1. ITM 711: Cloud Computing: Fundamental Models

2. Outline
• Fundamental Models
• Cloud Computing Roles
• Cloud Characteristics
• Cloud Delivery Models
• Cloud Deployment Models
2

3. Cloud Computing Roles

4. Cloud Computing Roles
4
• Cloud Provider
• Cloud Consumer
• Cloud Service Owner
• Cloud Resource Administrator
• Cloud Auditor
• Cloud Broker
• Cloud Carrier

5. From Cloud Computing by Thomas Erl, Zaigham Mahmood, and Ricardo Puttini
(ISBN: 0133387526) Copyright © 2013 Arcitura Education, Inc. All rights reserved.
Figure 4.1 A cloud consumer (Organization A) interacts with a cloud service from a cloud provider (that owns Cloud A).
Within Organization A, the cloud service consumer is being used to access the cloud service.
Cloud Computing Roles: Cloud Provider & Cloud Consumer

6. From Cloud Computing by Thomas Erl, Zaigham Mahmood, and Ricardo Puttini
(ISBN: 0133387526) Copyright © 2013 Arcitura Education, Inc. All rights reserved.
Figure 4.2 A cloud consumer can be a cloud service owner when it deploys its own service in a cloud.
Cloud Computing Roles: Cloud Service Owner -1/2

7. From Cloud Computing by Thomas Erl, Zaigham Mahmood, and Ricardo Puttini
(ISBN: 0133387526) Copyright © 2013 Arcitura Education, Inc. All rights reserved.
Figure 4.3 A cloud provider becomes a cloud service owner if it deploys its own cloud service, typically for other cloud consumers to use.
Cloud Computing Roles: Cloud Service Owner -2/2

8. Figure 4.4 A cloud resource administrator can be with a cloud consumer organization and administer
remotely accessible IT resources that belong to the cloud consumer.
Cloud Computing Roles: Cloud Resource Administrator -1/2

9. From Cloud Computing by Thomas Erl, Zaigham Mahmood, and Ricardo Puttini
(ISBN: 0133387526) Copyright © 2013 Arcitura Education, Inc. All rights reserved.
Figure 4.5 A cloud resource administrator can be with a cloud provider organization for which it can
administer the cloud provider’s internally and externally available IT resources.
Cloud Computing Roles: Cloud Resource Administrator -2/2

10. Cloud Computing Roles: Cloud Auditor
• A third-party (often accredited) that conducts independent
unbiased assessment of cloud environments to help strengthen
the trust relationship between cloud consumers and cloud
providers.
• Cloud Auditor is responsible for the evaluation of
– security controls
– privacy impacts
– performance

11. Cloud Computing Roles: Cloud Broker & Cloud Carrier
• Cloud Broker: Responsible of managing and negotiating the usage
of cloud services between cloud consumers and cloud providers.
• Cloud Carrier: Responsible for providing the wire-level connectivity
between cloud consumers and cloud providers

12. Cloud Characteristics

13. Cloud Characteristics
13
• On-demand usage
– ability of a cloud consumer to self-provision and use necessary cloud-based services without requiring
cloud provider interaction
• Ubiquitous access
– support for a range of devices, transport protocols, interfaces, and security technologies
• Multi-tenancy (and resource pooling)
– ability of an instance of the program to serve different consumers
• Elasticity
– ability of a cloud to transparently scale IT resources
• Measured usage
– ability to keep track of the usage of its IT resources
• Resiliency
– Failover through redundant implementations of IT resources across physical locations

14. From Cloud Computing by Thomas Erl, Zaigham Mahmood, and Ricardo Puttini
(ISBN: 0133387526) Copyright © 2013 Arcitura Education, Inc. All rights reserved.
Figure 4.6 Organizational boundaries of a cloud consumer (left), and a cloud provider (right),
represented by a broken line notation.
Cloud Characteristics: Organizational Boundaries

15. From Cloud Computing by Thomas Erl, Zaigham Mahmood, and Ricardo Puttini
(ISBN: 0133387526) Copyright © 2013 Arcitura Education, Inc. All rights reserved.
Figure 4.7 An extended trust boundary encompasses the organizational boundaries of the cloud provider
and the cloud consumer.
Cloud Characteristics: Organizational Trust Boundaries

