Please distinguish :
- splunkcloud as a service, that is hosted on Amazon and is managed/deployed for you, in which the splunk license is included in the price and not accessible to the user.
- regular Splunk enterprise/hunk etc.. deployed by you on a server that happen to be in the cloud, in this case you will need to buy a license, or link the indexers to an existing license-master if you already have one,
@esix is correct however since his answer, the process has changed. You can open a regular support case to obtain a license specifically for on-premises infrastructure such as deployment servers or HF in the case that you do need a license. (UF's do not need a separate license.)