Introduction to Cloud Computing and Cloud Infrastructure

Introduction to Cloud Computing and
Cloud Infrastructure
Mr. Santhosh Kumar K L
Assistant Professor, Department of CSE (PG)
Nitte Meenakshi Institute of Technology (NMIT), Bangalore
Email: santhosh.kumar.kadur@gmail.com
Contents
 Cloud Computing
 Delivery models and services
 Ethical issues
 Cloud vulnerabilities
 Cloud computing at Amazon
 Cloud computing the Google perspective
 Microsoft Windows Azure and online services
 Open-source software platforms for private clouds
1

 The last decades have reinforced the idea that information processing can
be done more efficiently centrally, on large farms of computing and
storage systems accessible via the Internet.
 When computing resources in distant data centers are used rather than
local computing systems, we talk about network-centric computing and
network-centric content.
 Advancements in networking and other areas are responsible for the
acceptance of the two new computing models and led to the grid
computing movement in the early 1990s and, since 2005, to utility
computing and cloud computing.
Introduction

 Cloud computing delivery models, deployment models, defining attributes,
resources, and organization of the infrastructure as shown in Figure 1.1.
There are three cloud delivery models: Software-as-a-Service (SaaS),
Platform-as-a-Service (PaaS), and Infrastructure-as-a-Service (IaaS),
deployed as public, private, community, and hybrid clouds.
 In utility computing the hardware and software resources are
concentrated in large data centers and users can pay as they consume
computing, storage, and communication resources. Utility computing often
requires a cloud-like infrastructure, but its focus is on the business model
for providing the computing services.
 Cloud computing is a path to utility computing embraced by major IT
companies such as Amazon, Apple, Google, HP, IBM, Microsoft, Oracle, and
others.
Introduction (cont..)

Fig 1. Cloud computing: Delivery models, deployment models, defining attributes,
resources, and organization of the infrastructure.

The defining attributes of the new philosophy for delivering computing services
are as follows:
 Cloud computing uses Internet technologies to offer elastic services. The
term elastic computing refers to the ability to dynamically acquire
computing resources and support a variable workload. A cloud service
provider maintains a massive infrastructure to support elastic services.
 The resources used for these services can be metered and the users can be
charged only for the resources they use.
 Maintenance and security are ensured by service providers.
 Economy of scale allows service providers to operate more efficiently due
to specialization and centralization.
 Cloud computing is cost-effective due to resource multiplexing; lower
costs for the service provider are passed on to the cloud users.
 The application data is stored closer to the site where it is used in a device-
and location-independent manner; potentially, this data storage strategy
increases reliability and security and, at the same time, it lowers
communication costs.

 Cloud computing is a technical and social reality and an emerging technology.
At this time, one can only speculate how the infrastructure for this new
paradigm will evolve and what applications will migrate to it.
 Scientific and engineering applications, data mining, computational
financing, gaming, and social networking as well as many other
computational and data-intensive activities can benefit from cloud
computing. A broad range of data, from the results of high-energy physics
experiments to financial or enterprise management data to personal data
such as photos, videos, and movies, can be stored on the cloud.
 In early 2011 Apple announced the iCloud, a network-centric alternative for
storing content such as music, videos, movies, and personal information; this
content was previously confined to personal devices such as workstations,
laptops, tablets, or smartphones.

 In the next few years, the focus of cloud computing is expected to shift from
building the infrastructure, today’s main front of competition among the
vendors, to the application domain. This shift in focus is reflected by Google’s
strategy to build a dedicated cloud for government organizations in the
United States.

Cloud computing: an old idea whose time has come
 The term computer cloud is overloaded, since it covers infrastructures of
different sizes, with different management and different user populations.
Several types of cloud are envisioned:
o Private cloud. The infrastructure is operated solely for an organization. It may be
managed by the organization or a third party and may exist on or off the premises of
the organization.
o Community cloud. The infrastructure is shared by several organizations and supports
a specific community that has shared concerns (e.g., mission, security requirements,
policy, and compliance considerations). It may be managed by the organizations or a
third party and may exist on premises or off premises.
o Public cloud. The infrastructure is made available to the general public or a large
industry group and is owned by an organization selling cloud services.
o Hybrid cloud. The infrastructure is a composition of two or more clouds (private,
community, or public) that remain unique entities but are bound together by
standardized or proprietary technology that enables data and application portability.

