Cloud computing

Question 1

Users expect a cloud infrastructure to support:

Answer 1

The illusion of infinite computing resources available on-demand
The elimination of up-front commitment by users
The ability to pay for use of computing resources on a short-term, as-needed basis

Question 2

Cloud Components: Clients

Answer 2

Clients are the devices used to interact and manage information on the cloud.
They generally fall into 3 categories
Mobile. Devices such as IPads, iPhone, SmartPhone.
Thin. Clients are computers with no storage, allow the server to do all the work and simply display information.
Thick. Clients are regular computers using browsers to
connect to the Cloud.

Question 3

Thin clients: Advantages

Answer 3

Lower Hardware Costs
Lower IT Costs
Security
Data Security (in the event of hardware failure)
Less Power consumption
Ease of Repair or Replacement
Less Noise (no fans)

Question 4

Cloud Components: Datacenter

Answer 4

The datacenter is the collection of servers where the target application is housed.
Its location is varied: a basement, a server farm, a remote location or country.
A growing trend is virtualising servers.
Multiple instances of the same server can be used on a single physical server.
The number of virtual servers depends on the size and speed of the physical server and the types of applications

Question 5

Cloud Components: Distributed Servers

Answer 5

Servers can be in different geographic locations but this is hidden from the end-user.
This gives the service provider more flexibility in options and security.
Amazon maintain their cloud solution in servers around the world. If one site fails, access is provided through a second site.
If more computing power (hardware) is required, it is not necessary to add more to their server room. Instead, they can be added to any location and made part of the cloud.

Question 6

Infrastructure

Answer 6

There is no single configuration: a Cloud Computing infrastructure can be deployed in several ways.

This is one of the benefits of the cloud.
If your requirements are large scale and possibly too big for your organisation, use the Cloud Computing services.
If your requirements are tiny and not worth buying the infrastructure, use the Cloud Computing services.

Question 7

Grid Infrastructure

Answer 7

Grid Computing is often confused with Cloud Computing: they are quite different!
Grid Computing applies the resources of numerous computers in a network to work on a “single problem simultaneously”.

Question 8

Grid vs Cloud

Answer 8

Grid Computing uses software that divides a problem among thousands of computers, either throughout an organisation’s computers or in the form of a public collaboration.

Cloud Computing is the opposite: it facilitates multiple smaller applications to run at the same time.

Question 9

Full Virtualisation

Answer 9

Full Virtualisation is a technique where a complete installation of one machine runs on another.

The result is a system where all software running on the server is within the virtual machine.

Question 10

Full Virtualisation Benefits

Answer 10

Virtualisation is important to Cloud Computing as it provides one method of accessing services on the cloud.
The remote datacenter delivers services in a fully virtualised format.
Full Virtualisation has been successful for a number of reasons:
Sharing a computer system among multiple users
Isolating users from each other and from the control program
Emulating hardware on another machine

Question 11

Paravirtualisation

Answer 11

Paravirtualisation allows multiple O/S to run on a single hardware device simultaneously by being more efficient at using resources such as processors and memory.
In Full Virtualisation, the entire system is emulated but in Para, its management center works with a customised O/S (modified for a virtual machine).
The different systems are aware of each other and cooperate for increased efficiency.
Para runs better than Full because in Full, all elements must be emulated.
. . . in other words full emulation (virtualisation).
Guest programs must be specifically modified to run in this environment.

Question 12

Paravirtualisation: The tradeoff

Answer 12

The trade-off is reduced security and flexibility :

Flexibility is reduced as new versions of guest O/S may not work.
The underlying O/S was adjusted to work with the original version of the guest O/S.
Security is compromised as the guest O/S has more control of underlying hardware.
In Full virtualisation, there is effectively a wall between guests and the underlying O/S, and also each other.

Question 13

Paravirtualisation Benefits

Answer 13

Paravirtualisation works best in specific deployments.

Disaster Recovery. In the event of failure, guest instances can be moved to other hardware until the failure is resolved.

Migration. Moving to a new system is easier and faster as guest instances can be removed from the underlying hardware.

Capacity Management. Because of easier migrations,
capacity management is easier to implement. It is easy to add more processing or hard drive capacity in the paravirtualisation environment.

Full Virtualisation also provides all of the above!

Question 14

Myth no.1
My Data Center Is Virtualized So I Already Have the Cloud

Answer 14

Virtualisation is a key component of the cloud, but Cloud Computing requires far more than virtualisation.
What defines the Cloud is the ability to deploy and scale infrastructure:
rapidly and programmatically
on-demand
on a pay-as-you-go basis.
Proper Load Balancing and Sharing!
This is difficult if not impossible to achieve using traditional virtualisation alone.

