02 - cloud computing

cloud computing

cloud computing is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (eg. networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction
NIST

the consumer generally does not own the infrastructure, they pay for the services used
so it is fully on-demand and utility-based
characteristics:
- on-demand self-service
- broad network access
- resource pooling (storage, memory, processing, network bandwidth)
- rapid elasticity: resources assigned accurately and quickly, able to absorb significant increases and decreases in demand without service interruption or quality degradation
- measured service

cloud service models

image: Lucid Content

cloud solutions come in three primary service models
Infrastructure as a Service (IaaS) gives access to storage, networking, servers, and other computing resources via the cloud
user is responsible for managing their applications, data, middleware, etc
provides automated and scalable environments with a high degree of control and flexibility for the user
used by businesses to support workload spikes
eg: Amazon Web Services (AWS), Microsoft Azure, Google Compute Engine (GCE),
Platform as a Service (PaaS) is renting out cloud-based platforms for users to develop and deliver applications
for developers and operations professionals
provides a framework that makes it easier and more efficient to build, customize, and deploy applications
Software as a Service (SaaS) is when software is hosted, packaged, and delivered by a third party through the internet
so enterprises can offload the costs of management and maintenance to the vendors
eg: email, customer relationship management software

public cloud has all the services and supporting infrastructure managed off-site over the internet and shared across multiple users (or tenants)
eg. at the individual consumer level is Netflix, where users subscribe through an individual account, but access the same services across the platform
major advantages are increased efficiency and subsequent cost-effectiveness from shared resources
users do not need to pay for services they are not using or worry about managing and maintaining the physical infrastructure
private cloud provides services through the internet or a private network to select users
typically has a single tenant
all the data is protected behind a firewall
great for businesses requiring agility of the cloud with greater customisation, security and compliance priorities
they can reside on/off-site
the single, private tenant maintains greater control
hybrid cloud combines these two to varying degrees
operate independently but communicate over an encrypted connection, allowing portability of data and apps
increasingly popular due to flexibility