Microsoft Azure Architecture

Comprehensive guide for building secure, scalable infrastructure on Microsoft Azure.

When to Use

•Designing Azure architecture for new projects
•Deploying applications to Azure services
•Setting up networking (VNet, NSGs)
•Configuring Azure AD/Entra ID and RBAC
•Working with AKS (Azure Kubernetes Service)
•Integrating with Microsoft 365 ecosystem

Core Services Overview

Compute

Service	Use Case	Key Features
Virtual Machines	Full control	Any OS, any workload
AKS	Managed Kubernetes	Azure-integrated K8s
App Service	PaaS web apps	Managed platform
Functions	Serverless	Event-driven, consumption
Container Apps	Serverless containers	Dapr, KEDA built-in
Container Instances	Simple containers	Quick deployment

Storage

Service	Use Case	Key Features
Blob Storage	Object storage	Hot/Cool/Archive tiers
Azure Files	SMB/NFS shares	Cloud file storage
Managed Disks	Block storage (VMs)	SSD/HDD options
Queue Storage	Message queuing	Simple queues
Table Storage	NoSQL key-value	Structured data

Database

Service	Use Case	Key Features
Azure SQL	Managed SQL Server	Hyperscale, serverless
PostgreSQL Flexible	Managed PostgreSQL	Zone redundant
CosmosDB	Multi-model NoSQL	Global distribution
Cache for Redis	In-memory cache	Managed Redis

Networking

Service	Use Case	Key Features
VNet	Virtual network	Private networking
Application Gateway	Layer 7 LB	WAF, SSL termination
Load Balancer	Layer 4 LB	Regional/Global
Front Door	Global CDN + LB	WAF, routing
Private Endpoint	Private connectivity	PaaS over VNet

VNet Architecture

Hub-Spoke Topology

code

┌─────────────────────────────────────────────────────────────────┐
│                          Hub VNet                               │
│                        10.0.0.0/16                              │
│                                                                 │
│  ┌─────────────────┐  ┌─────────────────┐  ┌────────────────┐  │
│  │ Gateway Subnet  │  │ Firewall Subnet │  │ Bastion Subnet │  │
│  │ 10.0.0.0/24     │  │ 10.0.1.0/24     │  │ 10.0.2.0/24    │  │
│  │                 │  │                 │  │                │  │
│  │ ┌─────────────┐ │  │ ┌─────────────┐ │  │ ┌────────────┐ │  │
│  │ │ VPN Gateway │ │  │ │ Azure       │ │  │ │ Bastion    │ │  │
│  │ └─────────────┘ │  │ │ Firewall    │ │  │ └────────────┘ │  │
│  └─────────────────┘  │ └─────────────┘ │  └────────────────┘  │
│                       └─────────────────┘                       │
└──────────────────────────────┬──────────────────────────────────┘
                               │ Peering
        ┌──────────────────────┼──────────────────────┐
        │                      │                      │
        ▼                      ▼                      ▼
┌───────────────┐    ┌───────────────┐    ┌───────────────┐
│ Spoke: Prod   │    │ Spoke: Dev    │    │ Spoke: Shared │
│ 10.1.0.0/16   │    │ 10.2.0.0/16   │    │ 10.3.0.0/16   │
│               │    │               │    │               │
│ App + Data    │    │ App + Data    │    │ DNS, AD DS    │
│ Subnets       │    │ Subnets       │    │ Monitoring    │
└───────────────┘    └───────────────┘    └───────────────┘

Terraform VNet

hcl

# Resource Group
resource "azurerm_resource_group" "main" {
  name     = "${var.project}-${var.environment}-rg"
  location = var.location
  tags     = local.common_tags
}

# Virtual Network
resource "azurerm_virtual_network" "main" {
  name                = "${var.project}-${var.environment}-vnet"
  location            = azurerm_resource_group.main.location
  resource_group_name = azurerm_resource_group.main.name
  address_space       = ["10.0.0.0/16"]
  tags                = local.common_tags
}

# Subnets
resource "azurerm_subnet" "app" {
  name                 = "app-subnet"
  resource_group_name  = azurerm_resource_group.main.name
  virtual_network_name = azurerm_virtual_network.main.name
  address_prefixes     = ["10.0.1.0/24"]

  delegation {
    name = "app-service-delegation"
    service_delegation {
      name    = "Microsoft.Web/serverFarms"
      actions = ["Microsoft.Network/virtualNetworks/subnets/action"]
    }
  }
}

resource "azurerm_subnet" "data" {
  name                 = "data-subnet"
  resource_group_name  = azurerm_resource_group.main.name
  virtual_network_name = azurerm_virtual_network.main.name
  address_prefixes     = ["10.0.2.0/24"]

  service_endpoints = [
    "Microsoft.Sql",
    "Microsoft.Storage",
    "Microsoft.KeyVault"
  ]
}

resource "azurerm_subnet" "aks" {
  name                 = "aks-subnet"
  resource_group_name  = azurerm_resource_group.main.name
  virtual_network_name = azurerm_virtual_network.main.name
  address_prefixes     = ["10.0.10.0/22"]
}

