Fundamental cloud computing

Asmaa Ibrahim
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Part I: Fundamental Cloud
Computing

Fundamental Cloud Computing
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 Chapter 1: Understanding Cloud Computing
 Chapter 2: Fundamental Concepts and
Models
 Chapter 3: Cloud-Enabling Technology
 Chapter 4: Fundamental Cloud Security

Understanding Cloud Computing
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 Origins and Influences
 Basic Concepts and Terminology

A Brief History
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“As of now, computer
networks are still in their
infancy, but as they grow up
and become sophisticated, we
will probably see the spread of
„computer utilities‟ …”.
Leonard Kleinrock

What is the next ??
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 Cloud computing is a new way of
delivering computing resources, not
a new technology.

Why Cloud Computing?
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 Business Drivers
 Capacity Planning
 Organizational Agility
 Cost Reduction
 Technology Innovations
 Clustering
 Grid Computing
 Virtualization

Organizational Agility
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Virtualization
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 Let’s talk about virtualization in details.

Virtualization History
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Virtualization Principles
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Server virtualization separates
software from hardware.
The low-layer virtualization
software abstracts a virtual
hardware interface by means of
space segmentation, time
division, and emulation to
provide the upper-layer OSs
with an expected hardware
environment.

Virtualization architecture
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Virtualization Implementation
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 VMM virtualizes three types of physical
resources: CPU, memory, and I/O device. CPU
virtualization is the most important.
 We will go through:
 CPU virtualization
 memory virtualization
 I/O device virtualization

1- CPU Virtualization
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 Classical virtualization method
 The modern computer architecture offers at least two levels of
privilege (user mode and kernel mode) to isolate system
software from application programs
 x86 virtualization method
 The x86 architecture offers four levels of privilege known as
Ring 0, 1, 2, and 3. The x86 has the following sensitive
instructions:
1. Instructions used to access and modify machine state or VM state
2. Instructions that read or change sensitive registers, such as a clock
register or interrupt registers, or memory locations
3. Instructions that reference the storage protection system, memory, or
address relocation system (such as paging)
4. All I/O instructions

x86 virtualization method
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2- Memory Virtualization
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3- I/O Device Virtualization
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 The VMM virtualizes I/O devices to reuse limited I/O
resources. It intercepts requests when guest OSs
attempt to access I/O devices and then uses software
to emulate real hardware. There are three types of I/O
device virtualization methods: complete emulation on
interface, front-end and back-end emulation, and
direct allocation.

Technology Innovations vs. Enabling
Technologies
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 These are distinguished as cloud-enabling
technologies:
 Broadband Networks and Internet Architecture
 Data Center Technology
 (Modern) Virtualization Technology
 Web Technology
 Multitenant Technology
 Service Technology

Basic Concepts and Terminology
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Cloud
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 A Cloud refers to a distinct IT environment that is
designed for the purpose of remotely provisioning
scalable and measured IT resources.
Figure 1.1
The symbol used to denote the boundary
of a cloud environment.

IT Resource
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 An IT resource is a physical or virtual IT-related
artifact that can be either software based, such as a
virtual server or a custom software program, or
hardware-based, such as a physical server or a
network device (Figure 1.2).
Figure 1.2
Examples of common IT resources and their corresponding
symbols.

Figure 1.3
A cloud is hosting eight IT resources: three virtual servers, two cloud
services, and three storage devices.
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On-Premise
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 An on-premise IT resource can access and
interact with a cloud-based IT resource.
 An on-premise IT resource can be moved to a
cloud, thereby changing it to a cloud-based IT
resource.
 Redundant deployments of an IT resource can
exist in both on-premise and cloud-based
environments.

Scaling
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 Scaling, from an IT resource perspective,
represents the ability of the IT resource to handle
increased or decreased usage demands.
 The following are types of scaling:
 Horizontal Scaling – scaling out and scaling in
 Vertical Scaling – scaling up and scaling down

Horizontal Scaling
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Figure 1.4
An IT resource (Virtual Server A) is scaled out by adding more of the same
IT resources (Virtual Servers B and C).

Vertical Scaling
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Figure 1.5
An IT resource (a virtual server with two CPUs) is scaled up by
replacing it with a more powerful IT resource with increased capacity
for data storage (a physical server with four CPUs).

HS & VS comparison
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Service
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 From an implementation perspective, a service is
a software program that can be remotely invoked
via a published technical interface (or API)
referred to as a service contract.
 When a software program invoked and interacts
with a service, it is labeled as a service
consumer.
 Services acting as service consumers can invoke
other services. When two or more services
participates to complete a given task, the services
form a service composition.
 A service can reside on-premise or in a cloud. In
the latter case, I is further qualified as a cloud
service (as explained in the following Cloud
Service section).

Cloud Service
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 A cloud service is any IT resource that is made
remotely accessible via a cloud.
 Unlike other IT fields that fall under the service
technology umbrella—such as service- oriented
architecture—the term ―service‖ within the context
of cloud computing is especially broad.

