CLOUD COMPUTING
Lecturer:
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NTRODUCTION
Cloud computing has emerged as a paradigm to deliver on-demand resources (e.g., infrastructure, platform, software, etc.) to customers. The three main services are provided by the Cloud computing architecture according to the needs of IT customers. Firstly, Software as a Service (SaaS) provides access to complete applications as a service, such as Customer Relationship Management (CRM). Secondly, Platform as a Service (PaaS) provides a platform for developing other applications on top of it, such as the Google App Engine (GAE). Finally, Infrastructure as a Service (IaaS) provides an environment for deploying, running and managing virtual machines and storage. Technically, IaaS offers incremental scalability (scale up and down) of computing resources and on-demand storage.
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Software as a Service (SaaS) – The capability provided to the consumer is to use the provider’s applications running on a cloud infrastructure. The applications are accessible from various client devices through a thin client interface such as a Web browser (e.g., Web-based email), or a program interface. The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, storage, or even individual application capabilities, with the possible exception of limited user-specific application configuration settings.
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Private cloud – The cloud infrastructure is provisioned for exclusive use by a single organization comprising multiple consumers. It may be owned, managed, and operated by the organization, a third party, or some combination of them, and it may exist on or off premises.
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Public cloud – The cloud infrastructure is provisioned for open use by the general public. It may be owned, managed, and operated by a business, academic, or government organization, or some combination of them. It exists on the premises of the cloud provider.
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SaaS is also known commonly as «Web services». SaaS systems can be implemented in a number of different ways. The most advanced architectures for SaaS appear to satisfy the NIST definition of cloud computing. While many slightly different definitions of SaaS are possible, a simple and usable definition has already been formulated:
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IaaS:
Who are the consumers? – System administrators.
What does a consumer get? – Access to virtual computers, network-accessible
storage, and network infrastructure components such as firewalls, and configuration services.
How are usage fees calculated? – Typically, per cpu hour, data GB stored per
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Quality model and metrics for cloud KPIs:
1. Service response time. 2. Sustainability: GEC PUE ITEE ITEU Energy Carbon Work Center Data DPPE 1 1 1 h] cturer)[KW (by manufa Energy IT ification Total Spec Wh] y of IT [K ured Energ Total Meas ITEU= h] cturer)[KW (by manufa Energy IT ification Total Spec y NW capacit pacity+c Storage Ca acity+b Server Cap a
ITEE
mption ower Consu
DC Total P
gy Green Ener GEC
3. Suitability:
; 0 ; 1 otherwise satisfied are features all if N N y Suitabilit C NEF S NEF
where – number of non-essential features provided by service; – number of non-essential features required by the customer if only essential requirements are satisfied.
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Quality model and metrics for cloud KPIs:
4. Accuracy. 5. Transparency. 6. Interoperability:
ity eroperabil r
y users fo required b platforms number of der the provi offered by platforms number of I int
7. Availability:
s total NA total s total T -T T A
8. Reliability: RPviolationPmttf
mttf
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where - the promised mean time to failure.
9. Stability. 10. Cost.
11. Adaptability. 12. Usability.
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The cost functions are:
