VMware ESXi Server

VMware ESXi Server is computer virtualization software developed by VMware Inc. The ESXi Server is an advanced, smaller-footprint version of the VMware ESX Server, VMware's enterprise-level computer virtualization software product. Implemented within the VMware Infrastructure, ESXi can be used to facilitate centralized management for enterprise desktops and data center applications.

VMware Inc. developed ESX and ESXi as bare metal embedded hypervisors, which means that they run directly on server hardware and do not require the installation of an additional underlying operating system. This virtualization software creates and runs its own kernel, which is run after a Linux kernel bootstraps the hardware. The resulting service is a microkernel, which has three interfaces:

• Hardware
• Guest system
• Console operating system (service console)

Some of the distinct features of VMware ESXi Server are:

• The ESX architecture uses a service console for management tasks, including script execution and third-party agent installation. ESXi does not have this service console, which significantly reduces the hypervisor code-base footprint. By removing the service console, ESXi migrates the management functionality from a local command line interface to remote management tools.
• ESXi's application programming interface-based partner integration model removes the requirement to install and control third-party management agents. This helps to automate routine tasks by using remote command line scripting environments, which include vCLI or PowerCLI.
• ESXi includes an ultra-thin architecture, which is not dependent on a general-purpose operating system; however, it continues to deliver all the performance and functionality offered by VMware ESX. VMware ESXi is highly reliable because its smaller code-base presents a lesser attack area with less code to patch.
• Due to its thinner architecture, the installation happens in just 10 minutes, with the server booting up in two to three minutes. Also, ESXi can be installed easily and booted even from a USB flash drive. ESXi Server is sold as a built-in hypervisor, which eliminates the need to install the ESXi Server on the hard drive.
• ESXi Server has a simple security profile configuration when compared to ESX Server.
• ESXi uses a small direct console user interface instead of a full server console.
• Because of its more compact size and reduced number of components, ESXi needs considerably fewer patches when compared to ESX. This helps to shorten service windows and reduce security vulnerabilities.