A cloud service that exists as a virtual server is also being accessed from
outside of the cloud’s boundary (right). The cloud service on the right may
be accessed by a human user that has remotely logged on to the virtual
server.
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A cloud service with a published technical interface is being accessed by
a consumer outside of the cloud (left). The cloud service on the left is
likely being invoked by a consumer program that was designed to access
the cloud service’s published technical interface.
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Goals and Benefits from Cloud
Computing
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Benefits
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 Reduced Investments and Proportional Costs
 Increased Scalability
 Increased Availability and Reliability

Reduced Investments and
Proportional Costs
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 The most common economic rationale for investing in
cloud-based IT resources is in the reduction or
outright elimination of up-front IT investments, namely
hardware and software purchases and ownership
costs.
 A cloud’s Measured Usage characteristic represents a
feature-set that allows measured operational
expenditures (directly related to business
performance) to replace anticipated capital
expenditures. This is also referred to as proportional
costs.

Proportional Costs
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 The Elimination or minimization of up-front
financial commitments allows enterprises to start
small and accordingly increase IT resource
allocation as required. Moreover, the reduction of
up-front capital expenses allows for the capital to
be redirected to the core business investment.
 IT professionals, and network bandwidth can be
obtained at lower costs, resulting in both

Proportional Costs
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 Common measurable benefits to cloud
consumers include:
 On-demand access to pay-as-you-go computing
resources on a short-term basis (such as
processors by the hour), and the ability to release
these computing resources when they are no longer
needed.
 The perception of having unlimited computing
resources that are available on demand, thereby
reducing the need to prepare for provisioning.
 The ability to add or remove IT resources at a fine-
grained level, such as modifying available storage
disk space by single gigabyte increments.
 Abstraction of the infrastructure so applications are not
locked into devices or locations and can be easily
moved if needed.

Increased Scalability
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 A simple example of usage demand fluctuations throughout a 24
hour period is provided in Figure 3.8.
Figure 1.8
An example of an organization’s changing demand for an IT
resource over the course of a day.

Increased Availability and Reliability
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 The availability and reliability of IT resources are
directly associated with tangible business
benefits.
 A hallmark of the typical cloud environment is its
intrinsic ability to provide extensive support for
increasing the availability of a cloud-based IT
resource to minimize or even eliminate outages,
and for increasing its reliability so as to minimize
the impact of runtime failure conditions.

Increased Availability and Reliability
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Specifically:
 An IT resource with increased availability is
accessible for longer periods of time (for example,
22 hours out of a 24 hour day). Cloud providers
generally offer resilient‖ IT resources for which
they are able to guarantee high levels of
availability.
 An IT resource with increased reliability is able to
better avoid and recover from exception
conditions. The modular architecture of cloud
environments provides extensive failover support
that increases reliability.

Risks and Challenges
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Risks and Challenges
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 Increased Security Vulnerabilities
 Reduced Operational Governance Control
 Limited Portability Between Cloud Providers
 Multi-Regional Compliance and Legal Issue

Increased Security Vulnerabilities
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 The moving of business data to the cloud means
that the responsibility over data security becomes
shared with the cloud provider. The remote usage
of IT resources requires an expansion of trust
boundaries by the cloud consumer to include the
external cloud.

Consider the following examples:
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 An unreliable cloud provider may not maintain
the guarantees it makes in the SLAs that were
published for its cloud services. This can
jeopardize the quality of the cloud consumer
solutions that rely on these cloud services.
 Longer geographic distances between the
cloud consumer and cloud provider can
require additional network hops that introduce
fluctuating latency and potential bandwidth
constraints.

Figure 1.10
An unreliable network connection compromises the quality of
communication between cloud consumer and cloud provider
environments. 3/17/201456

Limited Portability Between Cloud
Providers
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 Due to a lack of established industry
standards within the cloud computing industry,
public clouds are commonly proprietary to
various extents. For cloud consumers that
have custom-built solutions with
dependencies on these proprietary
environments, it can be challenging to move
from one cloud provider to another.
 Portability is a measure used to determine the
impact of moving cloud consumer IT
resources and data between clouds

Figure 1.11
A cloud consumer’s application has a decreased level of portability when assessing a potential migration from
Cloud A to Cloud B, because the cloud provider of Cloud B does not support the same security technologies
as Cloud A.
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Multi-Regional Compliance and
Legal Issues
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 Third-party cloud providers will frequently establish
data centers in affordable or convenient geographical
locations. Cloud consumers will often not be aware of
the physical location of their IT resources and data
when hosted by public clouds.
 For some organizations, this can pose serious legal
concerns pertaining to industry or government
regulations that specify data privacy and storage
policies.
 For example, some UK laws require personal data
belonging to UK citizens to be kept within the United
Kingdom.

Legal Issues
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 Another potential legal issue pertains to the
accessibility and disclosure of data.
 Countries have laws that require some types of data
to be disclosed to certain government agencies or to
the subject of the data.
 For example, a European cloud consumer’s data that
is located in the U.S. can be more easily accessed by
government agencies (due to the U.S. Patriot Act)
when compared to data located in many European
Union countries.

Fundamental cloud computing

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