What is VMware ESXi?

VMware ESXi is a type 1 (bare metal) hypervisor installed directly on a physical server, operating without a separate OS. It’s based on the VMkernel, making it lightweight compared to other hypervisors. Administered via vSphere, ESXi was launched in 2001 and is still in use. ESXi stands for “Elastic Sky X integrated.”

What are hypervisors?
Hypervisors act as a bridge between virtual machines and physical hardware, managing resources and ensuring multiple VMs run smoothly on one system. They come in two types: type 1 (like ESXi), which run directly on hardware, and type 2, which run on top of an existing OS.

What is the difference between ESXi and ESX?
ESX, the predecessor to ESXi, was also a type 1 hypervisor but included a service console, making it larger and more storage-intensive. It was phased out with vSphere 5.0 in favor of the more efficient and easier-to-install ESXi.

What is ESXi used for?
ESXi is widely used for server virtualization, offering strong performance, easy scalability, and secure operation across multiple machines. It’s ideal for partitioning resources and creating isolated or temporary test environments.

What are the advantages of ESXi?
ESXi offers several advantages over its predecessor ESX, including lower memory usage, faster installation, and greater flexibility. It enables efficient virtualization of entire data centers, saving money, space, and resources without sacrificing performance or security. With centralized management, easy export of virtual systems, and strong scalability, ESXi makes optimal use of hardware.
Renting an ESXi server can further reduce costs.

Credit : https://www.ionos.com/digitalguide/server/know-how/esxi/