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BE - SEMESTER–VII (NEW)
EXAMINATION – WINTER 2021
Subject Code:3170717
Date:15/12/2021
Subject Name: Cloud Computing
Q.1
(a) Explain Challenges and Applications of Cloud computing. 03
(b) What are the advantages of Virtualization using in cloud computing? 04
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(c) Explain various layers of Cloud Computing. 07
1) SaaS (Software as a Service)
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SaaS or software as a service is a software distribution model in which applications
are hosted by a vendor or service provider and made available to customers over a
network (internet).
Through the internet this service is available to users anywhere in the world. instead
of purchasing the software, they subscribe to it, usually on a monthly basis via the
internet.
It is compatible with all internet enabled devices.
Many important tasks like accounting, sales, invoicing and planning all can be
performed using SaaS.
Example: Salesforce.com
2) PaaS (Platform as a Service)
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It provides a platform and environment to allow developers to build applications and
services and this service is hosted in the cloud and accessed by the users via the
internet and services are constantly updated & new features added. It provides a
platform to support application
development.
It includes software support and management services, storage, networking,
deploying, testing, collaborating, hosting and maintaining applications
Google app engine is an example of Paas
3) IaaS (Infrastructure as a Service)
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It provides access to computing resources in a virtualized environment “the cloud” on
the internet.
It provides computing infrastructure like virtual server space, network connections,
bandwidth, load balancers and IP addresses.
The pool of hardware resources is extracted from multiple servers and networks
usually distributed across numerous data centers. This provides redundancy and
reliability.
Amazon Web Services (AWS) is an example of Iaas
It is a complete package for computing. For small scale businesses who are looking to
cut costs on IT infrastructure, annually a lot of money is spent in maintenance and
buying new components like hard-drives, network connections, external storage
devices etc. which a business owner could have saved for other expenses by using
IaaS.
4) XaaS(Anything as a Service)
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Extensive variety of services and applications emerging for users to access on demand
over the Internet.
There are many other examples of XaaS as follows. Network as a Service, Storage as
a Service, Database as a Service, Information as a Service, Integration as a Service,
Security as a Service, Disaster Recovery as a Service (DRaaS), Communications as a
Service.
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Q.2
(a) Difference between public and private cloud. 03
(b) What are the services provided by SaaS? 04
ANS: Business Services - SaaS Provider provides various business services to start-up the
business.
The SaaS business services include ERP(Enterprise Resource Planning),CRM (Customer
Relationship Management), billing, and sales.
Document Management - SaaS document management is a software application offered by
a third party (SaaS providers) to create, manage, and track electronic documents.
Example: Slack, Samepage, Box, and Zoho Forms.
Social Networks - As we all know, social networking sites are used by the general public, so
social networking service providers use SaaS for their convenience and handle the general
public's information.
Mail Services - To handle the unpredictable number of users and load on e-mail services,
many e-mail providers offering their services using SaaS.
(c) What are the benefits of “Platform As a service”(PaaS)? Explain with
example.07
Ans: PaaS providers provide the Programming languages, Application frameworks,
Databases, and other tools.
1. Programming languages
PaaS providers provide various programming languages for the developers to
develop the applications. Some popular programming languages provided by PaaS
providers are Java, PHP, Ruby, Perl, and Go.
2. Application frameworks
PaaS providers provide application frameworks to easily understand the
application development. Some popular application frameworks provided by PaaS
providers are Node.js, Drupal, Joomla, WordPress, Spring, Play, Rack, and Zend.
3. Databases
PaaS providers provide various databases such as ClearDB, PostgreSQL,
MongoDB, and Redis to communicate with the applications.
4. Other tools
PaaS providers provide various other tools that are required to develop, test, and
deploy the applications.
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Providers
Google App Engine
(GAE)
Salesforce.com
Services
App Identity, URL Fetch, Cloud storage client library,
Logservice
Faster implementation, Rapid scalability, CRM Services,
Sales cloud, Mobile connectivity, Chatter.
Windows Azure
Compute, security, IoT, Data Storage.
AppFog
Justcloud.com, SkyDrive, Google Docs
Openshift
RedHat, Microsoft Azure.
Cloud Foundry from Data, Messaging, and other services.
VMware
OR
(c) Describe Virtual Machine Migration Services. 07
Answer:Virtual machine migration
Process of moving virtual machines from one host server or storage location to another. In the
process all key machine and resources are completely virtualized.
Migration Time: Migration time refers to the total amount of time required to transfer a
virtual machine at source to destination node without affecting its availability.
It is used for load balancing and physical machine fault tolerant. It can also be used to reduce
power consumption in cloud data centres.
Virtual machine migration Techniques:
1) Hot (live) Migration - Virtual machine keeps running while migration and does not lose
its status.
● Also called hot or real time migration
● Movement is done while power is on
● unnoticed with user
● Facilitates proactive maintenance upon failure
● VM should be shared
● CPU compatibility check is required
● Used for load balancing
● Ex: Xen hypervisor
Steps in Hot/Live migration:
Stage 1: Reservation. A request is issued to migrate an OS from host A to host B.
