Azure Fundamentals 1 : Cloud concepts and Azure Architecture, Services

Cloud Computing : It is the delivery of computing services over the internet, which is otherwise known as the cloud by using pay-as-you-go pricing model. These services include servers, storage, databases, networking, software, analytics, and intelligence. Cloud computing offers faster innovation, flexible resources, and economies of scale. 

Cloud Computing benefits, use GASHED:

• Geo-distribution
• Agility - ability to react quickly , i.e ability to allocate or deallocate (scale) resources quickly.
• Scalability 
• Scale vertically to increase compute capacity by adding RAM or CPUs to a virtual machine(scaling up or scaling down)
• Scaling horizontally increases compute capacity by adding instances of resources, such as adding VMs to the configuration (scaling in (decrease ) / scaling out (increase))
• Thus, scaling is the process of allocating(adding) or deallocating (removing) resources.
• High Availability  - Uptime/(Uptime + Downtime) , ability to keep services running for extended periods of time with very less downtime
• Elasticity - Automatic scaling, i.e to adjust its processing power to match the demand or the ability to scale dynamically
• Disaster Recovery - Ability to recover from an event that has taken down the service (disaster)
• Fault Tolerance - Ability of the system to remain up and running during component and service failures.

In other words, 

• Lower your operating costs.
• Run your infrastructure more efficiently.
• Scale as your business needs change.

Why cloud?

The cloud provides on-demand access to:

• A nearly limitless pool of raw compute, storage, and networking components.
• Speech recognition and other cognitive services that help make your application stand out from the crowd.
• Analytics services that deliver telemetry data from your software and devices.

Azure Portal : Web-based unified console that allows you to build, manage, and monitor everything in Azure.

Azure Marketplace : Connects users to partners and vendors that offer solutions/services for Azure

Accounts : Azure Account -> Many subscriptions -> Many Resource groups -> Resources

Azure Services Big Picture :

Azure Services :

Types of Cloud :

Expenses :

Consumption Based model :

• No up-front costs
• Pay for what you use or require
• Pay for additional resources only when they are in use
• Stop paying for resources not used

Cloud Service models :

IaaS - Infrastructure-as-a-Service
PaaS - Platform-as-a-Service
SaaS - Software-as-a-Service

Serverless computing

Like PaaS, serverless computing enables developers to build applications faster by eliminating the need for them to manage infrastructure. With serverless applications, the cloud service provider automatically provisions, scales, and manages the infrastructure required to run the code. Serverless architectures are highly scalable and event-driven, only using resources when a specific function or trigger occurs.

Subscriptions, Management Groups, and Resources :

Azure Region : A geographical area with one or more datacenters nearby and networked together.

Special Regions: US DoD, US Gov: physically+logically isolated with additional compliance certifications. China is operated by 21Vianet.

Azure Availability Zones : One or more physically separate datacenters within an Azure region. A.K.A. Isolation Boundary (HA/redundancy).

Availability Zones are interconnected with ultra high-speed, private, fiber network.

Not all regions have AZs.

Services that support AZs have these categories:

• Zonal service: Pins to a zone
• Zone-redundant: Auto-replication across zones
• Non-regional: HA in an Azure geography.

Azure Region Pairs

Each Azure region is always paired with another region within the same geography.

AZs have one or more datacenters, and a Region has at least 3 zones.

Helps protect against natural disasters or civil unrest. Separated at least 300 miles.

Replication resides always within the same Geography as the pair except for Brazil South.

Azure resources and Azure resource Manager

Resource: A manageable item within Azure. Like a database or a VM Resource group: A grouping of resources you want to manage as a group.

Azure Resource Groups

Can contain anything you create in Azure to form a logical grouping of services (resources). Helps provide organization.

• Life cycle: If you delete a resource group, all contained resources are deleted as well. Makes it easier to get rid of.
• Authorization: A resource group is a scope for applying RBAC

Azure Resource Manager

Deployment and management service for Azure. CRUD for Azure resources

• Manage infrastructure with templates
• Deploy, manage, and monitor
• Define dependencies between resources for correct ordering
• Apply RBAC and tags

The following image shows the role Resource Manager plays in handling Azure requests.

Azure subscriptions

Provides authenticated and authorized access to products and services. Always linked back to an account.

An account can have one or many subscriptions.

Types of subscription boundaries:

• Billing boundary: Determines how an Azure account is billed. You can create multiple subscriptions for different billing requirements.
• Access Control boundary: Access-management policies happen at the subscription level. You can control access+resources for specific subscriptions.

Additional subscription helps with:

• Environments: Separate environments via subscriptions. E.g. development and testing
• Org structure: Marketing and IT, helping manage access and limit resources
• Billing: Make it easier to track billing better.

The following diagram shows an overview of how billing is structured

Azure management groups

Provides a level of scope above subscriptions. Helps organize subscriptions into groups.

Helps provide user access to multiple subscriptions with a single RBAC that gets inherited.

Source : https://learn.microsoft.com/en-us/certifications/exams/az-900