A nonexhaustive list of reasons for the success of cloud computing includes these points:
 Cloud computing is in a better position to exploit recent advances in software,
networking, storage, and processor technologies. Cloud computing is promoted by
large IT companies where these new technological developments take place, and
these companies have a vested interest in promoting the new technologies.
 A cloud consists of a homogeneous set of hardware and software resources in a
single administrative domain. In this setup, security, resource management, fault
tolerance, and quality of service are less challenging than in a heterogeneous
environment with resources in multiple administrative domains.
 Cloud computing is focused on enterprise computing; its adoption by industrial
organizations, financial institutions, healthcare organizations, and so on has a
potentially huge impact on the economy.
Cloud computing: an old idea whose time has come (cont..)

 A cloud provides the illusion of infinite computing resources; its elasticity frees
application designers from the confinement of a single system.
 A cloud eliminates the need for up-front financial commitment, and it is based on a
pay-as-you-go approach. This has the potential to attract new applications and new
users for existing applications, fomenting a new era of industrywide technological
advancements.

o Availability of service. What happens when the service provider cannot deliver? Can
a large company such as General Motors move its IT to the cloud and have assurances
that its activity will not be negatively affected by cloud overload? A partial answer to
this question is provided by service-level agreements (SLAs). A temporary fix with
negative economical implications is overprovisioning, that is, having enough resources
to satisfy the largest projected demand.
o Vendor lock-in. Once a customer is hooked to one provider, it is hard to move to
another. The standardization efforts at National Institute of Standards and Technology
(NIST) attempt to address this problem.
o Data confidentiality and auditability.
o Data transfer bottlenecks. Many applications are data-intensive. A very important
strategy is to store the data as close as possible to the site where it is needed.
In spite of the technological breakthroughs that have made cloud computing feasible,
there are still major obstacles for this new technology; these obstacles provide
opportunity for research. A few of the most obvious obstacles:

o Performance unpredictability. This is one of the consequences of resource sharing.
Strategies for performance isolation.
o Elasticity, the ability to scale up and down quickly. New algorithms for controlling
resource allocation and workload placement are necessary. Autonomic computing
based on self-organization and self management seems to be a promising avenue.

Cloud computing delivery models and services
 According to the NIST reference model in Figure 1.2, the entities involve in cloud
computing are as follows:
• Service consumer, the entity that maintains a business relationship with and
uses service from service providers;
• Service provider, the entity responsible for making a service available to
service consumers;
• Carrier, the intermediary that provides connectivity and transport of cloud
services between providers and consumers;
• Broker, an entity that manages the use, performance, and delivery of cloud
services and negotiates relationships between providers and consumers;
• Auditor, a party that can conduct independent assessment of cloud services,
information system operations, performance, and security of the cloud
implementation. An audit is a systematic evaluation of a cloud system that
measures how well it conforms to a set of established criteria.

Fig 1.2 The entities involved in service-oriented computing and, in particular, in cloud
computing, according to NIST.
The carrier provides connectivity among service providers, service consumers, brokers, and
auditors.
Cloud computing delivery models and services (cont..)

Fig 1.3 The structure of the three delivery models, SaaS, PaaS, and IaaS.

Figure 1.3 presents the structure of the three delivery models, SaaS, PaaS, and IaaS,
according to the Cloud Security Alliance.
Software-as-a-Service (SaaS)
 SaaS gives the capability to use applications supplied by the service provider in 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).
 The user 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. Services offered include:
• Enterprise services such as workflow management, groupware and collaborative,
supply chain, communications, digital signature, customer relationship management
(CRM), desktop software, financial management, geo-spatial, and search.
• Web 2.0 applications such as metadata management, social networking, blogs, wiki
services, and portal services.

 The SaaS is not suitable for applications that require real-time response or those for
which data is not allowed to be hosted externally. The most likely candidates for SaaS
are applications for which:
• Many competitors use the same product, such as email.
• Periodically there is a significant peak in demand, such as billing and payroll.
• There is a need for Web or mobile access, such as mobile sales management
software.
• There is only a short-term need, such as collaborative software for a project.

Platform-as-a-Service (PaaS)
 PaaS gives the capability to deploy consumer-created or acquired applications using
programming languages and tools supported by the provider.
 The user does not manage or control the underlying cloud infrastructure, including
network, servers, operating systems, or storage. The user has control over the
deployed applications and, possibly, over the application hosting environment
configurations.
 Such services include session management, device integration, sandboxes,
instrumentation and testing, contents management, knowledge management, and
Universal Description, Discovery, and Integration (UDDI), a platform-independent
Extensible Markup Language (XML)-based registry providing a mechanism to
register and locate Web service applications.

 PaaS is not particularly useful when the application must be portable, when
proprietary programming languages are used, or when the underlaying hardware
and software must be customized to improve the performance of the application.
 The major PaaS application areas are in software development where multiple
developers and users collaborate and the deployment and testing services should
be automated.

