In practice, it is important to understand the concepts and applications of virtualization technology, even though you may not have come into direct contact with it yet. For experimental environments, we usually use a product like VMware Workstation, which is suitable for testing and personal use. However, when it comes to enterprise-level virtualization needs, a more specialized solution – VMware vSphere – is required.
Dynamic Resource Control and High Availability
Dynamic Resource Control: Allows the system to automatically adjust the resources allocated to virtual machines as needed.
High Availability (HA): Ensures that virtual machines can be quickly brought back up and running in the event of a hardware failure.
Understanding ESX and ESXi
ESX and ESXi are both virtualization platforms provided by VMware that are installed on physical servers, run as operating systems, and support the creation of multiple virtual machines. The main difference between the two is that:
ESX includes a service console, which is a Linux kernel-based management interface.
ESXi is a lighter, more secure version that removes the service console and manages and schedules hardware resources directly from the VMkernel.
Beginning with vSphere 4.1, VMware has discontinued updates and support for ESX in favor of focusing on ESXi.
Key Components of ESX/ESXi
Service Control: present in ESX, provides a command line interface to manage the VMkernel.
VMkernel: Responsible for hardware management and resource scheduling, present in both ESX and ESXi.
vSMP Technical Introduction
vSMP or VMware Virtual Symmetric Multi-Processing allows multiple virtual CPUs to be configured for virtual machines to increase computing power.
vCenter Server
vCenter Server is the core tool used to centrally manage multiple ESXi hosts and the virtual machines on them. vCenter Server provides a number of advanced features, including but not limited to:
1. Virtual Machine Templates: rapid deployment of new virtual machines.
2. Role Access Control: Refine user permissions for secure management.
3. Resource Management Control: Flexibly allocate CPU, memory and other resources to each VM.
4. Online Migration: Realizes non-disruptive virtual machine migration through vMotion. 5.
5. Dynamic Resource Allocation: Intelligent load balancing between different hosts. 6.
6. High Availability: Automatically restarts VMs that are down due to failures. 7.
7. Fault Tolerance: Keeps VM configurations synchronized to ensure business continuity.
8. EVC (Enhanced vMotion Compatibility): Solves compatibility issues when migrating across different hardware.
9. Host Profile: Simplifies the process of configuring new hosts.
10. Distributed Virtual Switch: Unifies management of network settings for increased flexibility.
These features require vCenter Server and corresponding storage network support to be realized.
Other Important Features
vCenter Update Manager: Centralized management and automated updates for ESXi hosts and virtual machines.
Virtual Firewall: Enhances network security.
Antivirus integration: Virus protection at the ESXi level to protect all virtual machines.
In summary, VMware vSphere provides a complete virtualization solution that meets the needs of everything from simple lab environments to complex enterprise data centers.