Stage 2: Iterative Pre-Copy. During the first iteration, all pages are transferred from A to B.
Stage 3: Stop-and-Copy Running OS instance at A is suspended, and its network traffic is
redirected to B.
Stage 4: Commitment. Host B indicates to A that it has successfully received a consistent
OS image. Host A may now discard the original VM, and host B becomes the primary host.
Stage 5: Activation. The migrated VM on B is now activated. Post-migration code runs to
reattach the device’s drivers to the new machine and advertise moved IP addresses.
2) Cold (non- live) migration: The status of the VM loses and user can notice the service
interruption
● It occurs when the VM is shut down.
● Also called hot or regular migration
● Movement is done while power is off
● The virtual machines are not required to be on a shared storage
● CPU compatibility check is not required
● Simple to implement
Steps in cold migration
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Step 1: The configuration files, log files, as well as the disks of the virtual machine, are
moved from the source host to the destination host’s associated storage area.
Step 2: The virtual machine is registered with the new host.
Step 3: After the migration is completed, the old version of the virtual machine is deleted
from the source host
Q.3
(a) Write a short note on Load Balancing. 03
• Load balancing is the process of distributing workloads across multiple servers. It prevents
any single server from getting overloaded and possibly breaking down. It improves service
availability and helps prevent downtimes. It uses server to route traffic to multiple server
which in turn share workload
• Without load balancers, newly spun virtual servers wouldn’t’t be able to receive the
incoming traffic in a coordinated fashion or if at all. Some virtual servers might even be
left handling zero traffic while others become overloaded.
• Load balancing divide into three approaches:
❖ Centralized approach: a single node is responsible for managing the distribution within
the whole system.
❖ Distributed approach: each node independently builds its own load vector by collecting
the load information of other nodes. Decisions are made locally using local load vectors.
This approach is more suitable for widely distributed systems such as cloud computing.
❖ Mixed approach: A combination between the two approaches to take advantage of each
approach.
(b) Explain Hyper Visor. 04
❖ A hypervisor is a form of virtualization software used in Cloud hosting to divide and
allocate the resources on various pieces of hardware and provides partitioning, isolation or
abstraction.
❖ This technique allows multiple guest operating systems (OS) to run on a single host
system at the same time, sometimes also called a virtual machine manager (VMM)
❖ A hypervisor allows a single host computer to support multiple virtual machines (VMs) by
sharing resources including memory and processing.
❖ It provides greater IT versatility because the guest VMs are independent of the host
hardware which is one of the major benefits of the Hypervisor. This implies that they can
be quickly switched between servers. it helps us to reduce the Space efficiency, the Energy
uses, Maintenance requirements of the server
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(c) Describe how Virtualization helps to manage Data Center. 07
OR
Q.3
(a) Explain Virtual Clusters. 03
Ans: Virtual clusters are built with VMs installed at distributed servers from one
or more physical clusters.
• The VMs in a virtual cluster are interconnected logically by a virtual network
across several physical networks.
• The virtual cluster nodes can be either physical or virtual machines.
• The size (number of nodes) of a virtual cluster can grow or shrink dynamically.
• VMs can be colonized (replicated) in multiple servers for the purpose of
promoting distributed parallelism, fault tolerance, and disaster recovery.
• There can be multiple clusters & size can vary for each.
(b) Define Porting Applications of virtualization. 04
Answer: Cloud application portability is the degree of extent to which certain
cloud solution providers design applications that can be ported on other providers
and the implementation of standardized, non-proprietary back-end operating
platform for enabling cross-vendor applications.
Cloud application portability mitigates the risk of vendor lock-in and ensures that
the SaaS application is built over open standards and is portable on most cloud
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operating platforms. Whether in a traditional model, or a cloud model, vendors of
software obviously want to lock-in clients.
(c) Elaborate CPU virtualization with example. 07
Answer: CPU Virtualization is one of the cloud-computing technologies that requires a
single CPU to work, which acts as multiple machines working together.
Type Of CPU Virtualization:
1. Software-based CPU Virtualization: application code gets executed on the processor and
the privileged code gets translated first, and that translated code gets executed directly on the
processor. guest programs that are based on privileged coding runs very smooth and fast
2. Hardware-Assisted CPU Virtualization: Here, the guest user uses a different version of
code and mode of execution known as a guest mode. The guest code mainly runs on guest
mode. The best part in hardware-assisted CPU Virtualization is that there is no requirement
for translation while using it for hardware assistance.
3. Virtualization and Processor-Specific Behaviour: Despite having specific software
behaviour of the CPU model, the virtual machine still helps in detecting the processor model
on which the system runs. The processor model is different based on the CPU and the wide
variety of features it offers.
4. Performance Implications of CPU Virtualization: CPU Virtualization adds the amount
of overhead based on the workloads and virtualization used. Any application depends mainly
on the CPU power waiting for the instructions to get executed first. Such applications require
the use of CPU Virtualization that gets the command or executions that are needed to be
executed first.
Q.4
(a) Explain Billing and Metering Services. 03
● Pay as you go: the user has to pay only for the service or the space they have
utilized. There is no hidden or extra charge which is to be paid. The service is
economical and most of the time some space is allotted for free.
