If you look in the API documentation you'll notice that it's broken into two parts..."cluster" and "vserver". While there is some overlap, there are many APIs which must be targeted at SVMs and vice versa. In particular APIs which manipulate volumes and volume access are targeted at SVMs.
SVM level APIs can be invoked by connecting to the SVM management interface or by using tunneling through the cluster management interface.
Hope that helps.
If this post resolved your issue, please help others by selecting ACCEPT AS SOLUTION or adding a KUDO.
ONTAP White-list API
The Data ONTAP 7-Mode APIs that do not create, modify, or delete a cluster object are called ONTAP White-list APIs. A user in a cluster environment can use these 7-Mode API by using Storage Virtual Machine (SVM, formerly known as Vserver) tunneling.