[occi-wg] Advance Reservation Capabilities (ARC) for OCCi

thomas.roeblitz at tu-dortmund.de thomas.roeblitz at tu-dortmund.de
Fri Oct 22 09:13:08 CDT 2010

Hi All,

   we currently develop mechanisms for reserving VMs in advance. We 
thought it would be a welcome addition to the OCCi spec, most likely 
you're already working on such capabilities. We're happy to join that 
activity. Philipp and Ramin will attend OGF 30 and may participate in 
ongoing discussions.

Our use cases are

(1) set of VMs for a specific time slot,
(2) set of VMs for a set of specific time slots, and
(3) set of VMs, each VM for a specific duration to be finished before
some deadline (global to the set).

Related use cases in OCCi [1]:
- 2.1 SLA at SOI -- particularly, "scheduling information"
- 2.3 Interop w ONE -- particularly, "Quality of Service"
- 2.7 Automated Business Continuity ... -- particularly, "Quality of 
- 2.12 Multiple Allocation -- particularly, "Definition of groups"

A possible approach for ARC support would be to associate an attribute 
'timespec' with each resource entity (VM) and/or set of resource 
entities (VMs, didn't check if the current OCCi spec provides that 
possibility). The timespec's format could be based on the ISO 8601 
definition [2]. It would be sufficient for our use cases (except for 
irregular sets of time slots). Another option could be the webcal
specification [3].

Similarly, reservation identifiers could be passed through (e.g., for 
starting VMs).

There may be different options for how actually extending the spec.

A subsequent issue is the relationship of reservations and allocations 
of VMs, e.g. 1:1, 1:N, N:1, N:M.

Another aspect would be lifecycle management, particularly how do you
manage failures (before and during runtime of a reservation). Think of 
support for notification and recovery.

When we consider reserving VMs from multiple providers, transactional
aspects may be of interest as well, e.g., as previously done for Grid 
computing [4]. But that may be a bit far into the future?

What do you think about it ? Anybody else working on reservation of 
Cloud resources ?

Best regards,


[1] Open Cloud Computing Interface - Use cases and requirements for a 
Cloud API, http://forge.ogf.org/sf/go/doc15732

[2] ISO 8601 @ Wikipedia, http://en.wikipedia.org/wiki/ISO_8601

[3] webcal @ Wikipedia, http://en.wikipedia.org/wiki/Webcal

[4] HARC, https://www.cct.lsu.edu/harc.php

Thomas Röblitz / TU Dortmund / ITMC & LS Service Computing / Computer 
Science Department / +49-231-7555329

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