16. From Cloud Computing by Thomas Erl, Zaigham Mahmood, and Ricardo Puttini
(ISBN: 0133387526) Copyright © 2013 Arcitura Education, Inc. All rights reserved.
Figure 4.8 In a single-tenant environment, each cloud consumer has a separate IT resource instance.
Cloud Characteristics: Single-Tenant Environment

17. From Cloud Computing by Thomas Erl, Zaigham Mahmood, and Ricardo Puttini
(ISBN: 0133387526) Copyright © 2013 Arcitura Education, Inc. All rights reserved.
Figure 4.9 In a multitenant environment, a single instance of an IT resource, such as a cloud storage
device, serves multiple consumers.
Cloud Characteristics: Multi-Tenant Environment

18. From Cloud Computing by Thomas Erl, Zaigham Mahmood, and Ricardo Puttini
(ISBN: 0133387526) Copyright © 2013 Arcitura Education, Inc. All rights reserved.
Figure 4.10 A resilient system in which Cloud B hosts a redundant implementation of Cloud Service A
to provide failover in case Cloud Service A on Cloud A becomes unavailable.
Cloud Characteristics: Resiliency

19. Cloud Delivery Models

20. Cloud Computing: Providers
20
https://xyfon.com/how-to-pick-the-right-cloud-provider-your-business/

21. From Cloud Computing by Thomas Erl, Zaigham Mahmood, and Ricardo Puttini
(ISBN: 0133387526) Copyright © 2013 Arcitura Education, Inc. All rights reserved.
Figure 3.8 An example of an organization’s changing demand for an IT resource over the course of a day.
Business Demand vs. IT Resource Need

22. From Cloud Computing by Thomas Erl, Zaigham Mahmood, and Ricardo Puttini
(ISBN: 0133387526) Copyright © 2013 Arcitura Education, Inc. All rights reserved.
Figure 4.11 A cloud consumer is using a virtual server within an IaaS environment. Cloud consumers are
provided with a range of contractual guarantees by the cloud provider, pertaining to characteristics
such as capacity, performance, and availability.
Cloud Delivery Models: Infrastructure as a Service (IaaS)

23. Cloud Delivery Models: Infrastructure as a Service (IaaS): Building -1/4
• The two most fundamental IT resources that are delivered:
– virtual server
– cloud storage device
• Standardized configurations properties:
– Operating system
– Primary memory capacity
– Processing capacity
– Virtualized storage capacity

24. Cloud Delivery Models: Infrastructure as a Service (IaaS): Building -2/4
• IaaS offerings are preemptively assembled by cloud providers via virtual
server images that capture the pre-defined configurations
• May offer cloud consumers direct administrative access to physical IT
resources
• Snapshots can be taken of a virtual server to record its current state,
memory, and configuration
• Horizontal and vertical scaling
– duplicate a virtual server
– backup and replication purposes
– import and export options for custom-built virtual server

25. Cloud Delivery Models: Infrastructure as a Service (IaaS): Building -3/4
• Multiple geographically-diverse data centers
– Can be linked together for increased resiliency
– Connected through high-speed communications networks with low latency
– Can perform load balancing
– IT resource backup and replication
– Increase storage capacity
– Improving availability and reliability

26. From Cloud Computing by Thomas Erl, Zaigham Mahmood, and Ricardo Puttini
(ISBN: 0133387526) Copyright © 2013 Arcitura Education, Inc. All rights reserved.
Figure 14.1 A cloud provider is provisioning and managing an IaaS environment with IT resources from different
data centers in the United States and the United Kingdom.
Cloud Delivery Models: Infrastructure as a Service (IaaS): Building -4/4

27. From Cloud Computing by Thomas Erl, Zaigham Mahmood, and Ricardo Puttini
(ISBN: 0133387526) Copyright © 2013 Arcitura Education, Inc. All rights reserved.
Figure 4.12 A cloud consumer is accessing a ready-made PaaS environment. The question mark indicates
that the cloud consumer is intentionally shielded from the implementation details of the platform.
Cloud Delivery Models: Platform as a Service (PaaS)

