Cloud Computing Fundamentals

What is cloud computing?

5 characteristics per NIST 800-145

On-demand self-service
1. 📝 Can provision/terminate capabilities using UI/CLI as needed without requiring human interaction
Broad network access
1. 📝 Capabilities are available over the network, on any device, using standard protocols/mechanisms
Resource pooling
1. Sense of location independence - no control or knowledge over exact location of the resources
2. Resources are pooled to serve multiple consumers using a multi-tenant model
3. 📝 Economies of scale, cheaper service
Rapid elasticity
1. Capabilities (resources) can be elastically provisioned and released to scale rapidly outward and inward with demand
2. To the consumer, capabilities available for provisioning appear to be unlimited
3. In Cantrill's opinion, the most important characteristic of cloud computing
4. 📝 Scale up/out and down/in automatically in response to system load
Measured service
1. Resource usage can be monitored, controlled, reported, and billed
2. 📝 Usage is measured - pay for what you use

📝 Using multiple public cloud providers within a single system
Can provide cloud provider resilience in case one fails
Multi-Cloud environments are most effective when used for high availablity purposes
- 💡 Cantrill says stay away from products/vendors that offer a single management window for multiple cloud platforms because it abstracts the unique features of each provider

Private cloud needs to meet 5 characteristics of cloud computing
- 📝 main difference between public cloud is that it is dedicated to the customer and is located on-premises
Examples: AWS Outposts, Azure Stack, Google Anthos
Private cloud != on-premises infrastructure like VMWare

📝 Using public cloud and private cloud together as a single environment
Use same tooling, interfaces, processes to interact with public and private components
💡 Hybrid environment/networking is different!
- Definition: using public cloud with on-premises infrastructure

Infrastructure stack: collection of things needed by an application
- example stack from bottom to top: facilities, infrastructure, servers, virtualization, O/S, container, runtime, data, application
- parts consumer manages and parts the vendor manages
Unit of consumption: what you pay for and at what point you manage everything upwards

On-premises: you own the entire infrastructure stack
DC hosted: vendor supplies facilities. Unit of consumption is a server rack.

Vendor supplies: facilities, infrastructure, servers, virtualization, O/S, container
Unit of consumption: runtime

if a person is a developer and doesn't want to worry about everything below the runtime