Question 15

Myth no.2
Cloud Application Performance Is Hampered by Network Latency and I/O Bottlenecks

Answer 15

This is a deployment issue!

Both can be issues, but the degree to which they affect performance depends on:
cloud providers,
network providers,
applications,
cloud deployment architecture.

A carefully architected deployment can often avoid these issues.

Question 16

Myth no.3
I will not have full Ownership of my cloud-based data

Answer 16

You can have full data ownership:
Choose your cloud provider carefully and pay attention to contract terms.

Data ownership can be an issue with consumer social networking sites, but much less likely with an infrastructure provider.

Actions: Negotiate contracts that give you full ownership of your data, with possibly the right to choose the data storage location

Question 17

Myth no.4
My Data will not be Secure in the Cloud

Answer 17

Reputable cloud providers know that any serious security breaches will receive widespread publicity and damage their businesses.

For this reason, public cloud provider security is often better than many large enterprise data centers.

Action:
Customers should examine contracts to ensure that they meet the organisation’s data location, control, and security requirements.
Sensitive data should be encrypted both in transit and in storage.

Question 18

Myth no.5
I’ll Get Locked into a particular Cloud or Provider

Answer 18

This is potentially correct depending on the service you choose.

Start by asking the question: What if I need to move?

Ensure your contract includes detailed (smooth) exit strategy.

Deploy portable cloud configurations that can be migrated quickly from one provider to another.

Utilise deployment tools that enable quick migration and configuration.

Question 19

Myth no.6
The Cloud means there’s no role left for IT

Answer 19

Most organisations will need help from IT to choose, configure, integrate, and monitor cloud services properly and migrate applications and data to the cloud.

The Cloud’s role is to help make IT more agile and responsive in delivering the applications and its (internal) customers require.

With fewer IT resources required for day-to-day operations, IT has more time to spend on the strategic aspect of its role: delivering business value to the organisation.

Question 20

Myth no.7
Cloud Computing Is for SMEs, Not Enterprises

Answer 20

Untrue! Recent studies of RightScale (Cloud platform management company) customers show the biggest growth in Cloud usage comes from enterprises.

Many Cloud providers have geared up for the scalability, security, and customisation needs of enterprise customers, and it has started to pay off.

Larger companies are using the cloud for a variety of applications:
highly scalable websites to social applications,
grid computing for scientific research delivering,
media processing,
employee collaboration, etc

Question 21

Myth no.8
The Cloud Is Always Less Expensive

Answer 21

That depends on several factors:
network and bandwidth requirements,
special hardware needs,
the cloud service and applications under consideration,
the alternative to the Cloud.

When comparing the cost of a cloud deployment, consider:
costs of power, cooling, administration, staffing,
and data center real estate for deploying the same application in-house or in traditional hosting.

Also consider the ”intangible” benefits of increased agility and responsiveness that a cloud deployment often provides.

Business advantages result from quick opportunism

Question 22

Myth no.9
The Cloud Is Always Less Expensive

Answer 22

That depends on several factors:
network and bandwidth requirements,
special hardware needs,
the cloud service and applications under consideration,
the alternative to the Cloud.

When comparing the cost of a cloud deployment, consider:
costs of power, cooling, administration, staffing,
and data center real estate for deploying the same application in-house or in traditional hosting.

Also consider the ”intangible” benefits of increased agility and responsiveness that a cloud deployment often provides.

Business advantages result from quick opportunism

Question 23

Myth no.10
Low Cost Is the Cloud’s Chief Attraction

Answer 23

Low cost is a definite advantage of the cloud, but …..

For many organisations, agility, scalability, time-to-market, and fast access to high-quality infrastructure present more compelling benefits.

Cloud computing allows many businesses to get up and running with new tech quickly or scale computing power to handle peak loads much more rapidly, efficiently, and
cost-effectively than they could possibly do in-house

For many businesses, the cloud provides access to infrastructure at a quantitative scale and level of operational excellence that is otherwise not attainable

Question 24

Services

Answer 24

The term services in Cloud Computing means being able to deploy reusable, fine-grained components across the network.

This is widely known as ”as a service” and has a number of advantages:
Low barriers to entry, making them available to small businesses;
Large scalability;
Multi-tenancy allowing resources to be shared by many users;
Device independence, allowing users to access systems on
different hardware platforms.

Question 25

Software as a Service

Answer 25

Definition: Software as a Service (SaaS) is the model in which an application is hosted as a service to customers who access it via the Internet.

