According to the install documentation, VMware vSphere 4 ESX and ESXi 4.1 update 1 are supported.
Install or upgrade to vCloud Director 1.5 will fail with the following error when trying to add the provider vDC:
Could not retrieve state for sequence: seq_os
This is easily fixed by editing the database table [os_id] and inserting the relevant information.
For ESX:
- [os_type] = vmnix-x86
- [name] = VMware ESX
- [version] = 4.1.0
- [update_level] = 1
- [is_supported] = 1
And for ESXi:
- [os_type] = vmnix-x86
- [name] = VMware ESXi
- [version] = 4.1.0
- [update_level] = 1
- [is_supported] = 1
then restart the setup of your provider vDC and you should be all set.