● Measured Service: supporting charge-per-use capabilities.
(b) Outline the characteristics of server virtualization and application
virtualization. 04
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(c) Explain how to manage Inter Cloud Resource Management. 07
OR
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Q.4
(a) Explain Digital Signatures. 03
Answer: A digital signature is a cryptographic output used to verify the authenticity of data.
A digital signature algorithm allows for two distinct operations:
• a signing operation, which uses a signing key to produce a signature over raw data
• a verification operation, where the signature can be validated by a party who has no
knowledge of the signing key
The main purposes of a digital signature are:
• verification of the integrity of the signed data
• non-repudiation if the signer claims the signature is not authentic
(b) List down the Emerging Cloud Management Standards. 04
(c) Enlist the services that are provided by Azure Cloud. 07
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Q.5
(a) What are the basic Issues of Securing the Cloud? 03
(b) Explain Autonomic Security Storage Area Networks. 04
Ans: SAN (Storage Area Network):
➢ SAN (Storage Area Network) used for transferring the data between the servers and
the storage devices, fibre channels and switches.
➢ Data is identified by disk block. It allows multiple server access to a pool of storage in
which any server can potentially access any storage unit.
➢ Components of Storage Area Network (SAN): Node ports, Cables, interconnect
device such as: Hubs, switches, directors, Storage arrays and SAN management
Software.
➢ Storage traffic over Fibre Channel avoids the TCP/IP packetization and latency issues,
as well as any local area network congestion, ensuring the highest access speed
available for media and mission critical stored data
❖ SAN Benefits:
• Extremely fast data access with low latency.
• Relieves stress on a local area network.
• It is more scalable.
• Often the only solu’n for demanding applications requiring concurrent shared access.
• Users can easily implement various security measures on SAN.
• Storage devices can be easily added or removed from the network
• The cost of this storage network is low as compared to others.
• SAN (Storage Area Network) has better disk utilization.
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❖ Limitations of SAN:
• Its cost and administration requirements—having to dedicate and maintain both a
separate Ethernet network for metadata file requests & implement a Fibre Channel
network can be a considerable investment.
(c) Describe the Google App Engine Architecture and core concepts. 07
Answer: Google App Engine is the typical example of PaaS. Google App Engine is
for developing and hosting web applications and these processes are highly scalable.
The applications are designed to serve a multitude of users simultaneously, without
incurring a decline in overall performance.
OR
Q.5
(a) List out various Challenges for Cloud Security. 03
Answer: Common Cloud Security Threat
● Identity, authentication and access management – This includes the failure to use
multi-factor authentication, misconfigured access points, weak passwords, lack of
scalable identity management systems, and a lack of ongoing automated rotation of
cryptographic keys, passwords and certificates.
● Vulnerable public APIs – From authentication and access control to encryption
and activity monitoring, application programming interfaces must be designed to
protect against both accidental and malicious attempts to access sensitive data.
● Account takeover – Attackers may try to eavesdrop on user activities and
transactions, manipulate data, return falsified information and redirect users to
illegitimate sites.
● Malicious insiders – A current or former employee or contractor with authorized
access to an organization’s network, systems or data may intentionally misuse the
access in a manner that leads to a data breach or affects the availability of the
organization’s information systems.
● Data sharing – Many cloud services are designed to make data sharing easy across
organizations, increasing the attack surface area for hackers who now have more
targets available to access critical data.
● Denial-of-service attacks – The disruption of cloud infrastructure can affect
multiple organizations simultaneously and allow hackers to harm businesses without
gaining access to their cloud services accounts or internal network.
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(b) Write a short note on Identity Management and Access Control. 04
(c) Explain how to perform Disaster Recovery in Clouds? 07
➢ Cloud disaster recovery (CDR) is a cloud-based managed service that helps you
quickly recover your organization’s critical systems after a disaster and provides you
remote access to your systems in a secure virtual environment.
➢ Cloud disaster recovery has changed everything by eliminating the need for
traditional infrastructure and significantly reducing downtime.
➢ It takes a very different approach than traditional DR. Instead of loading the servers
with the OS and patching to the last configuration used in production, cloud disaster
recovery encapsulates the entire server, which includes the OS, applications, patches,
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and data into a single software bundle or virtual server. The virtual server is then
backed up to an offsite data centre on a virtual host. It is not dependent on HW, the
OS, applications and data can be migrated from one Data Centre to another faster.
Why Disaster Recovery:
• Creating protocols for disaster recovery is vital for the smooth operation of business.
In the event of a disaster, a company with disaster recovery protocols and options can
minimize the disruption to their services and reduce the overall impact on business
performance.
• Minimal service interruption means a reduced loss of revenue which, in turn, means
user dissatisfaction is also minimized.
• Having plans for disaster in place also means your company can define its Recovery
Time Objective (RTO) and its Recovery Point Objective (RPO). The RTO is the
maximum acceptable delay between the interruption and continuation of the service
and the RPO is the maximum amount of time between data recovery points.
• Most successful disaster recovery strategy that never be implemented, therefore, risk
avoidance is a critical element in the disaster recovery process.
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