What is VMware vSphere 4?

TABLE OF CONTENTS
Overview | ESX | ESXi | vSphere and cloud computing
Licensing | Additional resources

VMware vSphere 4  is VMware Inc.'s flagship server virtualization suite and consists of several technologies that provide live migration, disaster recovery protection, power management and automatic resource balancing for data centers.

In this article, you'll learn about the ESX and ESXi versions of VMware vSphere 4, licensing tiers, how vSphere 4 can be used as a platform for private cloud computing and more.

Vsphere is the successor to the VMware Infrastructure 3 (VI3) product line but was rebranded as vSphere 4 with the release of ESX 4.0 hypervisor. As a result, VMware vSphere 4 shares many features with its predecessor, VI3, such as:

• the ability to run vCenter Server (previously known as VirtualCenter)
• VMotion (which enables the live migration of virtual machines [VMs] from one host to another without shutting down a migrating VM);
• High Availability (which restarts VMs on another physical host in the event of failure and reduces downtime); and
• Distributed Resource Scheduler (or DRS, which dynamically allocates resources to high-priority applications).

The ESX 4 suite builds on the VMware Infrastructure foundation with stability, availability and security improvements. Key vSphere technologies include:

• vShield Zones;
• thin provisioning; and
• host profiles.

The vSphere 4 platform is also the backbone of the VMware View desktop virtualization infrastructure. View-based virtual desktops are actually virtual machines hosted by vSphere hosts. As such, View users can access vSphere technologies such as VMotion and DRS.

From a server virtualization standpoint, VMware vSphere 4 comes in two hypervisor flavors: ESX and ESXi.

The ESX architecture consists mainly of the service console, which runs on VMware's VMkernel hypervisor code.

Measuring approximately 8 GB, the service console is a privileged VM that runs an optimized version of Red Hat Linux OS. It contains drivers, services, processes and utilities for VMkernel management.

User can log in to the service console though a secure shell client to run scripts, view logs and install applications. It also serves as a hub to troubleshoot virtual environment problems.

Ultimately, ESX has a limited future compared with ESXi, and VMware itself has stated that it views ESXi as its next generation hypervisor. One key question that remains is, when will VMware stop offering ESX?

Both the ESX and ESXi hypervisors share the same VMkernel code, but ESXi sheds the hefty service console in favor of a rudimentary management console. This replacement reduces ESXi's size to approximately 60 MB -- less than 1% of ESX'size. The smaller footprint allows ESXi to boot from a removable storage media, such as USB flash drives -- unlike ESX, which requires dedicated drives to run the service console and hypervisor.

Because of its smaller footprint, ESXi is easier to install and manage. The ESXi management console is a basic remote interface that supports few commands; engineers chose to rely on remote management tools such as vSphere Command-Line Interface and vCenter for the bulk of ESXi's administration. Also, the ESXi patching process is simpler because there are no patch dependencies or install orders.

Additionally, VMware states that ESXi is more secure than ESX. For example, there is one less attack vector for hackers because ESXi lacks a privileged VM running a Linux OS.

Nevertheless, users have been slow to adopt ESXi. There are several possible reasons for slow uptake:

• ESX users are reluctant to forfeit the service console.
• ESXi lacks key ESX management features, such as:
• • booting from a storage area network;
  • a Web management interface; and
  • support for network jumbo frames, scriptable installations and Active Directory integration.

Until these issues are addressed, or the ESX support ends, VMware may see slow migration rates from ESX to ESXi.

Cloud computing's core is built on several virtual server infrastructure principles, such as scalability and resource management. In virtual environments, the ease of provisioning VMs and applications provides administrators a level of flexibility that is unattainable in a traditional server infrastructure. But IT professionals are still limited by a virtual environment's physical resources.

In a public or hybrid cloud computing environment, however, administrators can shift virtualization applications to the cloud, where service providers are responsible for allocating the necessary resources.

With the announcement of VMforce -- a joint partnership between VMware and Saleforce.com -- VMware vSphere 4's functionality has expanded to public, private and hybrid clouds. The vSphere 4 platform along with the SpringSource tc Server architecture will provide the foundation for these cloud services, while Saleforce.com will manage the application delivery mechanism for public and hybrid cloud environments.

For IT professionals, the VMforce service promises the familiarity of VMware vSphere 4 without the responsibility of managing the server infrastructure's resource load.

If you prefer other public cloud infrastructures, the VMware vCloud and vCloud Express tools allow users to migrate workloads from VMware hypervisors to third-party public cloud providers that support the vCloud API.

VMware vSphere 4 is also used for private cloud implementations. It has the ability to tie in all the necessary technologies -- such as servers, storage, networking equipment, virtualization software and operating systems -- with cloud computing management components like chargeback reporting, automation and self-service.

VMware vSphere 4 offers an assortment of licensing tiers to fit small, medium-sized and large enterprise structures. For small businesses, VMware offers the following pricing plans:

• Essentials
• Essentials for Retail and Branch Offices
• Essentials Plus
• Essentials Plus for Retail and Branch Offices

Medium-sized and enterprise companies have even more licensing options:

• Essentials for Retail and Branch Offices
• Essentials Plus for Retail and Branch Offices
• Standard
• Advanced
• Enterprise
• Enterprise Plus

For a more in-depth description of each licensing bundle, visit VMware's vSphere editions comparison page.

For more information about VMware vSphere 4, check out the following resources:

• VMware vSphere beginner's guide
• The 'plus' in vSphere 4.0 Enterprise Plus licensing: Percolating thoughts
• VMware vSphere: Got 64-bit hardware?
• The best VMware product guide: Hypervisors, desktop products and cloud services
• The best guide to VMware's management products
• VMware's vSphere 4 official product page
• What's new in VMware vSphere 4
• VMware's official take on cloud computing