ATOL: VMware virtualization portfolio

23.4.2009 22:31 | Přečteno: 1152× | Linux

Author: Jakub Talaš
Virtualization is one of the most promising and developing IT techniques nowadays. Although virtualization concepts started to appear back in 1960s, the boom of operating systems virtualization began to spread among IT professionals since the dawn of new millennium. VMware is company, that offers widespread virtualization portfolio, from lightweight home toys to hi-end enterprise-class implementations in datacenters. Host operating systems can be Linux, Windows, *BSD and Intel-based Macs. Guests can be virtually everything suitable to run on IA32 and x32_64bit architectures. Most of the products are proprietary and commercial, but VMware is quite Linux-friendly firm, they are also member of Linux Foundation since 2008.

Desktop solutions

First VMware product ever stated was VMware Workstation in 1999. Nowadays it supports advanced features like 3D acceleration, snapshosts taking, transparent support for USB devices and so on. Unity mode also offers guest OS's windows to run separately in seamless mode in host desktop environment. On the other side of spectrum is Vmware Player. It isn't able to create new virtual machines (VM), but can be used for executing VMs created in other VMware's products. In the world of Apple, VMware Fusion is used for virtualizing other operating systems. Competitors on Mac OS are Parallels' virtualization products. VMware ThinApp is new solution for enabling Windows application to run in “sanbox” environment. This prevent for example compatibility issues. Unfortunatelly, this is Microsoft Windows-only software.

Server solutions

In the world of servers is crucial support of high end techologies such as iSCSI, Fibre Channel, Storage area networks. VMware company has server products that are able to ensure compatibility with whole this company's network and storage infrastructure. VMware Server (originally released as GSX Server) is on Linux able to run without X Window system, so you can spare memory for your VMs. In version 2, it brings much better cooperation with VMware Infrastructure, but isn't suitable as replacement of VMware Workstation for home or small office anymore. You can obtain free serial number after registration. Administration is provided easily via web browser with plugin for connecting to VM's desktops. VMware Server doesn't provide such functionality as Workstation – for example allows only one snapshost per VM and 3D acceleration is not supported at all. Flagship of VMware's server virtualization software is ESX server. It is based on RHEL, but is strongly modified; ESX is meant to run in datacenters/big enterprise on certified hardware. Since it doesn't use any host OS (“bare metal”), hardware certification ensures, that ESX will be able to run on your machines. All management services are maintained by Service console (“vmnix” service) over CLI as well as web interface or VMware Console (this console uses slightly modified VNC protocol for remote desktop management).

VMware Infrastructure

Package of ESX server and other extra features is called VMware Infrastructure. It enhances ESX with several high end possibilities

• VMware vCenter Server – provides management and monitoring, instance clonning of VMs, dynamic allocation of resources
• Virtual SMP – virtualization of symetric multiprocessor environment
• VMotion – ensures live migration has no impact to end users. Not even one ping packet doesn't need be lost. Supports migration across any supported hardware. You can migrate more VMs at same time divided to priority classes.
• VMware high availability – provides failover protection. When physical server running ESX crashes, it moves virtual machines to other servers in defined pool.
• VMware vCenter Converter – enables you to convert your real operating system to virtual machine.

VMware Infrastructure also consists of other extras such as tools for consolidated backup or distributed resource scheduling and so on.

Other products

I have come through the most important and most visible software products of VMware, but this company also issues and develops more interesting tools:

• Networking Virtual Infrastructure – developed in cooperation with Cisco Systems. It resides on the top of ESX server and integrates with the hypervisor to virtualize whole VM-aware switching. Example of this is Cisco Nexus 1000V switch.
• ESXi – original purpose for this lightweight hypervisor was to be embedded into new servers as basic virtualization host. It is only 32 MB big (full ESX has 2 GB), so it is very flexible and versatile. ESXi was freed as open source.
• VMware Tools – this utility is open sourced. VMware Tools are in charge of communication between host and guest operating systems taking care of copy&pase, time synchronization etc. Since it was released as open source, VMware tools are now appearing just in Linux distributions – it isn't necessary to install and compile kernel modules to achieve their functionality anymore.
• VMware vSphere 4 – shiny new product, first operating system in the world purposed into cloud environment.

Competitor: Citrix XenServer

Citrix XenServer (that is free) with combination with Citrix Essentials (commercial advanced automation and management for the virtual datacenters) is probably biggest ESX server competitor in the world of Linux-based virtualization.

XenServer serves with lower price than ESX server or VMware infrastructure, so it aims to lower cost solutions (for example allows also 1 CPU licences in opposite to at least 2 CPU licences of VMware). It also has better license policy – array of pricing and configuration options for ESX is quite confusing and complicated.

According to material on the vmware.com, VMware ESX has approximately twice lower slowdown to native. It also wins in most tests (integer as well as floating point math, Xen was little better in encryption or compression tests). On the other hand, since aquiring XenSource by Citrix recently, Xen boosted its performance and continues to get better and better.

Advantages of ESX: Widest selection of guest operating systems, hundreds of prebuilt appliances, de-facto standard.

Advantages of Xen: Open source solution, that doesn't require host OS. Lower cost when compared to VMware Infrastructure.

Disadvantages of ESX: Confusing array of pricing and configuration options.

Disadvantages of Xen: Limited support for MS Windows guests.

Interesting links:

• http://vmware.com/solutions/
• http://www.ics.muni.cz/zpravodaj/articles/540.html
• http://it20.info/blogs/main/archive/2007/06/17/25.aspx
• http://dsumsky.blogspot.com/2008/08/technical-differences-between-vmware.html

       

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Komentáře

[marekb]

VMware virtualization and ESX server is not based on RHEL ! It has it's own kernel called VMkernel, which is 100% percent proprietary. VMkernel runs directly on a hardware as a hypervizor, and there is one special Virtual Machine pre-installed on each ESX server - running on top of this hypervizor. This VM is called Service Console and has special priviledges to manage the hypervizor - inside this VM runs modified version of RHEL - but once again, VMkernel is not based on Linux, the service console runs in the same way as all the other VMs. There is another hypervizor available from VMware which is called ESXi and it has exactly the same VMkernel as ESX has, but there is no service console available on ESXi. This concept is more clear with the new platform called vSphere, where ESX is an essential part of - there is still that service console based on RHEL, but you can see it as a VM with it's own virtual disk (VMDK). In case of any interruption inside the RHEL in service console, it does not affect any other VMs running on the hypervizor.. The hypervizor of ESX is standalone !

[Ruža Becelin]

hypervizor -> hypervisor, jinak OK

[deda.jabko]

x32_64bit

huh?! ;-]