Infrastructure-as-a-Service(IaaS)
 Infrastructure-as-a-Service (IaaS) is the capability to provision processing, storage,
networks, and other fundamental computing resources; the consumer is able to
deploy and run arbitrary software, which can include operating systems and
applications.
 The IaaS cloud computing delivery model has a number of characteristics, such as
the fact that the resources are distributed and support dynamic scaling, it is based
on a utility pricing model and variable cost, and the hardware is shared among
multiple users.

A number of activities are necessary to support the three delivery models; they include:
1. Service management and provisioning, including virtualization, service provisioning,
call center, operations management, systems management, QoS management, billing
and accounting, asset management, SLA management, technical support, and
backups.
2. Security management, including ID and authentication, certification and
accreditation, intrusion prevention, intrusion detection, virus protection,
cryptography, physical security, incident response, access control, audit and trails,
and firewalls.
3. Customer services such as customer assistance and online help, subscriptions,
business intelligence, reporting, customer preferences, and personalization.
4. Integration services, including data management and development.

Ethical issues in cloud computing
 Cloud computing is based on a paradigm shift with profound implications for
computing ethics. The main elements of this shift are:
(i) the control is relinquished to third-party services;
(ii) the data is stored on multiple sites administered by several organizations;
(iii) multiple services interoperate across the network.
 Unauthorized access, data corruption, infrastructure failure, and service
unavailability are some of the risks related to relinquishing the control to third-party
services; moreover, whenever a problem occurs, it is difficult to identify the source
and the entity causing it. Systems can span the boundaries of multiple organizations
and cross security borders, a process called deperimeterization.
 The complex structure of cloud services can make it difficult to determine who is
responsible in case something undesirable happens. In a complex chain of events or
systems, many entities contribute to an action, with undesirable consequences.

 Ubiquitous and unlimited data sharing and storage among organizations test the self-
determination of information, the right or ability of individuals to exercise personal
control over the collection, and use and disclosure of their personal data by others;
this tests the confidence and trust in today’s evolving information society.
Ethical issues in cloud computing (cont..)
 Cloud service providers have already collected petabytes of sensitive personal
information stored in data centers around the world. The acceptance of cloud
computing therefore will be determined by privacy issues addressed by these
companies and the countries where the data centers are located.

 The need for rules and regulations for the governance of cloud computing is
obvious. The term governance means the manner in which something is governed
or regulated, the method of management, or the system of regulations.
 Accountability is a necessary ingredient of cloud computing; adequate information
about how data is handled within the cloud and about allocation of responsibility are
key elements for enforcing ethics rules in cloud computing.
 Unwanted dependency on a cloud service provider, the so-called vendor lock-in, is a
serious concern, and the current standardization efforts at NIST attempt to address
this problem. Another concern for users is a future with only a handful of companies
that dominate the market and dictate prices and policies.
Ethical issues in cloud computing (cont..)

 Clouds are affected by malicious attacks and failures of the infrastructure (e.g., power
failures). Such events can affect Internet domain name servers and prevent access to
a cloud or can directly affect the clouds.
For example:
• An attack at Akamai on June 15, 2004 caused a domain name outage and a major
blackout that affected Google, Yahoo!, and many other sites.
• In May 2009 Google was the target of a serious denial-of-service (DoS) attack
that took down services such Google News and Gmail for several days.
• Lightning caused a prolonged downtime at Amazon on June 29 and 30, 2012
Cloud vulnerabilities
 The recovery from the failure will take a very long time and exposes a range of
problems.
For example:
• one of the 10 centers failed to switch to backup generators before exhausting the
power that could be supplied by uninterruptible power supply (UPS) units.

 Clustering the resources in data centers located in different geographical areas is
one of the means used today to lower the probability of catastrophic failures. This
geographic dispersion of resources could have additional positive side effects; it can
reduce communication traffic and energy costs by dispatching the computations to
sites where the electric energy is cheaper, and it can improve performance by an
intelligent and efficient load-balancing strategy.
Cloud vulnerabilities (cont..)
 The price to pay for any system optimization is increased system complexity.
For example,
• the latency of communication over a wide area network (WAN) is considerably
larger than the one over a local area network (LAN) and requires the
development of new algorithms for global decision making.