# Network Security Group
resource "azurerm_network_security_group" "app" {
  name                = "${var.project}-app-nsg"
  location            = azurerm_resource_group.main.location
  resource_group_name = azurerm_resource_group.main.name

  security_rule {
    name                       = "AllowHTTPS"
    priority                   = 100
    direction                  = "Inbound"
    access                     = "Allow"
    protocol                   = "Tcp"
    source_port_range          = "*"
    destination_port_range     = "443"
    source_address_prefix      = "*"
    destination_address_prefix = "*"
  }

  security_rule {
    name                       = "DenyAllInbound"
    priority                   = 4096
    direction                  = "Inbound"
    access                     = "Deny"
    protocol                   = "*"
    source_port_range          = "*"
    destination_port_range     = "*"
    source_address_prefix      = "*"
    destination_address_prefix = "*"
  }

  tags = local.common_tags
}

resource "azurerm_subnet_network_security_group_association" "app" {
  subnet_id                 = azurerm_subnet.app.id
  network_security_group_id = azurerm_network_security_group.app.id
}

Azure AD / Entra ID

Managed Identity

hcl

# User Assigned Managed Identity
resource "azurerm_user_assigned_identity" "app" {
  name                = "${var.project}-app-identity"
  resource_group_name = azurerm_resource_group.main.name
  location            = azurerm_resource_group.main.location
}

# Role Assignment - Storage
resource "azurerm_role_assignment" "storage" {
  scope                = azurerm_storage_account.main.id
  role_definition_name = "Storage Blob Data Contributor"
  principal_id         = azurerm_user_assigned_identity.app.principal_id
}

# Role Assignment - Key Vault
resource "azurerm_role_assignment" "keyvault" {
  scope                = azurerm_key_vault.main.id
  role_definition_name = "Key Vault Secrets User"
  principal_id         = azurerm_user_assigned_identity.app.principal_id
}

# Role Assignment - SQL
resource "azurerm_role_assignment" "sql" {
  scope                = azurerm_mssql_server.main.id
  role_definition_name = "SQL DB Contributor"
  principal_id         = azurerm_user_assigned_identity.app.principal_id
}

Service Principal (CI/CD)

hcl

# For CI/CD pipelines
resource "azuread_application" "cicd" {
  display_name = "${var.project}-cicd"
}

resource "azuread_service_principal" "cicd" {
  client_id = azuread_application.cicd.client_id
}

resource "azuread_service_principal_password" "cicd" {
  service_principal_id = azuread_service_principal.cicd.id
  end_date_relative    = "8760h"  # 1 year
}

# Grant Contributor to Resource Group
resource "azurerm_role_assignment" "cicd" {
  scope                = azurerm_resource_group.main.id
  role_definition_name = "Contributor"
  principal_id         = azuread_service_principal.cicd.object_id
}

AKS (Azure Kubernetes Service)

Production AKS Cluster

hcl

resource "azurerm_kubernetes_cluster" "main" {
  name                = "${var.project}-aks"
  location            = azurerm_resource_group.main.location
  resource_group_name = azurerm_resource_group.main.name
  dns_prefix          = var.project
  kubernetes_version  = var.kubernetes_version

  default_node_pool {
    name                = "system"
    node_count          = 3
    vm_size             = "Standard_D4s_v3"
    vnet_subnet_id      = azurerm_subnet.aks.id
    zones               = ["1", "2", "3"]
    enable_auto_scaling = true
    min_count           = 3
    max_count           = 10

    node_labels = {
      "nodepool" = "system"
    }
  }

  identity {
    type         = "UserAssigned"
    identity_ids = [azurerm_user_assigned_identity.aks.id]
  }

  network_profile {
    network_plugin    = "azure"
    network_policy    = "azure"
    load_balancer_sku = "standard"
    outbound_type     = "loadBalancer"
  }

  oidc_issuer_enabled       = true
  workload_identity_enabled = true

  azure_active_directory_role_based_access_control {
    managed                = true
    azure_rbac_enabled     = true
    admin_group_object_ids = [var.aks_admin_group_id]
  }

  key_vault_secrets_provider {
    secret_rotation_enabled  = true
    secret_rotation_interval = "2m"
  }

