Cloud Concepts

Question 1

High Availability (HA)

Answer 1

The ability of the application to continue running in a healthy state without significant downtime. By ‘healthy state’ we mean the application is:

• responsive
• users can connect to and interact with it

Question 2

Scalability

Answer 2

Increase or decrease the resources used based on demand or workload at any given time.

Question 3

Vertical scaling

Answer 3

Scaling up
Adding resources to increase power of an existing server
e.g. adding faster CPU, additional CPUs, more memory

Question 4

Horizontal scaling

Answer 4

Adding more servers that function together as a unit

Question 5

Elasticity

Answer 5

Automatically add more resources based on demand

Question 6

Cloud Agility

Answer 6

Ability to rapidly change IT infrastructure to adapt to evolving needs of the business.
e.g if usage peaks for a month, you can scale to meet demand and pay more. Vice versa if usage drops

Question 7

Fault tolerance

Answer 7

If one component fails, a backup component takes its place. Fault tolerance ensures customer aren’t impacted when incidents happen

Question 8

Disaster recovery

Answer 8

Ability to recover from rare but major incidents e.g. service disruptions that affect an entire region.
May include;
- data backup and archiving
- manual intervention such as restoring a database from backup

Question 9

Economies of scale

Answer 9

Ability to do things at a lower cost per unit at a larger scale

Question 10

Capital expenditure (CapEx)

Answer 10

Upfront cost that has a value that decreases over time

Question 11

Operational expenditure (OpEx)

Answer 11

No upfront cost, pay for a product as you use it

Question 12

IaaS

Answer 12

Infrastructure as a service (IaaS) is an instant computing infrastructure, provisioned and managed over the internet.

Renting hardware instead of buying - infrastructure, servers, virtual machines, storage, networks

Most flexible category of cloud services

Question 13

PaaS

Answer 13

PaaS provides an environment for building, testing and deploying software application.

Deploy an application without having to manager the underlying infrastructure.

Complete development and deployment environment in the cloud

Question 14

SaaS

Answer 14

Software centrally hosted and managed for the end customer.
Licensed through monthly/yearly subscription
E.g O365, Dynamics CRM

Question 15

IaaS responsibilities - user vs. provider

Answer 15

User
- purchase, install, configure, manage their own software OS, middleware and apps

Provider
- ensure the underlying infrastructure (virtual machines, storage and networking) is available for the user

Question 16

PaaS responsibilities - user vs. provider

Answer 16

User
- development of their own apps

Provider
- OS management, network and service configuration

Question 17

SaaS responsibilities - user vs. provider

Answer 17

User
- Just use the application

Provider
- provision, management and maintenance of the application

Question 18

Public cloud (most common)

Answer 18

Most common deployment model.

Everything runs on cloud providers’ hardware

Question 19

Private cloud

Answer 19

Create cloud environment in own datacenter and provide self-service compute resources to users in your org

Question 20

Hybrid cloud

Answer 20

Combines public and private, allowing you to run apps in the most appropriate location

Question 21

Pros/cons of public cloud

Answer 21

+ high scalability/agility
+ pay as you go (no capex)
+ no hardware maintenance

• may not meet security requirements
• may not meet compliance requirements
• don’t own hardware, may not be able to manage as you want

Question 22

Pros/cons of private cloud

Answer 22

+ complete control
+ can meet strict compliance/security requirements

• upfront capex
• owning equipment limits agility to scale
• requires technical knowledge

Question 23

Pros/cons of hybrid

Answer 23

+ benefits of both public and private

• can be more expensive
• can be complicated to set up/manage

Question 24

Benefits of cloud computing - 7 things to remember

Answer 24

cost effective - pay as you go

scalable - increase/decrease resources based on demand

elastic - automatically add/remove resources based on demand

current - hardware and software is maintained by provider

reliable - backup, disaster recovery, data replication services and redundancy is built in which means if one component fails, a backup takes its place

global - fully redundant datacenters all over the world

secure - broad set of policies, controls and expert technical skills that provide better security than most organisations can achieve.