💡 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
| Category | Examples |
|---|---|
| Compute | VMs, App Services, AKS |
| Storage | Blob, File, Disk |
| Networking | VNet, Load Balancer, NSG |
| Databases | SQL DB, Cosmos DB, PostgreSQL |
| Identity | Azure Active Directory (AAD) |
🔐 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