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Jason Zhu edited this page 2022-09-14 19:35:35 +10:00
Table of Contents

Chapter 1: What is Cloud Computing?

What is cloud computing?

Cloud computing: term used to describe on-demand access to IT services (e.g. network, storage, software services, etc) via public internet or WAN (wide area network) access.

The six advantages of cloud computing

  • Trade capital expense for variable expense: Instead of hosting on-premises infrastructure, moving to cloud computing provides benefits (i.e. it offers a better way for paying the infrastructure)
    • pay same infrastructure only as and when you consume them
    • shift away from CAPEX (capital expense) to OPEX (operating expense, or variable expense)
  • Benefit from massive economics of scale: Company or person has to purchase hardware/software using retail price, while AWS can purchase in bulk and then distribute to its customers using lower purchasing price.
  • Stop guessing capacity
  • Increase speed and agility: Cloud vendors (e.g. AWS) enable customers to launch and configure new IT resources with few mouse clicks
  • Stop spending money running and maintaining data centers: maintein on-premises infrastructure have hidden costs (requires capital investment and long-term employment of professional teams)
  • Go global in minutes

Exploring the basics of virtualization

Hardware resources are rarely consumed to their maximum capability by a single OS:

  • Hardware improved significantly as shown by Moore's law
  • Software become more efficiently due to advance of software architecture

Virtualization: one core tech used to enable cloud computing.

  • Virtualization + Hypervisors made it possible to emulate the physical hardware components of a single physical server as multiple virtual components (i.e. Virtual Machines)

Hypervisor: a software sits between physical hardware and VMs

  • Responsibility: enable OS & app (contained in VM) to access resources of physical hardware in a controlled manner.

Virtual Machines: each VM contain OS and a suite of app

Figure 1.2 Traditional physical architecture vs virtualized architecture

Benefit of virtualization: reduce provision time of resources dramatically compare to physically provision a physical server

Virtualization vs Cloud computing

One primary service of cloud computing provider: provision virtualized infrastructure resources using a self-service management tool.

Tools offered by AWS:

  • Management Console (via web browser)
  • Command-line interface (CLI)
  • Application programming interface (APIs)

Exploring cloud computing models

Line-Of-Businesss (LOB): apps developed by companies that need to run on web infrastructure

3 main cloud models offered by vendors

  • Infrastructure as a Service (IaaS): customer can/need configure underlying network, storage, and compute services to power their LOB apps.
    • e.g. EC2, EBS, EFS, Azure VM
  • Platform as a Service (PaaS): provider provision infrastructure (OS, compute, storage, network services, runtime environment) needed to deploy app. e.g. from AWS
    • e.g. AWS Elastic Beanstalk, AWS OpsWorks, AWS Lambda, Amazon Relational Database Service (RDS)
    • e.g. Azure Functions
  • Software as a Service (SaaS): app completely hosted/managed by provider
    • e.g. Salesforce, Microsoft Office 365

Understanding cloud deployment models

3 primary models of deployment:

  • Public cloud
  • Private cloud
  • Hybrid cloud