[Fiware-cloud] Terms and Definitions -- YOUR INPUT IS NEEDED

[David Breitgand]

SLAs and SLOs -- [David, can you, please, provide a definition?] 


Service Level Agreement (SLA) is legally binding contract between a 
service provider and a service consumer specifying terms and conditions of 
service provisioning and consumption. Specific SLA clauses define 
non-functional aspects of service provisioning such as performance, 
resiliency, high availability, security, maintenance, etc., along with the 
agreed upon means for verifying SLA compliance, customer compensation plan 
that should be put in effect in case of SLA incompliance, and temporal 
framework that defines validity of the contract. SLAs, usually, come in 
two forms: (a) standard SLAs and (b) individual (customized) SLAs. In the 
former type of SLAs, the SLA clauses are standardized for all customers, 
in the  latter type of SLAs, the clauses are developed through a 
negotiation process between the customer and provider.


Service Level Objective (SLO) is a clause of an SLA that defines 
measurable technical artefact defining the target level of provisioning of 
a certain non-functional property of a service, for example, performance. 
Performance SLO may be defined to specify the required target level for 
average, maximum, and specific percentile (e.g., 95.5 percentile) of 
response times  per transaction type in a transactional application, 



From:   Alex Glikson/Haifa/IBM at IBMIL
To:     fiware-cloud at lists.fi-ware.eu
Date:   21/06/2011 05:29 PM
Subject:        [Fiware-cloud] Terms and Definitions -- YOUR INPUT IS 
NEEDED
Sent by:        fiware-cloud-bounces at lists.fi-ware.eu



Please, see below the list of terms with their current descriptions for 
the HLDesc. Notice that I've refactored and/or consolidated some of the 
definitions. 
I've marked in blue places where I need your input. Of course, any other 
comments/suggestions are welcome. 

Thanks, 
Alex 

Infrastructure as a Service (IaaS) -- a model of delivering 
general-purpose virtual machines (VMs) and associated resources (CPU, 
memory, disk space, network connectivity) on-demand, typically via a 
self-service interface and following a pay-per-use pricing model. The 
virtual machines can be directly accessed and used by the IaaS consumer 
(e.g., an application developer, an IT provider or a service provider), to 
easily deploy and manage arbitrary software stacks. 

Platform as a Service (PaaS) -- an application delivery model in which the 
clients, typically application developers, follow a specific programming 
model to develop their applications and or application components and then 
deploy them in hosted runtime environments.  This model enables fast 
development and deployment of new applications and components. 

Virtual Appliances (vApp, also referred to as "service") -- pre-built 
software solutions, comprised of one or more Virtual Machines that are 
packaged, updated, maintained and managed as a unit. Virtual appliances 
are typically packaged in an Open Virtualization Format (OVF), developed 
by Distributed Management Task Force (DMTF) standardization body. 

Key Performance Indicators (KPIs) -- quantifiable metrics reflecting the 
level of offered service with respect to specific non-functional 
requirements such as performance, availability, resiliency, etc. KPI is 
usually computed as a function of one or more low level metrics. KPIs may 
relate either to the long term measures of the service level where raw 
metrics are averaged and summarized over a long time scale to guide 
strategic decisions about the service provisioning, or short term measures 
of service level, triggering proactive optimization. 

Service Elasticity  is the capability of the hosting infrastructure to 
scale a service up and down on demand. There are two types of elasticity 
-- vertical (typically of a single VM), implying the ability to add or 
remove resources to a running VM instance, and horizontal (typically of a 
clustered multi-VM service), implying the ability to add or remove 
instances to/from an application cluster, on-demand. Elasticity can be 
triggered manually by the user, or via an Auto-Scaling framework, 
providing the capability to define and enforce automated elasticity 
policies based on application-specific KPIs. 

SLAs and SLOs -- [David, can you, please, provide a definition?] 

Cloud Edge -- [Serge, can you, please, provide a non-recursive definition?
] a set of devices at the edge of the cloud. May correspond to end-devices 
[Serge: not clear what is 'end-device'] or to a more complex structure 
like a home network with end-devices and a Cloud Proxy -- a special device 
located in the home network and offering storage and computing 
capabilities to the cloud applications so that they can use it as their 
agent  close to the end-devices [Serge, please, specify the purpose 
instead of saying "agent"-- e.g., improved user experience, security, etc]
. 

TCloud API -- [Fernando, can you, please, provide a concise, 
self-explanatory definition?] 

OCCI -- [Andy, can you, please, provide a definition?] 

Cloud Data Management Interface (CDMI) defines the functional interface 
that applications will use to create, retrieve, update and delete (CRUD) 
data elements from the Cloud defined by the Storage Networking Industry 
Association (SNIA) group 


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