  oms_agent {
    log_analytics_workspace_id = azurerm_log_analytics_workspace.main.id
  }

  microsoft_defender {
    log_analytics_workspace_id = azurerm_log_analytics_workspace.main.id
  }

  tags = local.common_tags
}

# User Node Pool
resource "azurerm_kubernetes_cluster_node_pool" "user" {
  name                  = "user"
  kubernetes_cluster_id = azurerm_kubernetes_cluster.main.id
  vm_size               = "Standard_D8s_v3"
  zones                 = ["1", "2", "3"]
  enable_auto_scaling   = true
  min_count             = 2
  max_count             = 20
  vnet_subnet_id        = azurerm_subnet.aks.id

  node_labels = {
    "nodepool" = "user"
  }

  node_taints = []

  tags = local.common_tags
}

App Service

Web App with Slots

hcl

resource "azurerm_service_plan" "main" {
  name                = "${var.project}-plan"
  resource_group_name = azurerm_resource_group.main.name
  location            = azurerm_resource_group.main.location
  os_type             = "Linux"
  sku_name            = var.environment == "prod" ? "P2v3" : "B1"
}

resource "azurerm_linux_web_app" "main" {
  name                = "${var.project}-app"
  resource_group_name = azurerm_resource_group.main.name
  location            = azurerm_resource_group.main.location
  service_plan_id     = azurerm_service_plan.main.id
  https_only          = true

  identity {
    type         = "UserAssigned"
    identity_ids = [azurerm_user_assigned_identity.app.id]
  }

  site_config {
    always_on                = var.environment == "prod"
    http2_enabled            = true
    minimum_tls_version      = "1.2"
    ftps_state               = "Disabled"
    vnet_route_all_enabled   = true

    application_stack {
      node_version = "20-lts"
    }

    health_check_path = "/health"
  }

  app_settings = {
    WEBSITES_ENABLE_APP_SERVICE_STORAGE = "false"
    NODE_ENV                            = "production"
    KEY_VAULT_URI                       = azurerm_key_vault.main.vault_uri
  }

  connection_string {
    name  = "Database"
    type  = "SQLAzure"
    value = "@Microsoft.KeyVault(SecretUri=${azurerm_key_vault_secret.db_connection.id})"
  }

  virtual_network_subnet_id = azurerm_subnet.app.id

  logs {
    http_logs {
      file_system {
        retention_in_days = 7
        retention_in_mb   = 35
      }
    }
  }

  tags = local.common_tags
}

# Deployment Slot
resource "azurerm_linux_web_app_slot" "staging" {
  name           = "staging"
  app_service_id = azurerm_linux_web_app.main.id

  site_config {
    always_on           = false
    http2_enabled       = true
    minimum_tls_version = "1.2"

    application_stack {
      node_version = "20-lts"
    }
  }

  app_settings = azurerm_linux_web_app.main.app_settings

  tags = local.common_tags
}

Azure SQL

SQL Database

hcl

resource "azurerm_mssql_server" "main" {
  name                         = "${var.project}-sql"
  resource_group_name          = azurerm_resource_group.main.name
  location                     = azurerm_resource_group.main.location
  version                      = "12.0"
  administrator_login          = var.sql_admin_username
  administrator_login_password = random_password.sql.result
  minimum_tls_version          = "1.2"
  public_network_access_enabled = false

  azuread_administrator {
    login_username              = "AzureAD Admin"
    object_id                   = var.sql_aad_admin_object_id
    azuread_authentication_only = var.environment == "prod"
  }

  identity {
    type = "SystemAssigned"
  }

  tags = local.common_tags
}

resource "azurerm_mssql_database" "main" {
  name                 = var.database_name
  server_id            = azurerm_mssql_server.main.id
  collation            = "SQL_Latin1_General_CP1_CI_AS"
  max_size_gb          = 100
  sku_name             = var.environment == "prod" ? "GP_S_Gen5_4" : "Basic"
  zone_redundant       = var.environment == "prod"
  storage_account_type = "Zone"

  short_term_retention_policy {
    retention_days           = 7
    backup_interval_in_hours = 12
  }

  long_term_retention_policy {
    weekly_retention  = var.environment == "prod" ? "P4W" : null
    monthly_retention = var.environment == "prod" ? "P12M" : null
  }

  threat_detection_policy {
    state                      = "Enabled"
    email_account_admins       = "Enabled"
    retention_days             = 30
  }

  tags = local.common_tags
}

# Private Endpoint
resource "azurerm_private_endpoint" "sql" {
  name                = "${var.project}-sql-pe"
  location            = azurerm_resource_group.main.location
  resource_group_name = azurerm_resource_group.main.name
  subnet_id           = azurerm_subnet.data.id

  private_service_connection {
    name                           = "${var.project}-sql-psc"
    private_connection_resource_id = azurerm_mssql_server.main.id
    is_manual_connection           = false
    subresource_names              = ["sqlServer"]
  }

  private_dns_zone_group {
    name                 = "sql-dns-zone-group"
    private_dns_zone_ids = [azurerm_private_dns_zone.sql.id]
  }
}