Cloud Infrastructure
 The major cloud computing infrastructure are Amazon, Google and Microsoft.
These cloud service providers support one or more of the three cloud computing
delivery models : Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS),
and Software-as-a-Service (SaaS).
 Private clouds are an alternative to public clouds. Open-source cloud computing
platforms such as Eucalyptus, OpenNebula, Nimbus, and OpenStack can be used
as a control infrastructure for a private cloud.
 Amazon is a pioneer in IaaS, Google’s efforts are focused on SaaS and PaaS delivery
models, and Microsoft is involved in PaaS.
 Several other IT companies are also involved in cloud computing. IBM offers a cloud
computing platform, IBMSmartCloud, which includes servers, storage, and
virtualization components for building private and hybrid cloud computing
environments.

 In 2011 HP announced plans to enter the cloud computing club.
Cloud Infrastructure (cont..)
 Oracle announced its entry to enterprise computing in the early 2012. The Oracle
Cloud is based on Java, SQL standards, and software systems such as Exadata,
Exalogic, WebLogic, and Oracle Database.

Cloud computing at Amazon
 Amazon introduced a computing platform that has changed the face of computing in
the last decade. First, it installed a powerful computing infrastructure to sustain its
core business, e-commerce, selling a variety of goods ranging from books and CDs to
gourmet foods and home appliances. Then Amazon discovered that this
infrastructure could be further extended to provide affordable and easy-to-use
resources for enterprise computing as well as computing for the masses.
 In mid-2000 Amazon introduced Amazon Web Services (AWS), based on the IaaS
delivery model. In this model the cloud service provider offers an infrastructure
consisting of compute and storage servers interconnected by high-speed networks
that support a set of services to access these resources. An application developer is
responsible for installing applications on a platform of his or her choice and
managing the resources provided by Amazon.

 It is reported that in 2012, businesses in 200 countries used the AWS, demonstrating
the international appeal of this computing paradigm. A significant number of large
corporations as well as start-ups take advantage of computing services supported by
the AWS infrastructure.
Amazon Web Services
 Amazon was the first provider of cloud computing; it announced a limited public
beta release of its Elastic Computing platform called EC2 in August 2006. Figure 1
shows the palette of AWS services accessible via the Management Console in late
2011
o Elastic Compute Cloud (EC2) is a Web service with a simple interface for launching
instances of an application under several operating systems, such as several Linux
distributions, Microsoft Windows Server 2003 and 2008, OpenSolaris, FreeBSD, and
NetBSD.
Cloud computing at Amazon (cont..)

Fig 1: Services offered by AWS are
accessible from the AWS
Management Console. Applications
running under a variety of operating
systems can be launched using EC2.
Multiple EC2 instances can
communicate using SQS. Several
storage services are available: S3,
Simple DB, and EBS. The Cloud Watch
supports performance monitoring;
the Auto Scaling supports elastic
resource management. The Virtual
Private Cloud allows direct migration
of parallel applications.
Amazon Web Services (cont..)

o An instance is created either from a predefined Amazon Machine Image (AMI)
digitally signed and stored in S3 or from a user-defined image. The image includes the
operating system, the run-time environment, the libraries, and the application desired
by the user. AMI images create an exact copy of the original image but without
configuration-dependent information such as the hostname or the MAC address.
o EC2 is based on the Xen virtualization strategy. In EC2 each virtual machine or
instance functions as a virtual private server.
Elastic Compute Cloud (EC2) (cont..)
o A user can:
(i) Launch an instance from an existing AMI and terminate an instance;
(ii) start and stop an instance;
(iii) create a new image;
(iv) add tags to identify an image; and
(v) reboot an instance.

o EC2 allows the import of virtual machine images from the user environment to an
instance through a facility called VM import. It also automatically distributes the
incoming application traffic among multiple instances using the elastic load-
balancing facility.
o EC2 associates an elastic IP address with an account; this mechanism allows a user to
mask the failure of an instance and remap a public IP address to any instance of the
account without the need to interact with the software support team.
Elastic Compute Cloud (EC2) (cont..)

o Simple Storage System (S3) is a storage service designed to store large objects. It
supports a minimal set of functions: write, read, and delete.
o S3 allows an application to handle an unlimited number of objects ranging in size from
one byte to five terabytes. An object is stored in a bucket and retrieved via a unique
developer-assigned key.
o S3 supports PUT, GET, and DELETE primitives to manipulate objects but does not
support primitives to copy, rename, or move an object from one bucket to another.
o S3 computes the MD (Message-Digest Algorithm) of every object written and returns it
in a field called ETag. A user is expected to compute the MD5 of an object stored or
written and compare this with the ETag; if the two values do not match, then the object
was corrupted during transmission or storage.
o The Amazon S3 SLA guarantees reliability. S3 uses standards-based REST
(Representational State Transfer) and SOAP (Simple Object Access Protocol)
interfaces; the default download protocol is HTTP, but BitTorrent protocol interface is
also provided to lower costs for high-scale distribution.

