Introduction to Cloud Computing

Introduction
to Cloud
Computing

BCA(SEM: III) DIV-A
Bhuvanesh Hingal
(19030121024)
Vivek Singh
(19030121097)
Made By:-

Internet, it is a massive collection of networks where resources are globally
networked, in internet cloud computing it plays a most important role in order to
share the information and one of the important hi-tech in the cloud computing is
virtualization. Most of it is used to maintain the collection of IT resources which
are used by the cloud providers.
This presentation presents an overview of the cloud computing scenario. It
provides the types of cloud, different examples of the cloud services, different
enterprises in the field of cloud computing, overview of Virtualization,
Hypervisors, their types and example.
INTRODUCTION

What is an OS?
An Operating System (OS) is a software which acts as an interface between the
end user and the computer hardware.
Functions of an OS:

What is a Kernel?
The kernel is the central component of a computer operating systems. The only
job performed by the kernel is to manage the communication between the
software and the hardware. A kernel is like the nucleus of the computer.

Inter-Process Communication(IPC)
Inter Process Communication through shared memory is a concept where two or
more processes can access the common memory and communication is done via
this shared memory where change is made by one process can be viewed by
another process.
Shared Memory: The area of memory which is shared by two processes for
reading and writing. *ACID properties to prevent dirty data.
Semaphore Lock: Locks on a particular block in an OS to protect the read and
write.

In an OS, Data sharing is possible by means of the message queue, shared memory and
semaphore.
A B
C
A = B
Memory is allocated
B = C
Producer Message Queue
Consumer
A = C
Transitive Properties

Semaphore
Semaphore: It is simply a variable that is non-negative and shared between
threads. A semaphore is a signaling mechanism, and a thread that is waiting on a
semaphore can be signalled by another thread. It uses two atomic operation
1) Wait
2) Signal
for the process synchronization.
A semaphore allows or disallows access to the resource, which depends on how
it is set up.

Figure: - Shared Memory Architecture
Figure:- Shared Disc and Shared Nothing Architecture
Parallel Database Architectures

Shared Memory Architecture
In the shared-memory architecture, the entire memory, i.e main memory and disks are
shared by all the processors.
A special , fast interconnection network (eg. a high-speed bus) allows any processor to
access any part of the memory in parallel.
All processors are under the control of a single operating system which makes it easy to
deal with load balancing.
It is also very efficient since the processors can communicate via the main memory.

Shared Disc Architecture
In the shared-disc architecture , only discs are shared by all the processors through the
interconnection network.
The main memory is not shared : each processor has exclusive access to it’s (non-shared)
main memory.
Each processor-memory is under the control of its own copy of the operating system.
shared -disc has a number of advantages like lower cost , availability , load balancing and
easy migration.
But since any processor can cache the same disc page , a cache mechanism is necessary.

Shared Nothing Architecture
In the shared-nothing architecture , each node of processor , main memory and disc
communicates with other nodes through the interconnection network.
Each node is under the control of its own copy of the operating system and thus can be
viewed as a local site (with its own database and software) in a distributed database
system.

What is a Cloud?
Cloud is a cluster of resources , by which users can access application as utilities
via internet, which is stored in some remote location.
Cloud provides services over public networks or on private networks such as on
WAN, LAN or VPN.

Cloud is building cluster of resources over the network for accessibility.
Node A
Node C
Node B Time
Synchronization
☁ The node which initiates the transaction is known as coordinator.
☁ Other nodes which takes part in the transactions are named as subordinates.

What is Cloud Computing?
Cloud Computing is manipulating, configuring, and accessing the applications
online. It offers online data storage, infrastructure and application.
It is a combination of software and hardware based computing resources
delivered as a network service.
Data centres are the centralized locations where computing and networking
equipments are located for the purpose of collecting, storing, processing,
distributing or allowing access to data.

Virtualization
Virtualization is the process of separating the software layer of a computer or server from
the hardware layer of a computer or server. A new layer is placed between the two to act as
a go between.
This could also be explained as the creation of many virtual or artificial resources from one
physical resource (a computer or server) or the creation of one virtual or artificial resource
from one or more physical resources.
The virtualization concept can relate to various areas like networking, storage and
hardware.
The Virtualization enables one computer to carry out the job of multiple computers, with
the help of sharing resources of single hardware across several environs.

Hypervisor
Hypervisors are virtual machine monitors(VMM) that allow numerous virtual operating
systems to simultaneously run on a single computer system. These virtual machines are
also called guest machines and they all share the hardware of the physical machine like
processor, memory, storage and other associated resources. This improves and enhances
the utilization of resources.
The hypervisor isolates the primary host machine from the operating systems. The
hypervisor caters to the needs of a guest operating system and it also manages it
efficiently. Each virtual machine is independent body and does not interfere with each
other despite running on the same host machine. They are not at all connected to each
other. If at a time one of the virtual machines faces any issues or crashes, the other
machines continue to perform it as it is.

