Microsoft Azure Certifications (e.g. AZ-104, AZ-900) Cloud Concepts and Azure Fundamentals (AZ-900 Foundation) Syllabus

Approximately how much downtime per year does an SLA of 99.9% ('three nines') allow?

About 8.76 hours per year. Calculation: $0.001 \times 365 \times 24 \approx 8.76$ hours.

Approximately how much downtime per year does an SLA of 99.99% ('four nines') allow?

About 52.6 minutes per year. Calculation: $0.0001 \times 365 \times 24 \times 60 \approx 52.6$ minutes.

How is composite SLA calculated for two dependent services?

Multiply the individual SLAs together. For two dependent services each at 99.9%: $0.999 \times 0.999 \approx 0.998$, i.e. about $99.8\%$, giving a lower combined SLA than either service alone.

What is elasticity in cloud computing?

The ability to automatically and dynamically allocate or deallocate resources in response to real-time demand, ensuring sufficient capacity during spikes and cost savings during low demand (e.g., autoscaling).

What is reliability in the cloud?

The ability of a system to recover from failures and continue to function. It is a core pillar of cloud architecture, supported by the decentralized, globally distributed design of the cloud.

What is predictability in the cloud, and what two areas does it cover?

Predictability is being confident about performance and cost outcomes. It covers performance predictability (forecasting resources needed via autoscaling, load balancing, high availability) and cost predictability (forecasting and tracking spend using tools like Cost Management and Pricing Calculator).

Which tools support cost predictability in Azure?

The Azure Pricing Calculator, the Total Cost of Ownership (TCO) Calculator, Microsoft Cost Management, and Azure Advisor (for cost recommendations).

What is the security benefit of cloud computing regarding patching and updates?

Cloud providers offer advanced security features, automatic patching and updates of infrastructure, and built-in tools, reducing the security management burden on the customer compared to on-premises environments.

What is governance in the cloud?

The set of policies, rules, and processes that ensure cloud resources comply with corporate standards and regulatory requirements. Azure tools like Azure Policy and Blueprints help enforce governance at scale.

How does the cloud help with governance and compliance?

Cloud platforms provide built-in governance tools (Azure Policy, Management Groups, Blueprints) and broad compliance certifications, allowing organizations to set standards, audit resources, and ensure regulatory compliance consistently and automatically.

What is manageability in the cloud (the two aspects)?

Management OF the cloud — managing cloud resources (autoscaling, automatic deployment from templates, monitoring health, alerting). Management IN the cloud — how you administer, via web portal, CLI, APIs/SDKs, or PowerShell.

Name the main ways to manage Azure resources.

The Azure portal (web GUI), Azure CLI, Azure PowerShell, Azure Cloud Shell, and REST APIs / SDKs. ARM templates and Bicep enable infrastructure as code.

What is an Azure region?

A geographical area on the planet containing at least one, but potentially multiple, datacentres that are nearby and networked together with a low-latency network. Azure has more global regions than any other cloud provider.

What is an Azure region pair?

A relationship between two Azure regions within the same geography, separated by at least 300 miles (~480 km) where possible, used for disaster recovery. If one region has an outage, the paired region serves as backup.

Give an example of an Azure region pair.

Examples include West US paired with East US, North Europe (Ireland) paired with West Europe (Netherlands), and UK West paired with UK South.

Why is the ~300 mile separation important for region pairs?

It reduces the likelihood that a single natural disaster, power outage, or large-scale event affects both regions simultaneously, ensuring at least one region in the pair remains available for disaster recovery.

During a broad Azure outage, how does the platform prioritize region pairs?

Azure prioritizes recovery of one region out of every pair to minimize downtime, and platform updates (planned maintenance) are rolled out to paired regions sequentially (one at a time), not simultaneously.

What is an Azure datacentre?

A physical facility containing the servers, storage, networking, power, and cooling that host Azure services. Datacentres are grouped into Availability Zones and regions.

What are Azure Availability Zones?

Physically separate datacentres within an Azure region, each with independent power, cooling, and networking. A region with Availability Zones has a minimum of three separate zones to protect against datacentre-level failures.

What is the minimum number of Availability Zones in a region that supports them?

Three. Each zone is made up of one or more datacentres with independent power, cooling, and networking.

What is the difference between zonal and zone-redundant services?

Zonal services pin a resource to a specific Availability Zone (e.g., a VM in zone 1). Zone-redundant services automatically replicate or distribute across multiple zones (e.g., zone-redundant storage), surviving the failure of a single zone.

What does an Availability Zone protect against versus what a region pair protects against?

An Availability Zone protects against datacentre-level failures within a region. A region pair protects against region-wide (geographic) disasters by providing a backup in a separate, distant region.

What is a sovereign / specialized Azure region (Azure Government, Azure China)?

Physically and logically isolated instances of Azure built to meet specific compliance, legal, or sovereignty requirements (e.g., Azure Government for US government, Azure China operated by 21Vianet), separate from the global Azure cloud.

List the four levels of the Azure resource management hierarchy from top to bottom.

Management groups -> Subscriptions -> Resource groups -> Resources.

What is an Azure resource?

A manageable item available through Azure, such as a virtual machine, storage account, web app, database, or virtual network. Resources are the most granular level of the hierarchy.

What is an Azure resource group?

A logical container that holds related resources for an Azure solution. Resources can only exist in one resource group at a time, and deleting a resource group deletes all resources within it. Used for grouping by lifecycle, project, or environment.

What is an Azure subscription?

A logical unit of Azure services linked to an Azure account, acting as a billing and access-management boundary. It groups resource groups and provides separation of costs, billing, and quotas/limits.

What is an Azure management group?

A container above subscriptions used to manage access, policy, and compliance across multiple subscriptions at scale. Conditions (policies/RBAC) applied to a management group are inherited by all subscriptions and resources beneath it.

What is Azure Resource Manager (ARM)?

The deployment and management service for Azure. It provides a consistent management layer through which all requests (from portal, CLI, PowerShell, SDKs, REST API) pass, enabling you to create, update, delete, and organize resources with features like access control, tags, and locks.

What is an ARM template?

A JSON file that defines the infrastructure and configuration for an Azure deployment using declarative, infrastructure-as-code syntax. It enables repeatable, consistent, idempotent deployments; Bicep is a simpler domain-specific language that compiles to ARM JSON.