28. Cloud Delivery Models: Platform as a Service (PaaS): Equipping
• Equipped with a selection of application development and deployment platforms in order to
accommodate different programming models, languages, and frameworks
• A separate ready-made environment is usually created for each programming stack that
contains the necessary software to run applications specifically developed for the platform
• Consumers can create and control customized virtual server images with ready-made
environments
• Also provides features, such as managing deployed applications and configuring
multitenancy
• The PaaS environment, by default, usually relies on the cloud security mechanisms
provisioned for IaaS environments

29. From Cloud Computing by Thomas Erl, Zaigham Mahmood, and Ricardo Puttini
(ISBN: 0133387526) Copyright © 2013 Arcitura Education, Inc. All rights reserved.
Figure 4.13 The cloud service consumer is given access the cloud service contract, but not to any
underlying IT resources or implementation details.
Cloud Delivery Models: Software as a Service (SaaS)

30. Cloud Delivery Models: Software as a Service (SaaS): Optimizing -1/6
Diversity of Functionality
• Collaborative authoring and information-sharing (Wikipedia, Blogger)
• Collaborative management (Zimbra, Google Apps)
• Conferencing services for instant messaging, audio/video
communications (Skype,Google Talk)
• Enterprise management systems (ERP, CRM)
• Video/File-sharing and content distribution (YouTube, Dropbox)
• Industry-specific software (engineering, bioinformatics)
• Messaging systems (e-mail, voicemail)
• Mobile application marketplaces (Android Play Store, Apple App Store)
• Office productivity software suites (Microsoft Office, Adobe Creative Cloud)
• Search engines (Google, Yahoo)
• Social networking media (Instagram, Twitter, LinkedIn)

31. Cloud Delivery Models: Software as a Service (SaaS): Optimizing -2/6
Diversity of Implementation Mediums
• Mobile application
• REST service (Representational State Transfer)
• Web service (e.g. SOAP)
• Each of these SaaS implementation mediums provide Web-based APIs
for interfacing by cloud consumers.
• Examples of online SaaS-based cloud services with Web-based APIs include:
– Electronic payment services (PayPal)
– Mapping and routing services (Google Maps)
– Publishing tools (WordPress)

32. Cloud Delivery Models: Software as a Service (SaaS): Optimizing -3/6
Specialized Processing Requirements
• Service Load Balancing – for workload distribution across redundant SaaS-based cloud service
implementations
• Dynamic Failure Detection and Recovery – to establish a system that can automatically resolve
some failure conditions without disruption in service to the SaaS implementation
• Storage Maintenance Window – to allow for planned maintenance outages that do not impact
SaaS implementation availability
• Elastic Resource Capacity/Elastic Network Capacity – to establish inherent elasticity within the
SaaS-based cloud service architecture that enables it to automatically accommodate a range of
runtime scalability requirements
• Cloud Balancing – to instill broad resiliency within the SaaS implementation, which can be
especially important for cloud services subjected to extreme concurrent usage volumes

33. Cloud Delivery Models: Software as a Service (SaaS): Optimizing -4/6
• Tenant Subscription Period – This metric is used by pay-per-use monitors to record and track
application usage for time-based billing. This type of monitoring usually incorporates
application licensing and regular assessments of leasing periods that extend beyond the
hourly periods of IaaS and PaaS environments
• Application Usage – This metric, based on user or security groups, is used with pay-per-use
monitors to record and track application usage for billing purposes
• Tenant Application Functional Module – This metric is used by pay-per-use monitors for
function-based billing. Cloud services can have different functionality tiers according to
whether the cloud consumer is free-tier or a paid subscriber
• Similar in IaaS and PaaS implementations, SaaS environments are also commonly monitored
for data storage, network traffic, failure conditions, and event triggers.