Types of Virtualization
There are mainly 2 types of virtualization :-
1. Full virtualization.
2. Para virtualization.
The full virtualization and paravirtualization are categorized under CPU
virtualization. These are mainly distinguished by the fact that in full
virtualization the unmodified OS is not aware about the virtualization and it uses
binary translation to trap the OS calls at the run time. Conversely, in
paravirtualization, the hypercalls are used in place of non-virtualizable OS
instructions and this whole process takes place at the compile time where these
instructions are handled.

Full Virtualization
Full virtualization is the first generation of the software solution regarding server virtualization and
developed in the year of 1966 by IBM. It works by merging the binary translation and the direct execution
where the guest OS is entirely separated from the elementary hardware and virtualization layer.
Therefore, whatever the virtual machines are producing a dynamic translator rewrites to the under-lining
hardware. It involves a lack of awareness at the guest OS end about its virtualization and modification is
inevitable.
The technologies provide full virtualization support are VMWare, ESXi and Microsoft virtual servers.
Each time an OS instruction is generated the hypervisor translates it during run-time quickly and caches
the outcome for the future references. While the user-level instructions are executed without
modification at native speed.

Para Virtualization
Paravirtualization is nothing but the interaction of the guest OS to the hypervisor in order to
boost performance and productivity. Unlike full virtualization, paravirtualization does not
implement complete isolation; instead, partial isolation is implemented in the approach. It
also alters OS kernel to substitute the hypercalls in place of non-virtualizable instructions.
The purpose of hypercalls is to interact with the virtualization layer hypervisor directly.
In paravirtualization, there are various functions performed by hypervisor such as the
arrangement of hypercalls interface for other crucial kernel functions like memory
management, time keeping and interrupt handling. The major merit of paravirtualization is
that it can easily reduce the virtualization overhead.

Conclusion :-
The full virtualization is different from paravirtualization because in full virtualization the
unmodified OS runs in a complete isolated way. On the other hand, in the paravirtualization, the
Virtual machine does not completely isolate the OS but modifies it in order to make it compatible
with the certain API’s.

Virtualization Vs. Cloud Computing
Though they are equally important technologies. Virtualization and cloud computing are not
interchangeable or the same. Virtualization is a software that makes computing
environments self sufficient and independent of physical infrastructure, while cloud
computing is a utility that performs shared computing resources(software and/or data) on
demand with the help of the Internet. As complementary solutions the organizations could
begin with virtualizing their servers and then moving towards cloud computing for even
better agility and self service.
☁ Virtualization is one of the integral parts of cloud computing that helps in the origination of cloud
computing.
☁ Cloud computing is based upon IaaS whereas virtualization works on SaaS.

IaaS vs. PaaS vs. SaaS
IaaS is infrastructure hosted in the cloud. IaaS includes virtual servers and cloud
storage, cloud security, and access to data center resources (managed by the IaaS
provider).
IaaS: cloud-based services, pay-as-you-go for services such as storage, networking, and
virtualization. IaaS examples: AWS EC2, Rackspace, Google Compute Engine (GCE),
Digital Ocean, Magento 1 Enterprise Edition*.

Platform-as-a-Service (PaaS) is the next layer up from IaaS in the cloud computing service
model. It provides developers with a platform for building applications. Most PaaS offerings
include development tools, middleware, operating systems, databases and database
management, and infrastructure. A PaaS provider either manages the infrastructure
themselves or purchases it as a service from an IaaS provider.
PaaS: hardware and software tools available over the internet. PaaS examples: AWS Elastic
Beanstalk, Heroku, Windows Azure (mostly used as PaaS), Force.com, OpenShift, Apache
Stratos, Magento Commerce Cloud.
Software-as-a-Service (SaaS) is full applications hosted and managed in the cloud. SaaS users
subscribe to an application and access it over the Internet rather than purchasing it once and
installing it locally.
SaaS: software that’s available via a third-party over the internet. SaaS examples:
BigCommerce, Google Apps, Salesforce, Dropbox, MailChimp, ZenDesk, DocuSign, Slack,
Hubspot.

Security in cloud
Cloud security, also known as cloud computing security, consists of a set of policies,
controls, procedures and technologies that work together to protect cloud-based systems,
data, and infrastructure.
1. Keeping admins permission.
2. Firewall protection.
3. Distributive / hybrid storage.
4. Data backup.
5. Encryption.
6. Data privacy.
7. Keeping track of the access.
8. With the help of key-stone
tokens.
Security in cloud can be achieved by :-

01
COMPUTE
Memory, CPU
03
NETWORK
Pool of IP
addresses
02
STORAGE
Storage Devices
Terminology Used in Cloud Services

COMPUTE
Compute is a kind of service which takes care about the CPU, availability of resources,
memory and storage. It relates to the infrastructure and decides whether all the resources
are provided to the user/customer or not but never does the resource management, it is
done by other scheduler.
Compute instantiates the resources based upon the customer demands.
Compute interacts with the hypervisor and the resources to the compute are provided by
the hypervisor, thus cloud is going to get all the resources through compute.
☁ Compute ⇒ Cloud
☁ Hypervisor ⇒ OS

