Cloud concepts

Question 1

Describe the shared responsibility model of cloud computing

Answer 1

Customer always responsible for:
- Information/data stored in the cloud
- Devices that are allowed to connect to the cloud
- Accounts and identities of the people, services and devices within the organisation

Cloud provider always responsible for:
- The physical datacenter
- The physical network
- The physical hosts

Service model determines responsibility for:
- Operating systems
- Network controls
- Applications
- Identity and infrastructure

Question 2

Different cloud models

Answer 2

• Private cloud: cloud that’s used by a single entity
• Public cloud: cloud is built, controlled and maintained by a third-party. Anyone can purchase cloud services and access resources
• Hybrid cloud: environment that uses both private and public clouds
• Multi-cloud: use multiple public cloud providers
• Azure Arc: helps customers manage a cloud environment, either public Azure or private
• Azure VMware: allows for running of VMware workloads in Azure

Question 3

Describe the difference between Availability and Scalability

Answer 3

• High availability focuses on ensuring a service is up and availability for use for the amount of time specified in the SLA (e.g. 99%, 99.9%).
• Scalability refers to the ability to adjust resources to meet demand. The two types of scaling are: Vertical (adding more compute power to existing virtual machines) and Horizontal (adding more virtual machines)

Question 4

Benefits of Cloud: Reliability and Predictability

Answer 4

• Reliability: ability of a system to recover from failures and continue to function. Cloud enables reliability via its decentralised design by having resources deployed in multiple regions around the world (i.e. if one datacenter goes down, another takes over immediately).
• Predictability:
  Performance predictability focuses on predicting the resources needed to deliver a positive experience for you customers, via approaches like autoscaling, load balancing, and high availability.
  Cost predictability is focused on predicting or forecasting the cost of cloud spend.

Question 5

Describe Infrastructure as a Service (IaaS)

Answer 5

• Cloud provider is responsible for maintaining hardware, network connectivity and the physical security.
• Customer is responsible for everything else: operating system, installation, configuration, maintenance, network configuration, database and storage configuration etc.
• It is the most flexible category of cloud services, providing the customer with maximum amount of control of cloud resources.

Question 6

IaaS Scenarios

Answer 6

• Lift-and-shift migration: customer sets up cloud resources similar to their on-prem datacenter, and then simply moves the things running on-prem to running on IaaS
• Testing and development: customer has established configurations for dev and testing environments that need to be rapidly replicated. They can start up or shut down environments rapidly with IaaS

Question 7

Describe Platform as a Service (PaaS)

Answer 7

• Cloud provider maintains the physical infrastructure, physical security, and connection to the internet. They also maintain the operating systems, middleware, development tools, and business intelligence services that make up a cloud solution.
• Customer maintains (as usual) the information/data, devices and accounts/identities, but additionally may maintain Identity and directory infrastructure, applications, and network controls.

Question 8

PaaS Scenarios

Answer 8

• Development framework: PaaS provides a framework that developers can build upon to develop or customise cloud-based applications. PaaS lets developers create applications using built-in software components
• Analytics/BI: tools provided as a service with PaaS allow organisations to analyse and mine their data

Question 9

Describe Software as a Service (SaaS)

Answer 9

• Most complete cloud service model, whereby the customer is essentially renting or using a fully developed application
• Cloud provider maintains everything apart from information/data, devices and accounts/identities
• Least flexible but easiest to get up and running

Question 10

SaaS Scenarios

Answer 10

• Email and messaging
• Business productivity applications
• Finance and expense tracking