You perform host profiles tasks in a certain workflow order.
You must have an existing vSphere installation with at least one properly configured host.
Set up and configure the host that will be used as the reference host.
A reference host is the host from which the profile is created.
Create a profile using the designated reference host.
Attach a host or cluster to the profile.
Check the host's compliance to the reference host's profile. If all hosts are compliant with the reference host, they are correctly configured.
Apply the host profile of the reference host to other hosts or clusters of hosts.
Using host profiles is only supported for VMware vSphere 4.0 hosts or later. This feature is not supported for VMware Infrastructure 3.5 or earlier hosts. If you have VMware Infrastructure 3.5 or earlier hosts managed by your vCenter Server 4.0 or later, the following problems can occur if you try to use host profiles for those hosts:
You cannot create a host profile that uses a VMware Infrastructure 3.5 or earlier host as a reference host.
You cannot apply a host profile to any VMware Infrastructure 3.5 or earlier hosts. The compliance check fails.
While you can attach a host profile to a mixed cluster that contains VMware Infrastructure 3.5 or earlier hosts, the compliance check for those earlier hosts fails.
As a licensed feature of vSphere, host profiles are only available when the appropriate licensing is in place. If you see errors, ensure that you have the appropriate vSphere licensing for your hosts.
If you want the host profile to use directory services for authentication, the reference host needs to be configured to use a directory service. See the vSphere Security documentation.
Hosts Provisioned with vSphere® Auto Deploy
For hosts provisioned with vSphere Auto Deploy, vCenter Server owns the entire host configuration, which is captured in a host profile. In most cases, the host profile information is sufficient to store all configuration information. Sometimes the user is prompted for input when the host provisioned with Auto Deploy boots. The answer file mechanism manages those cases. See the vSphere Installation and Setup documentation.