Your motivation is that you use the service as it exists and do not require changes or integration with other systems.
The provider does all the updates and is responsible for infrastructure costs and maintenance.
Gmail is a simple example of a web-based email service

However, the same architecture can be applied to a broad variety of applications:
Line of Business Services. Supply chain management
and customer relationship management.
Customer-Oriented Services. On a subscriptions basis or free, but advertising-based

Question 26

SaaS Benefits

Answer 26

Cost, No need to buy application, less staff.
WWW Familiarity.
Customisation. Older applications were difficult to modify.
Better Marketing. The global nature of the Internet opens a much larger market.
Web Reliability. Generally very high.
Security. SSL is widely used and trusted.
Additional Bandwidth. Improving all the time.

Question 27

Platform as a Service

Answer 27

Platform as a Service (PaaS) supplies all of the resources required to build applications and services completely. There is no need to download or install software.

PaaS services include application design, development, testing, deployment and hosting.
Secondary services might include: team collaboration, web service integration, database integration, security, scalability, storage.

The scenario for PaaS is many concurrent users and features such as concurrency management, scalability and security are built-in.

At present, interoperability is a problem. One cloud provider’s application kit may not work with another.

Question 28

PaaS Options

Answer 28

Add-on Development Facilities. These allow existing SaaS applications to be customised. PaaS developers and subscribers subscribe to SaaS add-ons.

Standalone Environments. They do not include licensing, technical or financial dependencies on specific SaaS applications and are used for generalized development environments.

Application Delivery-Only Environments. Do not include debugging, testing etc. Instead, they support hosting type services such as security and on-demand scalability.

Open platform as a service. Very basic: merely provides open source software to allow a PaaS provider to run applications.

Question 29

Hardware as a Service

Answer 29

HaaS offers the hardware so that an organisation can place required systems on it. Essentially they rent the hardware.

Infrastructure can be scaled up or scaled down.

Multiple tenants can use the equipment at the same time.

Question 30

Database as a Service

Answer 30

The purpose of Database as a Service is to avoid the complexity and cost of running the database.

Ease of Use. Nothing to buy, install or maintain.

Integration. The database can be integrated with other services to provide added value and power (eg. calendars, email etc.).

Management. This function can be housed in a cheaper or more technical labour market.

Question 31

Storage as a Service

Answer 31

The term Storage as a Service (SaaS again!) means a provider rents storage space to end users.

It is ideal where users lack the technical expertise to setup storage infrastructure.

Online storage is not new but SaaS provides replication, backup, disaster recovery to small and medium sized businesses.

Customers use supplied software to decide what is backed up and retrieves lost data from the service provider.

The primary advantage is cost. Customers pay for what they use: per-gigabyte, per space used etc.

Question 32

Local Clouds Overview

Answer 32

A local cloud or presentation virtualisation bypasses the service provider so that one can manage content locally.

Most organisations will not jump to the cloud all at once.

Move small applications but retain the majority in-house (see Migration).

Solution:
- Build a Cloud for your own business.
- Keep the server in-house and allow your customers to connect to it (Normal internet computing).
- Begin to offer services to users as a utility.
- Goal is to provide flexible, low-cost business applications rather than being an organisation with ”just another server”.
- Delivery of services changes by using presentation
virtualisation.

Question 33

Virtualisation

Answer 33

Server Virtualisation. Partition a physical server so that each partition appears as running on a dedicated machine.

Application Virtualisation. Separates the application from the underlying O/S. A fully virtualised app is not installed (in the traditional sense) but executes as if it were (e.g. Citrix).

Presentation Virtualisation. Isolate processing from graphics and I/O, allowing the app to be run on one machine while controlled on another (thin client).

Question 34

Virtualisation Benefits

Answer 34

Reduced Infrastructure Costs. Helps to maximise the value of IT investments; decreasing server hardware footprint; energy consumption; increasing flexibility; reduce cost and complexity of managing IT systems.

Cost. It is possible to have a cost-free datacenter.

Fast Deployment. As every virtual server is a file on a disk, just copy it (for a cloned system).

Question 35

Disadvantages of Virtualisation

Answer 35

Graphics intensive applications are not suited to virtual environments (processing intensive).

Database and business intelligence apps (for the same reason). A small database app will be ok but will not scale.

Apps that require access to dedicated hardware devices are difficult or impossible.

Question 36

Migration Issues :
Which applications do you need? What are you moving? Do you require SaaS, PaaS or Haas?

Answer 36

Sending existing data to the cloud. Must guarantee appropriate levels of security. Many options available, eg. Symantec Online Backup.
The Wave Approach. Similar to rolling out a new O/S:
Start with a small amount of low-importance data.
As more data is added (no problems so far), add data of more importance.
At this point, performance levels should drop. Low
importance data is not accessed to the same extent.
If problems occur, take corrective action or ”walk away”.

Question 37

FaaS (Function as a Service)
What is Function as a Service?

Answer 37

Server-less Computing
Write and update code on the fly.

How can it help with Monolith deconstruction? :

Big banks have developed Enormous code bases that are all intertwined.
Breaking this up can reduce operational costs.