StorageSnapshot API

Bug Reference

The Jira issue associated with this design spec

Branch

master

Introduction

Purpose

The objective of this API is to enable storage vendor side snapshots of virtual disk when using managed hardware as Primary Storage. When using the Primary storage plugins such as SolidFire vendor,  each virtual disks is a LUN on the storage array. Using the storage array snapshot capability benefits for performance and features sets supported by the storage vendor.

StorageSnapshot does not fit in the VolumeSnapshot API because it would not perform the same tasks, a Volume Snapshot use the hypervisor capability to create a volume snapshot then extract it and archive it into the secondary storage. The intent of a StorageSnapshot is to perform a snapshot at the hardware vendor level, and keep it there for rollback purposes and disk cloning. StorageSnapshot is more aligned with the VMsnapshot API capability but is intent to be per virtual disk basis.

. References

• relevant links

Document History

Glossary

Feature Specifications

• The initial scope of work is to define the API and enable it for infrastructure specific: SolidFire storage plugin with XenServer 6.5, but also create the API skeleton for other deployment scenario.
• When using VDI-per-LUN (storage plugin for vendor specific)
  • Create storage snapshots of a volume;
    • support multiple snapshots of the same volume.
    • keep track of snapshot inventory/hierarchy in cloudstack database.
  • Revert volume from a snapshot
  • Create new volume from a snapshot   "clone".
  • Scheduling auto snapshot ?
• UI would support the feature in the snapshot  drop down,  as "StorageSnapshot"

Use cases

When using VDI-per-LUN with  XenServer 6.5 + SolidFire storage array, all VirtualDisk are unique LUN on the storage array so it leverage snapshot capabilities of the storage vendor for volumes.

One XenServer as hypervisor constraint is that each VDI run on a dedicated SR, as the LUN is presented as a iSCSI-LVM SR dedicated for a single VDI. 

The StorageSnapshot API will be reuse by the VolumeSnapshot API when using storage plugin so the VolumeSnapshot would perform following task:

1. StorageSnapshot
2. Extraction of the snapshot as a reusable volume to the secondary storage
   1. as regular snapshot archive, or storage vendor format specific ,  TBD

Architecture and Design description

• The API skeleton should allow other storage vendors to implement their own methods
  
  

Web Services APIs

UI flow

• either demonstrate it visually here or link to relevant mockups

IP Clearance

• what dependencies will you be adding to the project?
• are you expecting to include any code developed outside the Apache CloudStack project?

Usage Impact

• Are there any entities being created that require usage reporting for billing purposes? 

• Does this change any existing entities for which usage is being tracked already?

Appendix

Appendix A:

Appendix B: