API Overview

EVS APIs include custom APIs and OpenStack Cinder APIs.

Custom APIs do not depend on OpenStack, and OpenStack Cinder APIs depend on OpenStack. A combination of these two types of APIs allows you to use all EVS functions.

**Table 1** API overview
Type	Subtype	Description
API	EVS disk	These APIs provide the functions, such as creating disks, deleting disks, and querying disk details.
	EVS snapshot	An EVS snapshot is a complete copy or image of the disk data at a specific time point. These APIs provide the function of rolling back the snapshot data to the disk.
	EVS tag	Tags are used to identify the cloud resources for purposes of easy categorization and quick search. These APIs provide the functions, such as adding, deleting, and querying tags.
OpenStack Cinder API	EVS disk	These APIs provide the functions, such as creating disks, updating disks, querying disks, querying images, and querying quotas.
	EVS disk action	These APIs provide the functions, such as expanding disks, reserving disks, exporting disk data as images, and setting the bootable attribute for disks.
	EVS snapshot	An EVS snapshot is a complete copy or image of the disk data at a specific time point. These APIs provide the functions, such as creating snapshots, querying snapshots, updating snapshot metadata, and querying snapshot metadata.
	EVS disk transfer	Through the disk transfer function, disks can be transferred from one tenant to another. After the transfer succeeds, the ownerships of the disks belong to the target tenant only. These APIs provide the functions, such as creating, accepting, deleting, and querying disk transfers.