Type 1 and Type 2 Hypervisor

Hypervisor is mainly classified into two

Type 1/Native/Bare Metal Hypervisor
Type 2/Hosted Hypervisor

Type 1 Hypervisor

• This is also known as Bare Metal or Embedded or Native Hypervisor.
• It works directly on the hardware of the host and can monitor operating systems that run above the hypervisor.
• It is completely independent from the Operating System. 
• The hypervisor is small as its main task is sharing and managing hardware resources between different operating systems.
• A major advantage is that any problems in one virtual machine or guest operating system do not affect the other guest operating systems running on the hypervisor.

Examples:

VMware ESXi Server,

 Microsoft Hyper-V,

Citrix/Xen Server,

Type 2 Hypervisor

• This is also known as Hosted Hypervisor.
• In this case, the hypervisor is installed on an operating system and then supports other operating systems above it.
• It is completely dependent on host Operating System for its operations
• While having a base operating system allows better specification of policies, any problems in the base operating system a ffects the entire system as well even if the hypervisor running above the base OS is secure.

  Examples:

VMware Workstation,

Microsoft Virtual PC,

Oracle Virtual Box,

        







         

 

What is the difference between VMware ESX and VMware ESXi?

VMware ESX and VMware ESXi are both bare-metal hypervisors that install directly on the server hardware. Both provide industry-leading performance and scalability; the differenceresides in the architecture and the operational management of  VMware ESXi. VMware ESX relies on a Linux operating system, called the service console, to perform some management functions including executing scripts and installing third-party agents for hardware monitoring, backup or systems management. The service console has been removed from VMware ESXi, dramatically reducing its footprint. By removing the service console, VMware ESXi completes an ongoing trend of migrating management functionality from this local command-line interface to remote management tools.
The functionally of the service console is replaced by remote command-line interfaces and adherence to system management standards.

In the original VMware ESX architecture, the virtualization kernel (VMkernel) is augmented by a management partition known as the console operating system (COS) or service console. The primary purpose of the COS is to provide a management interface with the host. Various VMware management agents are deployed in the COS, along with other infrastructure service agents (for example, name service, time service, logging, and so on). In this architecture, many customers deploy other agents from third parties to provide a particular functionality, such as hardware monitoring and system management. Furthermore, individual administrative users log in to the COS to run configuration and diagnostic commands and scripts.

In the VMware ESXi architecture, the COS has been removed, and all of the VMware agents run directly on the VMkernel. Infrastructure services are provided natively through modules included in the VMkernel. Other authorized third-party modules, such as hardware drivers and hardware monitoring components, can run in the VMkernel as well. Only modules that have been digitally signed by VMware are allowed on the system, creating a tightly locked–down architecture. Preventing arbitrary code from running on the VMware ESXi host greatly improves the security and stability of the system.

How Do VMware ESX and VMware ESXi Work?

VMware ESX and VMware ESXi install directly on the server hardware, inserting a robust virtualization layer between the hardware and the operating system. VMware ESX and ESXi partition a physical server into multiple secure and portable virtual machines that can run side by side on the same physical server. Each virtual machine represents a complete system—with processors, memory,networking, storage and BIOS—so that an operating system and software applications can be installed and run in the virtual machine without any modification. Virtual machines are also completely isolated from each other by the virtualization layer, thus preventing a crash or configuration error in one virtual machine from affecting the others. Sharing the physical server resources among a number of virtual machines increases hardware utilization and dramatically decreases capital costs. The bare-metal architecture gives VMware ESX and ESXi complete control over the server resources allocated to each virtual machine and provides for near-native virtual machine performance and enterprise-class scalability. VMware ESX and ESXi provide virtual machines with built-in high availability, resource management and security features to deliver improved service levels to software applications than static physical environments.

What are VMware ESX and VMware ESXi?

VMware ESX and VMware ESXi provide the foundation for building a reliable and dynamic IT infrastructure. These market- leading, production-proven hypervisors abstract processor, memory, storage and networking resources into multiple virtual machines that each can run an unmodified operating system and applications. VMware ESX and ESXi are the most widely deployed hypervisors, delivering the highest levels of reliability and performance to companies of all sizes.
VMware ESXi is the latest hypervisor architecture from VMware. It has an ultra-thin architecture with no reliance on a general- purpose OS, yet still offers all the same functionality and performance of VMware ESX. VMware ESXi sets a new bar for security and reliability because its smaller code base represents a smaller “attack surface” with less code to patch. This small footprint and hardware-like reliability also enable VMware ESXi to be built directly into industry standard x86 servers from leading server manufacturers such as Dell, IBM, HP, and Fujitsu- Siemens. VMware ESXi was designed with simplicity in mind. Its menu-driven startup and automatic configurations make it the easiest way to get started with VMware virtualization.

Top Virtualization Technology Companies

Virtualization technology is all the rage, but which product is right for your organization? Learn the virtualization vendors that deliver the best software solutions.
You might not require every bit and byte of programming they're composed of, but you'll rejoice at the components of their feature sets when you need them. These solutions scale from a few virtual machines that host a handful of Web sites, virtual desktops or intranet services all the way up to tens of thousands of virtual machines serving millions of Internet users. Virtualization and related cloud services account for an estimated 40 percent of all hosted services. If you don't know all the names on this list, it's time for an introduction.

