Esx

ESX is VMware’s bare-metal hypervisor that forms the core of the VMware vSphere virtualization platform. Installed directly on server hardware, it enables multiple virtual machines to run on a single physical host by sharing CPU, memory, storage, and network resources. ESX provides the virtualization layer (the VMkernel) and access to storage through VMFS, allowing efficient consolidation of workloads.

Historically, ESX originated as ESX Server and evolved into two tracks: ESX and ESXi. The earlier ESX line combined the hypervisor with a Service Console, a small Linux-based management OS. VMware later introduced ESXi, a lean, purpose-built microkernel hypervisor with no Service Console, which reduced footprint and attack surface. Today ESXi is the standard offering, and ESX is largely treated as legacy in modern deployments, with VMware continuing to support current vSphere environments that may still include ESX in some instances.

Management and features are provided through the broader vSphere stack. ESX hosts are managed with vCenter Server, and virtual infrastructure is configured via the vSphere Client. Key capabilities include dynamic resource management, High Availability (HA) for automatic VM restart after host failure, vMotion for live migration of running VMs between hosts, Storage vMotion for migrating VM disks without downtime, and Fault Tolerance for continuous VM operation. Distributed Resource Scheduler (DRS) helps balance compute resources across a cluster, and storage-related features integrate with VMware storage solutions such as VMFS and, in modern setups, vSAN.

Hardware and licensing considerations follow VMware’s guidelines. ESX/ESXi require x86-64 hardware with hardware-assisted virtualization (such as Intel VT-x or AMD-V) and compatible storage devices; compatibility is verified via the VMware Compatibility Guide. In current VMware offerings, ESXi is the primary hypervisor, with ESX mostly phased out in new deployments.