/azure-prepare

Container Apps Networking

VNet integration, ingress configuration, custom domains, and TLS for Container Apps.

Ingress Modes

Bicep — External Ingress

configuration: {
  ingress: {
    external: true
    targetPort: 8080
    transport: 'auto'
    allowInsecure: false
  }
}

Bicep — Internal Ingress

configuration: {
  ingress: {
    external: false
    targetPort: 8080
  }
}

💡 Tip: Internal apps get a *.internal.<env-default-domain> FQDN. This is accessible from within the Container Apps environment and, when the environment is VNet-injected, also from the VNet.

VNet Integration

Container Apps run inside an environment that can be injected into a VNet subnet.

Subnet Requirements

Bicep — VNet-Integrated Environment

resource subnet 'Microsoft.Network/virtualNetworks/subnets@2023-11-01' = {
  parent: vnet
  name: 'container-apps-subnet'
  properties: {
    addressPrefix: '10.0.16.0/27'
    delegations: [
      {
        name: 'Microsoft.App.environments'
        properties: { serviceName: 'Microsoft.App/environments' }
      }
    ]
  }
}

resource env 'Microsoft.App/managedEnvironments@2024-03-01' = {
  name: envName
  location: location
  properties: {
    vnetConfiguration: {
      infrastructureSubnetId: subnet.id
      internal: false // true for internal-only environment
    }
  }
}

⚠️ Warning: VNet configuration is set at environment creation and cannot be changed afterward. Plan your network topology before creating the environment.

Custom Domains

Steps

1. Add a CNAME or A record pointing to the Container App's FQDN or static IP
2. Bind the custom domain to the Container App
3. Configure a managed or custom TLS certificate

# Register custom domain (hostname only — no cert provisioned yet)
az containerapp hostname add -n $APP -g $RG --hostname app.contoso.com

# Bind managed certificate (provisions and attaches TLS cert)
az containerapp hostname bind -n $APP -g $RG \
  --hostname app.contoso.com \
  --environment $ENV_NAME \
  --validation-method CNAME

DNS Configuration

💡 Tip: Use az containerapp show -n $APP -g $RG --query properties.configuration.ingress.fqdn to get the target FQDN for DNS records.

TLS Configuration

Managed Certificates

Azure automatically provisions and renews TLS certificates for custom domains — no manual cert management required.

⚠️ Prerequisites: Managed certificates require the app to be externally reachable with valid public DNS (CNAME or HTTP validation). They do not work for internal environments or apps behind private DNS. For private/internal scenarios, bring your own certificate via az containerapp ssl upload.

IP Restrictions

⚠️ Warning: IP restriction rules are evaluated in array order (first match wins). The priority field does not exist in the Container Apps API — order your rules carefully in the array.

Allow-only rules implicitly deny all traffic not matching any rule. Deny-only rules implicitly allow all other traffic.

configuration: {
  ingress: {
    external: true
    targetPort: 8080
    ipSecurityRestrictions: [
      {
        name: 'allow-office'
        action: 'Allow'
        ipAddressRange: '203.0.113.0/24'
        description: 'Office network'
      }
      {
        name: 'allow-vpn'
        action: 'Allow'
        ipAddressRange: '198.51.100.0/24'
        description: 'VPN gateway'
      }
    ]
  }
}

Network Topology Summary

⚠️ Warning: An internal environment has no public IP. You need VPN, ExpressRoute, or a jump box to reach apps in an internal environment.