o Elastic Block Store (EBS) provides persistent block-level storage volumes for use
with Amazon EC2 instances. A volume appears to an application as a raw,
unformatted, and reliable physical disk; the size of the storage volumes ranges from
one gigabyte to one terabyte. The volumes are grouped together in availability zones
and are automatically replicated in each zone.
o Simple DB is a non-relational data store that allows developers to store and query
data items via Web services requests. It supports store-and-query functions
traditionally provided only by relational databases.
 Simple DB creates multiple geographically distributed copies of each data item
and supports high-performance Web applications; at the same time, it
automatically manages infrastructure provisioning, hardware and software
maintenance, replication and indexing of data items, and performance tuning.

o Simple Queue Service (SQS) is a hosted message queue. SQS is a system for
supporting automated workflows; it allows multiple Amazon EC2 instances to
coordinate their activities by sending and receiving SQS messages. Any computer
connected to the Internet can add or read messages without any installed software or
special firewall configurations.
o Virtual Private Cloud (VPC) provides a bridge between the existing IT infrastructure
of an organization and the AWS cloud. The existing infrastructure is connected via a
virtual private network (VPN) to a set of isolated AWS compute resources. VPC allows
existing management capabilities such as security services, firewalls, and intrusion
detection systems to operate seamlessly within the cloud.
o Auto Scaling exploits cloud elasticity and provides automatic scaling of EC2 instances.
The service supports grouping of instances, monitoring of the instances in a group, and
defining triggers and pairs of CloudWatch alarms and policies, which allow the size of
the group to be scaled up or down. Typically, a maximum, a minimum, and a regular
size for the group are specified.

 Several new AWS services were introduced in 2012; Among the new services we
note:
• Route 53, a low-latency DNS service used to manage user’s DNS public records;
• Elastic MapReduce (EMR), a service supporting processing of large amounts of data
using a hosted Hadoop running on EC2 and based on the MapReduce paradigm;
• Simple Workflow Service (SWF), which supports workflow management and allows
scheduling, management of dependencies, and coordination of multiple EC2
instances;
• ElastiCache, a service enabling Web applications to retrieve data from a managed in-
memory caching system rather than a much slower disk-based database;
• DynamoDB, a scalable and low-latency fully managed NoSQL database service;
• CloudFront, a Web service for content delivery; and Elastic Load Balancer, a cloud
service to automatically distribute the incoming requests across multiple instances
of the application.

 Two new services, the Elastic Beanstalk and the CloudFormation,
Elastic Beanstalk
 Elastic Beanstalk, a service that interacts with other AWS services, including EC2, S3,
SNS, Elastic Load Balance, and Auto Scaling, automatically handles the deployment,
capacity provisioning, load balancing, Auto Scaling, and application monitoring
functions.
 The service automatically scales the resources as required by the application, either
up, or down based on default Auto Scaling settings.
 Some of the management functions provided by the service are:
(i) deployment of a new application version (or rollback to a previous version);
(ii) access to the results reported by CloudWatch monitoring service;
(iii) email notifications when application status changes or application servers are
added or removed; and
(iv) access to server login files without needing to login to the application servers.
 The Elastic Beanstalk service is available to developers using a Java platform, the PHP
server-side description language, or .NET framework.

CloudFormation
 CloudFormation allows the
creation of a stack describing the
infrastructure for an application.
The user creates a template, a
text file formatted as in Javascript
Object Notation (JSON),
describing the resources, the
configuration values, and the
interconnection among these
resources.
 The template can be
parameterized to allow
customization at run time. A
template for the creation of an
EC2 instance follows:

 The Amazon Web Services Licensing Agreement (AWSLA) allows the cloud service
provider to terminate service to any customer at any time for any reason and contains
a covenant not to sue Amazon or its affiliates for any damages that might arise out of
the use of AWS.
 Users have several choices for interacting with and managing AWS resources from
either a Web browser or from a system running Linux or Microsoft Windows:
1. The AWSWebManagement Console, available at http://aws.amazon.com/console/;
this is the easiest way to access all services, but not all options may be available in this
mode.
2. Command-line tools; see http://aws.amazon.com/developertools.
3. AWS SDK libraries and toolkits provided for several programming languages,
including Java, PHP, C#, and Obj C.
4. Raw REST requests.

Regions and Availability Zones.
 Today Amazon offers cloud services through a network of data centers on several
continents (see Table 1). In each region there are several availability zones
interconnected by high-speed networks; regions communicate through the Internet
and do not share resources.

