There are three different types of modular OpenStack architecture have OpenStack Compute, OpenStack Object Storage and Image Service which are explained as below –
OpenStack Compute – The OpenStack Compute is used to manage larger networks of the virtual machine instances.
OpenStack Object Storage – The OpenStack Object Storage is used to provide the support services for both the Object Storage and Block Storage models.
Image Service– The Image Service is used to discover the delivery services and provides the registration services as well to the Virtual Disk Images.
Hope this will help you.