their programs across different platforms through virtual machines.
Let us take a look at some of the most popular virtualization software available for Linux:
Linux-VServer is a virtual private server utilization achieved by adding operating system-level virtualization functionalities to the Linux kernel via kernel level isolation. Virtual private servers are typically used in web hosting services, where they are effective in separating customer accounts, pooling resources and housing any possible security breaches. Linux-VServer is able to run multiple virtual units at once, with each unit adequately isolated to guarantee the required security while using resources efficiently.
KVM is a Linux kernel virtualization infrastructure that features native virtualization using Intel VT-x or AMD-V. Paravirtualization support is available for Linux and Windows guests using the VirtIO framework, which includes a paravirtual Ethernet card, a disk I/O controller, a balloon device for adjusting guest memory-usage, and VGA graphics interface using VMware drivers.