VMware ESXi or simply ESXi, is a bare-metal hypervisor developed by VMware, Inc. It is part of VMware's vSphere virtualization suite, designed to efficiently run multiple virtual machines (VMs) on a single physical server.

Here's a breakdown of its key components and functionalities:

1. Bare-Metal Hypervisor:

• ESXi is installed directly on the physical server hardware, without the need for a separate operating system.
• This approach enhances performance and reduces overhead compared to hosted hypervisors, which run on top of a conventional operating system.

2. Virtualization Layer:

• ESXi creates a virtualization layer that abstracts the underlying hardware resources (CPU, memory, storage, and networking), allowing multiple VMs to share the physical resources efficiently.
• It provides tools for managing these virtual resources, such as allocating CPU and memory resources, creating and configuring VMs, and managing storage and networking configurations.

3. Management Interfaces:

• ESXi can be managed through various interfaces, including:
  • vSphere Client: A graphical user interface (GUI) for managing individual ESXi hosts and virtual machines.
  • vSphere Web Client: A web-based interface for accessing vSphere features, including VM provisioning, monitoring, and management.
  • Command-Line Interface (CLI): Allows administrators to perform advanced configuration and management tasks using commands.

4. High Availability and Fault Tolerance:

• ESXi supports features like VMware High Availability (HA) and VMware Fault Tolerance (FT), which enhance the reliability and availability of virtualized workloads.
• HA automatically restarts VMs on other hosts in the event of a host failure, while FT provides continuous availability by maintaining a secondary VM that mirrors the primary VM's execution state.

5. Resource Management:

• ESXi includes features for optimizing resource utilization, such as:
  • Distributed Resource Scheduler (DRS): Automatically balances VM workloads across multiple hosts based on resource utilization and predefined rules.
  • Distributed Power Management (DPM): Dynamically adjusts power consumption by consolidating VMs onto fewer hosts during periods of low demand.

6. Security:

• ESXi includes built-in security features to protect virtualized environments, including:
  • Secure Boot: Ensures that only signed and trusted code runs on the hypervisor.
  • Encrypted vMotion: Secures live migrations of VMs between hosts by encrypting network traffic.
  • Role-Based Access Control (RBAC): Granular control over user permissions and access rights within the vSphere environment.

ESXi is a bare-metal hypervisor developed by VMware for virtualizing server workloads. It enables efficient resource utilization, high availability, and advanced management capabilities, making it a popular choice for organizations looking to consolidate servers, streamline IT operations, and increase flexibility and scalability in their data centers.

Sources:

• VMware ESXi Documentation: VMware ESXi