 An availability zone is a data center consisting of a large number of servers. A server
may run multiple virtual machines or instances, started by one or more users; an
instance may use storage services, S3, EBS), and Simple DB, as well as other services
provided by AWS (see Figure 2).
Fig 2: The configuration of an availability zone supporting AWS service.

 Storage is automatically replicated within a region; S3 buckets are replicated within an
availability zone and between the availability zones of a region, whereas EBS volumes
are replicated only within the same availability zone.
 A user can request virtual servers and storage located in one of the regions. The user
can also request virtual servers in one of the availability zones of that region. The
Elastic Compute Cloud (EC2) service allows a user to interact and to manage the virtual
servers.
 The billing rates in each region are determined by the components of the operating
costs, including energy, communication, and maintenance costs. Thus, the choice of
the region is motivated by the desire to minimize costs, reduce communication
latency, and increase reliability and security.

 When launched, an instance is provided with a DNS name. This name maps to a
private IP address for internal communication within the internal EC2
communication network and a public IP address for communication outside the
internal Amazon network, (e.g., for communication with the user that launched the
instance).Network Address Translation (NAT) maps external IP addresses to internal
ones.
 The public IP address is assigned for the lifetime of an instance and it is returned to
the pool of available public IP addresses when the instance is either stopped or
terminated. An instance can request an elastic IP address, rather than a public IP
address.

The Charges for Amazon Web Services.
 Amazon charges a fee for EC2 instances, EBS storage, data transfer, and several other
services. The charges differ from one region to another and depend on the pricing
model; see http://aws.amazon.com/ec2/pricing for the current pricing structure.
 There are three pricing models for EC2 instances: on-demand, reserved, and spot.
• On-demand instances use a flat hourly rate, and the user is charged for the time
an instance is running; no reservation is required for this most popular model.
• For reserved instances a user pays a one-time fee to lock in a typically lower
hourly rate. This model is advantageous when a user anticipates that the
application will require a substantial number of CPU cycles and this amount is
known in advance. Additional capacity is available at the larger standard rate.
• In case of spot instances, users bid on unused capacity and their instances are
launched when the market price reaches a threshold specified by the user.

 The EC2 system offers several instance types:
• Standard instances. Micro (StdM), small (StdS), large (StdL), extra large (StdXL);
small is the default.
• High memory instances. High-memory extra-large (HmXL), high-memory double
extra-large (Hm2XL), and high-memory quadruple extra-large (Hm4XL).
• High CPU instances. High-CPU extra-large (HcpuXL).
• Cluster computing. Cluster computing quadruple extra-large (Cl4XL).
 Table 2 summarizes the features and the amount of resources supported by each
instance. The resources supported by each configuration are main memory, virtual
computers (VCs) with a 32- or 64-bit architecture, instance memory (I-memory) on
persistent storage, and I/O performance at two levels: moderate (M) or high (H).
The computing power of a virtual core is measured in EC2 compute units (CUs).

 A main attraction of Amazon cloud computing is the low cost. The dollar amounts
charged for one hour of running Amazon’s services under Linux or Unix and
Microsoft Windows in mid-2012 are summarized in Table 3.
 There are no charges for data transfers from the user’s site to the Amazon network
or within the Amazon network; the charges for data transfer from the AWS network
to the outside world depend on the region. For example, the charges for the US West
(Oregon) region are shown in Table 4.
An Evaluation of Amazon Web Services.
 In 2007 Garfinkel reported the results of an early evaluation of Amazon Web
Services. The paper reports that EC2 instances are fast, responsive, and very reliable;
a new instance could be started in less than two minutes.
 During the year of testing, one unscheduled reboot and one instance freeze were
experienced. No data was lost during the reboot, but no data could be recovered
from the virtual disks of the frozen instance.

Cloud computing: the Google perspective
 Google’s effort is concentrated in the area of Software-as-a-Service (SaaS). Services
such as Gmail, Google Drive, Google Calendar, Picasa, and Google Groups are free
of charge for individual users and available for a fee for organizations. These services
are running on a cloud and can be invoked from a broad spectrum of devices,
including mobile ones such as iPhones, iPads, Black-Berrys, and laptops and tablets.
The data for these services is stored in data centers on the cloud.
 The Gmail service hosts emails on Google servers and, provides aWeb interface to
access them and tools for migrating from Lotus Notes and Microsoft Exchange.
 Google Docs is Web-based software for building text documents, spreadsheets, and
presentations.
 Google Calendar is a browser-based scheduler; it supports multiple calendars for a
user, the ability to share a calendar with other users, the display of daily/ weekly/
monthly views, and the ability to search events and synchronize with the Outlook
Calendar.