Key Vault

Secure Secrets Management

hcl

resource "azurerm_key_vault" "main" {
  name                        = "${var.project}-kv"
  location                    = azurerm_resource_group.main.location
  resource_group_name         = azurerm_resource_group.main.name
  tenant_id                   = data.azurerm_client_config.current.tenant_id
  sku_name                    = "standard"
  soft_delete_retention_days  = 90
  purge_protection_enabled    = var.environment == "prod"
  enable_rbac_authorization   = true
  public_network_access_enabled = false

  network_acls {
    default_action             = "Deny"
    bypass                     = "AzureServices"
    virtual_network_subnet_ids = [azurerm_subnet.app.id]
  }

  tags = local.common_tags
}

resource "azurerm_key_vault_secret" "db_connection" {
  name         = "db-connection-string"
  value        = "Server=tcp:${azurerm_mssql_server.main.fully_qualified_domain_name};Database=${var.database_name};..."
  key_vault_id = azurerm_key_vault.main.id

  depends_on = [azurerm_role_assignment.kv_admin]
}

Storage Account

Secure Blob Storage

hcl

resource "azurerm_storage_account" "main" {
  name                            = "${replace(var.project, "-", "")}storage"
  resource_group_name             = azurerm_resource_group.main.name
  location                        = azurerm_resource_group.main.location
  account_tier                    = "Standard"
  account_replication_type        = var.environment == "prod" ? "GRS" : "LRS"
  account_kind                    = "StorageV2"
  min_tls_version                 = "TLS1_2"
  allow_nested_items_to_be_public = false
  public_network_access_enabled   = false

  blob_properties {
    versioning_enabled = true

    delete_retention_policy {
      days = 30
    }

    container_delete_retention_policy {
      days = 30
    }
  }

  network_rules {
    default_action             = "Deny"
    bypass                     = ["AzureServices"]
    virtual_network_subnet_ids = [azurerm_subnet.app.id]
  }

  identity {
    type = "SystemAssigned"
  }

  tags = local.common_tags
}

resource "azurerm_storage_container" "data" {
  name                  = "data"
  storage_account_name  = azurerm_storage_account.main.name
  container_access_type = "private"
}

# Lifecycle Management
resource "azurerm_storage_management_policy" "main" {
  storage_account_id = azurerm_storage_account.main.id

  rule {
    name    = "archive-old-blobs"
    enabled = true

    filters {
      blob_types   = ["blockBlob"]
      prefix_match = ["data/"]
    }

    actions {
      base_blob {
        tier_to_cool_after_days_since_modification_greater_than    = 30
        tier_to_archive_after_days_since_modification_greater_than = 90
        delete_after_days_since_modification_greater_than          = 365
      }
    }
  }
}

CLI Reference

bash

# Auth
az login
az account set --subscription "SUBSCRIPTION_NAME"
az account show

# Resource Groups
az group list
az group create --name mygroup --location eastus

# AKS
az aks get-credentials --resource-group mygroup --name mycluster
az aks list
az aks scale --resource-group mygroup --name mycluster --node-count 5

# App Service
az webapp list
az webapp deployment source config-zip --resource-group mygroup --name myapp --src app.zip
az webapp deployment slot swap --resource-group mygroup --name myapp --slot staging

# SQL
az sql db list --resource-group mygroup --server myserver
az sql db show-connection-string --server myserver --name mydb --client ado.net

# Storage
az storage blob list --container-name mycontainer --account-name mystorage
az storage blob upload --container-name mycontainer --file local.txt --name remote.txt

# Key Vault
az keyvault secret list --vault-name myvault
az keyvault secret show --vault-name myvault --name mysecret
az keyvault secret set --vault-name myvault --name mysecret --value "value"

Security Checklist

• Managed Identity instead of service principals
• RBAC with least privilege
• Private Endpoints for PaaS services
• Network Security Groups configured
• Key Vault for all secrets
• Diagnostic settings enabled
• Azure Defender/Security Center enabled
• Azure Policy for compliance
• TLS 1.2+ enforced everywhere

Integration

Works with:

•/terraform - Azure provider configuration
•/k8s - AKS deployments
•/devops - Azure DevOps pipelines
•/security - Azure security review