1 - Intro Flashcards
Public Cloud
Infrastructure for general public or large industry group
Low cost, low trust and low flexibility
Hybrid Cloud
Composition of two or more clouds (private, community or public) that remain unique entities but are bound together by tech that enables data and app portability
Medium cost, medium trust and medium flexibility
“by tech” can mean proprietary or standardised
Community Cloud
Infrastructure shared by several orgs and suports a specific community with specific joint concerns. Can be on or off premise.
Variable cost, High flexibility (limited by policies), High trust
Private Cloud
Operated for one org, internal or external host. Can be on or off premise
High cost, trust and flexibility
IaaS
Infrastructure as a Service
Deploy arbitrary software, can include operating systems
No control of HW
The user is provisioned virtual machines of their choosing
Paas
Platform as a Service
Deploy consumer-created apps using programming lang provided by provider.
User controls deployed apps
The user has no infrastructure control
Saas
Software as a Service
Only apps provided by service are run on the service
Where is cloud infrastructure hosted?
Physically (not where they are logically on the internet)
Datacentres of various sizes
Why should companies move IT to cloud?
Reduce capital expenditure
Always up to date
High availability
Scalable
Reason(s) not to move IT to cloud
Retain full control of data & hardware
Concerns when moving to cloud
Loss of control
Lack of trust - who can access?
Multitenancy
What does multi-tenancy mean?
Sharing infrastructure with others (likely strangers)
Can a company use more than one cloud type at once
Yes.
NHS Trusts: Community Cloud MUST be used?? True or false
False. It may be favourable but perhaps private cloud may be quicker in the short term
For a retail company moving its infra to cloud, which model might it use?
Hybrid - Public for customer services and private for storing business sensitive data
Advantage of IaaS over Paas
IaaS provides greater flexibility
Advantage of Paas over IaaS
PaaS removes the need to set up and maintain deployment environments.
Definition of Cloud Computing
model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable resources.
These can be rapidly provisioned and released with minimal effort or service provider interaction.
Attributes of Cloud Computing
On-Demand self service
Accessible via the internet
Rapid elasticity
Utility computing
Resource pooling
What is On-Demand Self Service
Anytime, Anywhere; often with 99.9% (three
nines) to 99.999% (five nines) uptime guarantee
You can provision the exact amount of resource you need at any time by yourself
What does the attribute “accessible via the internet” mean?
In terms of network access
Requires broad network access; slow service response time impairs usability
What is Rapid elasticity
Rapid resource scaling, e.g., dealing with ‘flash crowd’
What is utility computing
Metered like utilities, e.g. water, gas, electricity.
Only pay for what you use.
What is Resource Pooling
All compute resources are put into a single pool via resource virtualisation
