In vSphere, a permission consists of a user or group and an assigned role for an inventory object, such as a virtual machine or ESX/ESXi host. Permissions grant users the right to perform the activities specified by the role on the object to which the role is assigned.

For example, to configure memory for an ESX/ESXi host, a user must be granted a role that includes the Host.Configuration.Memory Configuration privilege. By assigning different roles to users or groups for different objects, you can precisely control the tasks that users can perform in your vSphere environment.

The Conceptual Structure of a Permission
structure of a permission

By default, all users who are members of the Windows Administrators group on the vCenter Server system have the same access rights as any user assigned to the Administrator role on all objects. When connecting directly to an ESX/ESXi host, the root and vpxuser user accounts have the same access rights as any user assigned the Administrator role on all objects.

All other users initially have no permissions on any objects, which means they cannot view these objects or perform operations on them. A user with Administrator privileges must assign permissions to these users to allow them to perform necessary tasks.

Many tasks require permissions on more than one object. Some general rules can help you determine where you must assign permissions to allow particular operations:

Any operation that consumes storage space, such as creating a virtual disk or taking a snapshot, requires the Datastore.Allocate Space privilege on the target datastore, as well as the privilege to perform the operation itself.

Moving an object in the inventory hierarchy requires appropriate privileges on the object itself, the source parent object (such as a folder or cluster), and the destination parent object.

Each host and cluster has its own implicit resource pool that contains all the resources of that host or cluster. Deploying a virtual machine directly to a host or cluster requires the Resource.Assign Virtual Machine to Resource Pool privilege.