Can someone explain ESXi, vCenter and vSphere ?

[vito_cavallo]

I am researching what I need to create a virtual server.  Can someone give me short explanations of the different related products?

I understand that ESXi is the hypervisor and installed to bare metal.

What is vCenter?  Do I need to purchase it or does it come with ESXi?

Can I just purchase ESXi?

What is vSphere used for if I have vCenter?

Thank you.

[mikelane]

vCenter is a physical or virtual server that you connect to to manage multiple vSphere servers.

vSphere is the new name for ESX / ESXi.

vSphere has a free version that you can install - if you purchase vSphere you are going to be purchasing licences for multiple installlations of vSphere with particular and progressively more advanced features as well as a licence for vCenter.

[vito_cavallo]

Thank you for the quick response, it is helpful.

I do not have a bare metal available to install the free version, but what is used to create and maintain VMs on just one server without vCenter?

Is that  vSphere web client?

Thank you.

[Dave_Mishchenko]

With a single ESXi install you can use the vSphere client to manage the host.  It requires a Windows workstation for the install.  The vSphere client is the same one you would use to manage a vCenter install.

[werewolf07]

1) VMware vSphere ESXi is the hypervisor you need to install on a server (you can download it for free)

2) VMware vSphere is the name of the suite that contains a lot of components (example: ESXi) and features that you can use to take advantage of from the ESXi hosts. This is based on the vSphere license/edition you purchase. You can see what each edition features: http://www.vmware.com/vmwarestore/vsphere_purchaseoptions.html

3) VMware vCenter is a Management tool to manage multiple vSphere ESXi hosts and virtual machines

4) vSphere Client is a client tool that you use to connect to your ESXi server or to a vCenter server to manage ESXi host/s and Virtual Machines

If you want to install ESXi and use its basic features, you do not have to purchase the license. You can just use the free edition.

EDIT: vSphere Web Client is a new component featured in vSphere 5.0 that lets you manage ESXi hosts and virtual machines. It is a light-weight component. This is basically a stripped down version of vSphere Client, that runs over the web.