If you are deploying stateless ESXi hosts using vSphere Auto Deploy, then you should be packaging the vSphere HA FDM VIB into the image profile; otherwise, you won't be able to enable HA on the auto-deployed hosts.
The following procedure will guide you through the steps required in adding the FDM VIB to the image profile:
Connect-VIServerto add the vCenter server to the PowerCLI session:
Connect-VIServer -Server vcenterhost001 -User Administrator -Password pass123
Add-EsxSoftwareDepot -DepotUrl C:\Offline-Bundles\VMware-ESXi-5.5.0-1331820-depot.zip
http://IP or FQDN ...