 

1. VMware

Find a major data center anywhere in the world that doesn't use VMware, and then pat yourself on the back because you've found one of the few. VMware dominates the server virtualization market. Its domination doesn't stop with its commercial product, vSphere. VMware also dominates the desktop-level virtualization market and perhaps even the free server virtualization market with its VMware Server product. VMware remains in the dominant spot due to its innovations, strategic partnerships and rock-solid products.

 

2. Citrix

Citrix was once the lone wolf of application virtualization, but now it also owns the world's most-used cloud vendor software: Xen (the basis for its commercial XenServer). Amazon uses Xen for its Elastic Compute Cloud (EC2) services. So do Rackspace, Carpathia, SoftLayer and 1and1 for their cloud offerings. On the corporate side, you're in good company with Bechtel, SAP and TESCO.

 

3. Oracle

If Oracle's world domination of the enterprise database server market doesn't impress you, its acquisition of Sun Microsystems now makes it an impressive virtualization player. Additionally, Oracle owns an operating system (Sun Solaris), multiple virtualization software solutions (Solaris Zones, LDoms and xVM) and server hardware (SPARC). What happens when you pit an unstoppable force (Oracle) against an immovable object (the Data Center)? You get the Oracle-centered Data Center.

4. Microsoft

Microsoft came up with the only non-Linux hypervisor, Hyper-V, to compete in a tight server virtualization market that VMware currently dominates. Not easily outdone in the data center space, Microsoft offers attractive licensing for its Hyper-V product and the operating systems that live on it. For all Microsoft shops, Hyper-V is a competitive solution. And, for those who have used Microsoft's Virtual PC product, virtual machines migrate to Hyper-V quite nicely.

 

5. Red Hat

For the past 15 years, everyone has recognized Red Hat as an industry leader and open source champion. Hailed as the most successful open source company, Red Hat entered the world of virtualization in 2008 when it purchased Qumranet and with it, its own virtual solution: KVM and SPICE (Simple Protocol for Independent Computing Environment). Red Hat released the SPICE protocol as open source in December 2009.

 

6. Amazon

Amazon's Elastic Compute Cloud (EC2) is the industry standard virtualization platform. Ubuntu's Cloud Server supports seamless integration with Amazon's EC2 services. EngineYard's Ruby application services leverage Amazon's cloud as well.

 

7. Google

When you think of Google, virtualization might not make the top of the list of things that come to mind, but its Google Apps, AppEngine and extensive Business Services list demonstrates how it has embraced cloud-oriented services.

8. Virtual Bridges

Virtual Bridges is the company that invented what's now known as virtual desktop infrastructure or VDI. Its VERDE product allows companies to deploy Windows and Linux Desktops from any 32-bit or 64-bit Linux server infrastructure running kernel 2.6 or above. To learn more about this Desktop-as-a-Managed Service, download the VERDE whitepaper.
 

9. Proxmox

Proxmox is a free, open source server virtualization product with a unique twist: It provides two virtualization solutions. It provides a full virtualization solution with Kernel-based Virtual Machine (KVM) and a container-based solution, OpenVZ.
 

10. Parallels

Parallels uses its open source OpenVZ project, mentioned above, for its commercial hosting product for Linux virtual private servers. High density and low cost are the two keywords you'll hear when experiencing a Parallels-based hosting solution. These are the two main reasons why the world's largest hosting companies choose Parallels. But, the innovation doesn't stop at Linux containerized virtual hosting. Parallels has also developed a containerized Windows platform to maximize the number of Windows hosts for a given amount of hardware.

11. Nutanix

The Nutanix solution consists of the "Nutanix Virtual Computing Platform" which delivers enterprise compute and storage through the deployment of commodity computing servers (called nodes) which each run a standard hypervisor and the Nutanix Operating System (NOS). Each server contains Intel processors, memory, solid-state drives and traditional hard drives, and when added into a cluster aggregates storage resources into a single storage pool. Capacity is added by adding a node to the computing cluster.

What is Virtualization?

Traditionally, operating systems and software run on a physical computer. Several challenges exist
to running a large number of physical servers in a datacenter. The model is not flexible and can be
inefficient. The planning and cost of proper infrastructure (square footage, rack space, power,
cooling, cabling, and server provisioning) are but a few of the problems that IT staff must address.
Typically, a 1:1 relationship exists between a physical computer and the software that it runs. This
relationship leaves most computers vastly underused, leaving between only 5–10 percent of physical
server capacity in use. The cost of the space and power required to house, run and keep these
systems cool can be expensive.

Provisioning physical servers is a time consuming process. In nonvirtualized environments time
must be allotted to procure new hardware, place it in the datacenter, install an operating system,
patch the operating system and install and configure the required applications can take weeks. This
process also includes a myriad of other tasks to integrate the system into the infrastructure. For
example, configuring firewall rules, enabling switch ports and provisioning storage.

Virtualization enables you to run more workloads on a single server by consolidating the
environment so that your applications run on virtual machines. Converting to a virtualized
datacenter reduces the required datacenter square footage, rack space, power, cooling, cabling,
storage and network components by reducing the sheer number of physical machines.
The reduction of physical machines can be realized by converting physical machines to virtual
machines and consolidating the converted machines onto a single host.
Using virtualization technology also changes the way servers are provisioned. You do not need to
wait for the hardware to be procured or cabling to be installed. Virtual machine provisioning is
performed using an intuitive graphical user interface. In contrast to the long process of deploying
physical servers, deploying virtual machines can be deployed in a matter of minutes.