STORAGE
A kind of device (dump device) used to store the data. The storage is always going to be
limited in size. The storage component in the cloud services provides the data in a clustered
storage over the network which can be accessible to the customer from any geographical
location.
☁ Provides agility, global scale and durability, with “anytime, anywhere” data access.
Cloud storage is a cloud computing model that stores data on the Internet through a cloud
computing provider who manages and operates data storage as a service. It’s delivered on
demand with just-in-time capacity and costs, and eliminates buying and managing your own
data storage infrastructure.

NETWORK
Cloud needs to have a pool of IP addresses and the pool of IP addresses are going to be
provided by the hypervisor to the network services of the cloud.
Cloud networking is a type of infrastructure where network capabilities and resources are
available on demand through a third-party service provider that hosts them on a cloud
platform. The network resources can include virtual routers, firewalls, and bandwidth and
network management software, with other tools and functions becoming available as
required. Companies can either use cloud networking resources to manage an in-house
network or use the resources completely in the cloud.
☁ Advantages: Versatility, Speed, Reliability, Cost-saving.

OpenStack Core Services
★ Scalability :- It represents how the cloud environment can scale up itself so
that it can handle the multiple customer requirements.
★ Orchestration :- Even if a customer demands 100 different instances per
hour, the services should be able to handle those requirements as per the
user’s choice. Thus, the service which takes care of scaling up/down the
availability as per the requirement is termed as orchestration.
★ Telemetry Service :- As it is based upon pay-as-you-go model, it records the
resource usage statistics of individual customer and generates the bill.
★ Object Storage Service :- This service provides to store unstructured data.
★ Networking Service :- Pool of IP addresses are granted by OpenStack
networking service. It gives the traffic flow from the end user to the cloud
environment

Terminologies in OpenStack Platform
1. Compute ---> Nova
2. Block Storage ---> Cinder
3. Object Storage ---> Swift
4. Orchestration ---> Heat
5. Networking ---> Neutron
6. Image Storage ---> Glance
7. Identity and access management ---> Keystone
☁ Nova , Cinder , Swift , Heat , Neutron , Glance , Keystone these are the services
which provides functionalities respective to their belonging cloud services.

Request Flow for Provisioning Instance in OpenStack

OpenStack - Neutron - Networking Service
These are of mainly 3 types :-
1. Management Network.
2. Data Network.
3. External Network.

1. Management Network :-
It’s responsible to build communications channel between the different cloud services
(i.e : compute , storage , network).
1. Data Network:-
It’s a communication channel with the help of which multiple virtual machines can
interact with each other.
1. External Network:-
It’s a customer network by which the cloud is going to be accessed.
☁ All the different components of the cloud services interact with each other using a
network.

KEYSTONE
03
04
01 Simple/Plain Token
UUID: Universally Unique
Identifier
Compressed PKI
PKIZ
Cryptographically Signed Document
PKI: Public Key Infrastructure
Cryptographically Encrypted Token
Fernet
02
Token Formats:-

Introduction to Cloud Computing

What is a Fernet Key?
A fernet key is used to encrypt and decrypt fernet tokens. The keys are held in a
key repository that keystone passes to a library that handles the encryption and
decryption of tokens.
What are the different types of keys?
A key repository is required by keystone in order to create fernet tokens. These
keys are used to encrypt and decrypt the information that makes up the payload
of the token. Each key in the repository can have one of three states. The state of
the key determines how keystone uses a key with fernet tokens. The different
types are as follows:

★ Primary Key :-
There is only ever one primary key in a key repository. The primary key is allowed to encrypt and
decrypt tokens. This key is always named as the highest index in the repository.
★ Secondary Key:-
A secondary key was at one point a primary key, but has been demoted in place of another primary
key. It is only allowed to decrypt tokens. Since it was the primary at some point in time, its existence
in the key repository is justified. Keystone needs to be able to decrypt tokens that were created with
old primary keys.
★ Staged Key:-
The staged key is a special key that shares some similarities with secondary keys. There can only ever
be one staged key in a repository and it must exist. Just like secondary keys, staged keys have the
ability to decrypt tokens. Unlike secondary keys, staged keys have never been a primary key. In fact,
they are opposites since the staged key will always be the next primary key. This helps clarify the
name because they are the next key staged to be the primary key. This key is always named as 0 in
the key repository.

Cache of the token is kept here
and the token validation is
done here
Keystone
Middleware
☁ In UUID, keystone validates the token.
☁ In PKI, keystone middleware validates the token.

“Cloud is about how you do computing, not
where you do computing.”

Introduction to Cloud Computing

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