The Virtualization of the operating system is the use of code to allow computer hardware to run multiple instances of different operating systems.
Concurrently permits you to run various applications requiring different systems on one computer system.
It is also known as OS-level virtualization. It is a virtualization technology that works on the OS layer. In this, the kernel of an OS allows more than one isolated user-space instance to exist. such instances are known as container/software or virtualization engines. In other words, the OS kernel will run on a single system and offer that operating system’s functionality to copy on each of the isolated partitions.
Uses of OS Virtualization
- It is used for the virtual hosting environment.
- Used in securely allocation of finite hardware resources among a large number of different users.
- System administration users it to consolidate server hardware by moving services on separate hosts.
- To improvised security by separating various applications to various containers.
- These types of virtualization don’t need hardware to work efficiently.
How OS Virtualization Works
The steps for how virtualization works are given below;
- Connect to OS virtualization.
- Connect to the virtual disk.
- Then connect this disk to the client.
- OS is streamed to the client.
- In further addition, streaming is required; it is done.
1) Connecting to the OS Virtualization server:
First we start the machine and set up the connection with the OS Virtualization server. Most of the products offer several possible methods to connect with the server. One of the most popular and used methods is using a PXE service, but also a boot strap is used a lot (because of the disadvantages of the PXE service). Although each method initializes the network interface card (NIC), receiving a (DHCP-based) IP address and a connection to the server.
2) Connecting the Virtual Disk:
When the connection is established between the client and the server, the server will look into its database for checking the client is known or unknown and which virtual disk is assigned to the client. When more than one virtual disk are connected then a boot menu will be displayed on the client side. If only one disk is assigned, that disk will be connected to the client which is mentioned in step number 3.
3) VDisk connected to the client:
After the desired virtual disk is selected by the client, that virtual disk is connected through the OS Virtualization server . At the back-end, the OS Virtualization server makes sure that the client will be unique (for example computer name and identifier) within the infrastructure.
4) OS is “streamed” to the client:
As soon the disk is connected the server starts streaming the content of the virtual disk. The software knows which parts are necessary for starting the operating system smoothly, so that these parts are streamed first. The information streamed in the system should be stored somewhere (i.e. cached). Most products offer several ways to cache that information. For examples on the client hard disk or on the disk of the OS Virtualization server.
5) Additional Streaming:
After that the first part is streamed then the operating system will start to run as expected. Additional virtual disk data will be streamed when required for running or starting a function called by the user (for example starting an application available within the virtual disk).
Advantages of OS Virtualization
- OS virtualization usually inflicts little or no overhead.
- OS virtualization can live migration.
- OS virtualization can also use dynamic load balancing of the container between nodes and a cluster.
- The file-slevel copy-on-write (COW) mechanism is possible on OS virtualization, which makes facile to backup files, more space-efficient and easy to cache than the block-level-copy-on-write schemes.