People who are new to VMware’s virtualization platform often get confused while learning VMware vSphere and its components. So today I will be explaining all about vSphere and its components. There are many components of VMware vSphere solution. It’s important to know the difference between vSphere, ESXi and vCenter. To get in-depth knowledge and experience in vSphere you can install vSphere inside VMware Workstation.
Difference between vSphere, ESXi and vCenter
VMware Inc. is a software company that develops many suites of software products specially for providing various virtualization solutions. There are many cloud products, datacenter products, desktop products and so on.
vSphere is a software suite that comes under data center product. vSphere is like Microsoft Office suite which has many softwares like MS Office, MS Excel, MS Access and so on. Like Microsoft Office, vSphere is also a software suite that has many software components like vCenter, ESXi, vSphere client and so on. So, the combination of all these software components is vSphere. vSphere is not a particular software that you can install and use, “it is just a package name which has other sub components”.
ESXi, vSphere client and vCenter are components of VMware vSphere. ESXi server is the most important part of vSphere. ESXi is the virtualization server. It is type 1 hypervisor. All the virtual machines or Guest OS are installed on ESXi server. To install, manage and access those virtual servers which sit above of ESXi server, you will need other part of vSphere suite called vSphere client. Now, vSphere client allows administrators to connect to ESXi servers and access or manage virtual machines. vSphere client is HTML5/web based management portal. The Administrator logs into Web Browser to access vSphere client in order to manage ESXi servers. vSphere Client for Windows or C# vSphere client is not longer available and is replaced by HTML5 based vSphere client in vSphere 6.7 eliminating the need for installing vSphere Client software to access ESXi host. So now what is vCenter? Why we need it? Try cloning existing virtual machine using just a vSphere client without vCenter server.
vCenter server is another piece of vSphere suite. There are two flavors of vCenter servers. vCenter server can be installed on Windows Server or can be Linux based virtual appliance. VMware will discontinue Winodws based vCenter server and release only Linux based vCenter appliance in the future. VMware vCenter server is a centralized management application that lets you manage virtual machines and ESXi hosts centrally. vSphere client again is used to access vCenter Server and ultimately manage ESXi servers. vCenter server is compulsory for enterprises that needs enterprise features like vMotion, VMware High Availability, VMware Update Manager, VMware Distributed Resource Scheduler (DRS) etc. For example, you can easily clone existing virtual machine in vCenter server. So vCenter is another important part of vSphere suite. You have to purchase vCenter server license separately.
The diagram above shows vSphere suite in a more descriptive way. vSphere is a product suite, ESXi is a hypervisor installed on a physical machine. vSphere Client HTML5 is used to access ESXi Server to create and manage virtual machines on ESXi server. vCenter server is installed as virtual machine on top of ESXi server, it can also be Linux based virtual machine (or virtual appliance). vCenter server can also be installed on different standalone physical server, but why not virtualize it too right? vCenter server is a vSphere component which is mostly used in large environment where there are many ESXi hosts and virtual machines and require advanced enterprise features of vSphere. The vCenter server is also accessed by vSphere client for management purpose. So, vSphere client is used to access ESXi server directly in small environment. In larger environment, vSphere client is used again to access vCenter server to manages ESXi server.