Beginning this month, virtualization.info reported that VMware removed the download links to VMware ESX, moving them to another page. With this VMware clearly stated that organizations should move to ESXi, it’s small footprint hypervisor. VMware vSphere 4.1 is the last release to support both het ESX and ESXi hypervisor.
To further support this VMware has released the VMware ESXi 4.1 Operations Guide, the paper which contains 22 pages describes the architecture of VMware ESXi and then explains how various management tasks are performed in it, and the VMware 4.1 ESXi Migration Guide, containing 11 pages providing guidance on how to make the transition to ESXi, along with several recommendations to help ensure a timely and seamless migration. VMware also makes available Migration Checklists and a Host Configuration Worksheet.
The differences in architecture between ESX and ESXi are described as followed:
In the original VMware ESX architecture, the virtualization kernel (VMkernel) is augmented by a management partition known as the console operating system (COS) or service console. The primary purpose of the COS is to provide a management interface with the host. Various VMware management agents are deployed in the COS, along with other infrastructure service agents (for example, name service, time service, logging, and so on). In this architecture, many customers deploy other agents from third parties to provide a particular functionality, such as hardware monitoring and system management. Furthermore, individual administrative users log in to the COS to run configuration and diagnostic commands and scripts.
In the VMware ESXi architecture, the COS has been removed, and all of the VMware agents run directly on the VMkernel. Infrastructure services are provided natively through modules included in the VMkernel. Other authorized third-party modules, such as hardware drivers and hardware monitoring components, can run in the VMkernel as well. Only modules that have been digitally signed by VMware are allowed on the system, creating a tightly locked–down architecture. Preventing arbitrary code from running on the VMware ESXi host greatly improves the security and stability of the system.
The Operations Guide details the differences between ESX and ESXi and how to Operate topics like Management, Automation, Deployment, Systems Management, Authentication and Diagnostics and Troubleshooting.
The Migration Guide details the planning of the Migration by choosing a migration path, defining pre-migration tasks, validate prerequisites and verifying host requirements, the migration and the post-migration tasks.
Thanks to Duncan Epping for providing the links.