 Picasa is a tool to upload, share, and edit images; it provides 1 GB of disk space per
user free of charge. Users can add tags to images and attach locations to photos using
Google Maps.
 Google is also a leader in the Platform-as-a-Service (PaaS) space. AppEngine is a
developer platform hosted on the cloud. Initially it supported only Python, but support
for Java was added later and detailed documentation for Java is available. The database
for code development can be accessed with Google Query Language (GQL) with a SQL-
like syntax.
 Search engine crawlers rely on hyperlinks to discover new content. The deep Web is
content stored in databases and served as pages created dynamically by querying
HTML forms.
 Examples of deep Web sources are sites with geographic-specific information, such
as local stores, services, and businesses; sites that report statistics and analysis
produced by governmental and nongovernmental organizations; art collections;
photo galleries; bus, train, and airline schedules; and so on.
Cloud computing: the Google perspective (cont..)

 Structured content is created by labelling; Flickr and Google Co-op are examples of
structures where labels and annotations are added to objects, images, and pages
stored on the Web.
 Google Co-op allows users to create customized search engines based on a set of facets
or categories.
 Google Base is a service allowing users to load structured data from different sources
to a central repository that is a very large, self-describing, semi-structured,
heterogeneous database. It is self describing because each item follows a simple
schema: (item type, attribute names).
 Google Drive is an online service for data storage that has been available since April
2012. It gives users 5 GB of free storage and charges $4 per month for 20 GB.

 Google has also redefined the laptop with the introduction of the Chromebook, a
purely Web-centric device running Chrome OS. Cloud-based applications, extreme
portability, built-in 3G connectivity, almost instant-on, and all-day battery life are the
main attractions of this device with a keyboard.
 Google as well as the other cloud service providers must manage vast amounts of
data. In a world where users would most likely desire to use multiple cloud services
from independent providers, the question of whether the traditional data base
management services (DBMSs) are sufficient to ensure interoperability comes to
mind.

Microsoft Windows Azure and Online Services
 Azure and Online Services are, respectively, PaaS and SaaS cloud platforms from
Microsoft. Windows Azure is an operating system, SQL Azure is a cloud-based
version of the SQLServer, and AzureAppFabric (formerly .NET Services) is a
collection of services for cloud applications.
 Windows Azure has three core components (see Figure 3):
 Compute, which provides a computation environment;
 Storage for scalable storage; and
 Fabric Controller, which deploys, manages, and monitors applications; it
interconnects nodes consisting of servers, high-speed connections, and switches.
 The Content Delivery Network (CDN) maintains cache copies of data to speed up
computations. The Connect subsystem supports IP connections between the users and
their applications running on Windows Azure. The API interface to Windows Azure is
built on REST, HTTP, and XML. The platform includes five services: Live Services, SQL
Azure, AppFabric, SharePoint, and Dynamics CRM. A client library and tools are also
provided for developing cloud applications in Visual Studio.

Microsoft Windows Azure and Online Services (cont..)

 The computations carried out by an application are implemented as one or more roles;
an application typically runs multiple instances of a role. We can distinguish
(i)Web role instances used to createWeb applications;
(ii) Worker role instances used to run Windows-based code; and
(iii) VM role instances that run a user-provided Windows Server 2008 R2 image.
 Scaling, load balancing, memory management, and reliability are ensured by a fabric
controller, a distributed application replicated across a group of machines that owns
all of the resources in its environment – computers, switches, load balancers – and it
is aware of every Windows Azure application.
• The fabric controller decides where new applications should run; it chooses the
physical servers to optimize utilization using configuration information
uploaded with each Windows Azure application.

 Blobs, tables, queues, and drives are used as scalable storage. A blob contains binary
data; a container consists of one or more blobs.
• Blobs can be up to a terabyte and they may have associated metadata (e.g., the
information about where a JPEG photograph was taken).
• Blobs allow a Windows Azure role instance to interact with persistent storage as
though it were a local NTFS (New Technology File System file system).
 The Microsoft Azure platform currently does not provide or support any
distributed parallel computing frameworks, such as MapReduce, Dryad, or MPI,
other than the support for implementing basic queue-based job scheduling.

Open-Source Software Platforms for Private Clouds
 Private clouds provide a cost-effective alternative for very large organizations. A
private cloud has essentially the same structural components as a commercial one: the
servers, the network, virtual machines monitors (VMMs) running on individual
systems, an archive containing disk images of virtual machines (VMs), a front end for
communication with the user, and a cloud control infrastructure.
 Open-source cloud computing platforms such as Eucalyptus, OpenNebula, and Nimbus
can be used as a control infrastructure for a private cloud.
 Schematically, a cloud infrastructure carries out the following steps to run an
application:
• Retrieves the user input from the front end.
• Retrieves the disk image of a VM from a repository.
• Locates a system and requests the VMM running on that system to set up a VM.
• Invokes the DHCP (Dynamic Host Configuration Protocol) and the IP bridging
software to set up a MAC and IP address for the VM.

