💡 AZ-900 Cheat Sheet – Microsoft Azure Fundamentals

☁️ Cloud Concepts

• IaaS: Virtual Machines, Load Balancers

• PaaS: Azure App Service, Azure SQL Database

• SaaS: Office 365, Dropbox, Outlook.com

• Cloud Benefits:

  • High Availability

  • Scalability (Vertical/Horizontal)

  • Elasticity (Auto-scale with demand)

  • Agility & Speed

  • Disaster Recovery & Fault Tolerance

  • Shift from CapEx (hardware) → OpEx (subscription)

🌐 Network Models

• Peer-to-Peer (P2P):

  • No central server

  • Each device acts as both client and server

  • Good for small or temporary networks (e.g., file sharing apps)

  • Not ideal for business environments

• Client-Server:

  • Central server manages requests from clients

  • Easier to manage, secure, scalable

  • Standard model for most business networks

• Hybrid Network:

  • Combo of P2P and client-server

  • Offers flexibility but can be complex

• In Azure Networking:

  • VNet Peering: Connects two Azure virtual networks

  • Point-to-Site VPN: Secure connection for individual users

  • Site-to-Site VPN: Connect on-premises to Azure

  • ExpressRoute: Private, high-speed connection bypassing the internet

🧰 Core Azure Services

🔐 Security & Identity

• Azure AD: Central identity and access management

• RBAC (Role-Based Access Control): Granular permissions

• NSG (Network Security Group): Inbound/outbound rules

• Azure Firewall: Layer 3–7 filtering

• Azure Key Vault: Stores secrets, keys, and certificates

• Security Center: Monitor and improve security posture

• Azure Policy & Blueprints: Enforce standards across resources

💰 Pricing, SLA & Support

• Pricing Tools:

  • Azure Pricing Calculator

  • TCO Calculator

• Support Plans:

  • Basic: Free

  • Developer: Email only

  • Standard: 24/7 phone support

  • Pro Direct: Fastest + extra features

• SLAs:

  • Single VM: 99.9%

  • VM in availability set: 99.95%

  • VM in availability zones: 99.99%

📈 Monitoring & Management

• Azure Monitor: Metrics and logs

• Log Analytics: Advanced queries (KQL)

• Alerts: Auto-notifications

• Azure Advisor: Personalized recommendations

• Azure Service Health: Track issues in your region

🏗️ Azure Structure

• Regions: Geographic areas (e.g., West Europe)

• Availability Zones: Physically separate datacenters

• Resource Groups: Logical containers for resources

• Subscriptions: Billing/account boundary

• Management Groups: Organize multiple subscriptions

📋 Governance

• Tags: Metadata for resources

• Locks: Prevent accidental changes

• Azure Policy: Enforce rules (e.g., only specific VM sizes)

• Blueprints: Pre-defined templates for compliance

⚡ Quick Tips to Remember

• ARM Templates = Infrastructure as Code

• NSGs filter traffic; Firewalls inspect deeply

• Azure AD handles identity; Key Vault handles secrets

• Public Preview ≠ SLA

• Availability Set = High availability inside 1 datacenter

• Availability Zone = High availability across datacenters

• Azure Arc = Manage multi-cloud/on-prem from Azure

• Azure Stack = Run Azure in your datacenter