The Microsoft Dynamics GP 2015 image is available in the MSDN Azure gallery. This is a pretty cool way to provision GP.
Announcing, Microsoft Dynamics GP 2015 image available in the MSDN Azure gallery. – Microsoft Dynamics GP Community
Microsoft & the GP EcosystemGP 2015
Archived post from 2015. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.