I was really confused with the terms Vsphere , Vcenter and ESXi and i have thought to write up the difference so that it might help someone at some point of time
What is vSphere ?
vSphere is suite of products packaged shipped by VMware virtualization company, which includes products. Like VMware ESXi hypervisor, VMware vCenter Server, etc.
VMware ESXi ?
ESXi or hypervisor is bare metal OS which virtualizes x86 server hardware. You use ESXi ( OS ) installation media to install OS on top of hardware just like you install any other OS like Windows or Linux
Once you have VMware ESXi installed on a x86 server hardware I is ready to virtualized. What does it mean ? - It means you can now use same server to create , configure, run more than one virtual machines and install required Operating systems within Virtual Machines they are referred as Guest Operating systems which could be Windows or Linux etc
What is vCenter ?
Vcenter is another Vmware product used to manage one or more ESXi servers comes in the Vsphere software package.