 Eucalyptus (www.eucalyptus.com) can be regarded as an open-source counterpart of
Amazon’s EC2. The systems supports several operating systems including CentOS 5
and 6, RHEL 5 and 6, Ubuntu 10.04 LTS, and 12.04 LTS.
 The major three open-source software systems are Eucalyptus, OpenNebula, and
Nimbus.
Open-Source Software Platforms for Private Clouds (cont..)
 The components of the system are:
 Virtual machine. Runs under several VMMs, including Xen, KVM, and Vmware.
 Node controller. Runs on every server or node designated to host a VM and controls the
activities of the node. Reports to a cluster controller.
 Cluster controller. Controls a number of servers. Interacts with the node controller on
each server to schedule requests on that node. Cluster controllers are managed by the
cloud controller.
 Cloud controller. Provides the cloud access to end users, developers, and
administrators. It is accessible through command-line tools compatible with EC2and
through a Web-based Dashboard. Manages cloud resources, makes high-level scheduling
decisions, and interacts with cluster controllers.

• Storage controller. Provides persistent virtual hard drives to applications. It is the
correspondent of EBS. Users can create snapshots from EBS volumes. Snapshots are
stored in Walrus and made available across availability zones.
• Storage service (Walrus). Provides persistent storage and, similarly to S3, allows
users to store objects in buckets.
The components of the Eucalyptus system (cont…)

 Open-Nebula (www.opennebula.org) is a private cloud with users actually logging into
the head node to access cloud functions. The system is centralized and its default
configuration uses NFS (Network File System).
 The procedure to construct a virtual machine consists of several steps:
(i) the user signs into the head node using ssh;
(ii) the system uses the onevm command to request a VM;
(iii) the VM template disk image is transformed to fit the correct size and configuration
within the NFS directory on the head node;
(iv) the oned daemon on the head node uses ssh to log into a compute node;
(v) the compute node sets up network bridging to provide a virtual NIC with a virtual
MAC;
(vi) the files needed by the VMM are transferred to the compute node via the NFS;
(vii) the VMM on the compute node starts the VM; and
(viii) the user is able to ssh directly to the VM on the compute node.
 According to the analysis in the system is best suited for an operation involving a
small-to medium-sized group of trusted and knowledgeable users who are able to
configure this versatile system based on their needs.

 Nimbus (www.nimbusproject.org) is a cloud solution for scientific applications based
on the Globus software. The system inherits from Globus the image storage, the
credentials for user authentication, and the requirement that a running Nimbus
process can ssh into all compute nodes. Customization in this system can only be done
by the system administrators.
Table 5 summarizes the features of the three systems. The conclusions of the comparative
analysis are as follows: Eucalyptus is best suited for a large corporation with its own private
cloud because it ensures a degree of protection from user malice and mistakes. OpenNebula is
best suited for a testing environment with a few servers. Nimbus is more adequate for a
scientific community less interested in the technical internals of the system than with broad
customization requirements.

 OpenStack is an open-source project started in 2009 at the National Aeronautics and
Space Administration (NASA) in collaboration with Rackspace (www.rackspace.com)
to develop a scalable cloud operating system for farms of servers using standard
hardware.
 Though recently NASA has moved its cloud infrastructure to AWS in addition to
Rackspace, several other companies, including HP, Cisco, IBM, and Red Hat, have an
interest in OpenStack.
 The current version of the system supports a wide range of features such as
application programming interfaces (APIs) with rate limiting and authentication; live
VM management to run, reboot, suspend, and terminate instances; role-based access
control; and the ability to allocate, track, and limit resource utilization. The
administrators and the users control their resources using an extensible Web
application called the Dashboard.

REFERENCES
 Dan C Marinescu: “ Cloud Computing Theory and Practice.” Elsevier(MK)
2013.
 RajkumarBuyya, James Broberg, Andrzej Goscinski: “Cloud Computing
Principles and Paradigms”, Willey 2014.
 Kai Hwang, Geoffrey C Fox and Jack J Dongarra, “Distributed and cloud
computing”, Elsevier(MK) 2012.
 John W Ritting house, James F Ransome: “Cloud Computing Implementation,
Management and Security”, CRC Press 2013.

Introduction to Cloud Computing and Cloud Infrastructure

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