34. From Cloud Computing by Thomas Erl, Zaigham Mahmood, and Ricardo Puttini
(ISBN: 0133387526) Copyright © 2013 Arcitura Education, Inc. All rights reserved.
Figure 4.14 A PaaS environment based on the IT resources provided by an underlying IaaS environment.
Cloud Delivery Models: Iaas + PaaS -1/2

35. From Cloud Computing by Thomas Erl, Zaigham Mahmood, and Ricardo Puttini
(ISBN: 0133387526) Copyright © 2013 Arcitura Education, Inc. All rights reserved.
Figure 4.15 An example of a contract between Cloud Providers X and Y, in which services offered by Cloud Provider X are physically
hosted on virtual servers belonging to Cloud Provider Y.
Sensitive data that is legally required to stay in a specific region is physically kept in Cloud B, which is physically located in that region.
Cloud Delivery Models: Iaas + PaaS -2/2

36. From Cloud Computing by Thomas Erl, Zaigham Mahmood, and Ricardo Puttini
(ISBN: 0133387526) Copyright © 2013 Arcitura Education, Inc. All rights reserved.
Figure 4.16 A simple layered view of an architecture comprised of IaaS and PaaS environments
hosting three SaaS cloud service implementations.
Cloud Delivery Models: Iaas + PaaS + SaaS

37. Cloud Delivery Models: Comparison: Level of Control

38. Cloud Delivery Models: Comparison: Division of Labour

39. Cloud Deployment Models

40. Cloud Deployment Models
• A cloud deployment model represents a specific type of cloud
environment, primarily distinguished by
• Ownership
• Size
• Access
• Four common cloud deployment models:
• Public cloud
• Community cloud
• Private cloud
• Hybrid cloud

41. Cloud Deployment Models: Public Cloud
• A public cloud is a publicly accessible cloud environment owned by a
third-party cloud provider
• The IT resources on public clouds are usually provisioned via the
previously described cloud delivery models and are generally offered to
cloud consumers at a cost or are commercialized via other avenues
(such as advertisement)
• The cloud provider is responsible for the creation and on-going
maintenance of the public cloud and its IT resources

42. From Cloud Computing by Thomas Erl, Zaigham Mahmood, and Ricardo Puttini
(ISBN: 0133387526) Copyright © 2013 Arcitura Education, Inc. All rights reserved.
Cloud Deployment Models: Public Cloud: Example
Figure 4.17 Organizations act as cloud consumers when accessing cloud services and IT resources made available by different cloud providers.

43. Cloud Deployment Models: Community Cloud
• A community cloud is similar to a public cloud except that its
access is limited to a specific community of cloud consumers
• The community cloud may be jointly owned by the community
members or by a third-party cloud provider that provisions a public
cloud with limited access
• The member cloud consumers of the community typically share
the responsibility for defining and evolving the community cloud.

44. From Cloud Computing by Thomas Erl, Zaigham Mahmood, and Ricardo Puttini
(ISBN: 0133387526) Copyright © 2013 Arcitura Education, Inc. All rights reserved.
Figure 4.18 An example of a “community” of organizations accessing IT resources from a community cloud.
Cloud Deployment Models: Community Cloud: Example

45. Cloud Deployment Models: Private Cloud
• A private cloud is owned by a single organization
• Private clouds enable an organization to use cloud computing
technology as a means of centralizing access to IT resources by
different parts, locations, or departments of the organization

46. From Cloud Computing by Thomas Erl, Zaigham Mahmood, and Ricardo Puttini
(ISBN: 0133387526) Copyright © 2013 Arcitura Education, Inc. All rights reserved.
Figure 4.19 A cloud service consumer in the organization’s on-premise environment accesses a cloud service
hosted on the same organization’s private cloud via a virtual private network.
Cloud Deployment Models: Private Cloud: Example

47. Cloud Deployment Models: Hybrid Cloud
• A hybrid cloud is a cloud environment comprised of two or more
different cloud deployment models
• For example, a cloud consumer may choose to deploy cloud
services processing sensitive data to a private cloud and other,
less sensitive cloud services to a public cloud. The result of this
combination is a hybrid deployment model

48. From Cloud Computing by Thomas Erl, Zaigham Mahmood, and Ricardo Puttini
(ISBN: 0133387526) Copyright © 2013 Arcitura Education, Inc. All rights reserved.
Figure 4.20 An organization using a hybrid cloud architecture that utilizes both a private and public cloud.
Cloud Deployment Models: Hybrid Cloud: Example

49. Cloud Deployment Models: Other
• Virtual Private Cloud: Also known as a "dedicated cloud" or "hosted
cloud," this model results in a self-contained cloud environment
hosted and managed by a public cloud provider and made available
to a cloud consumer.
• Inter-Cloud: This model is based on an architecture comprised of two or
more inter-connected clouds .