03 - Configuration, Secrets, and Dapr¶

This step configures runtime settings in Azure Container Apps for your .NET application, including environment variables, secrets, KEDA scaling rules, and Dapr sidecar options.

flowchart TD
    INET[Internet] -->|HTTPS| CA["Container App\nConsumption\nLinux .NET 8"]

    subgraph VNET["VNet 10.0.0.0/16"]
        subgraph ENV_SUB["Environment Subnet 10.0.0.0/23\nDelegation: Microsoft.App/environments"]
            CAE[Container Apps Environment]
            CA
        end
        subgraph PE_SUB["Private Endpoint Subnet 10.0.2.0/24"]
            PE_ACR[PE: ACR]
            PE_KV[PE: Key Vault]
            PE_ST[PE: Storage]
        end
    end

    PE_ACR --> ACR[Azure Container Registry]
    PE_KV --> KV[Key Vault]
    PE_ST --> ST[Storage Account]

    subgraph DNS[Private DNS Zones]
        DNS_ACR[privatelink.azurecr.io]
        DNS_KV[privatelink.vaultcore.azure.net]
        DNS_ST[privatelink.blob.core.windows.net]
    end

    PE_ACR -.-> DNS_ACR
    PE_KV -.-> DNS_KV
    PE_ST -.-> DNS_ST

    CA -.->|System-Assigned MI| ENTRA[Microsoft Entra ID]
    CAE --> LOG[Log Analytics]
    CA --> AI[Application Insights]

    style CA fill:#107c10,color:#fff
    style VNET fill:#E8F5E9,stroke:#4CAF50
    style DNS fill:#E3F2FD

Configuration Flow¶

graph TD
    ENV[Env Vars] --> ACA[Container App]
    SEC[Secrets] --> ACA
    DAPR[Dapr] --> ACA
    ACA --> APP[ASP.NET Core App]
    APP --> KESTREL[Kestrel Server]

Prerequisites¶

• Completed 02 - First Deploy to Azure Container Apps
• A running Container App (deployed in 02 - First Deploy)

Step-by-step¶

1. Set standard variables (reuse Bicep outputs from Step 02)

RG="rg-dotnet-guide"
DEPLOYMENT_NAME="main"

APP_NAME=$(az deployment group show \
  --name "$DEPLOYMENT_NAME" \
  --resource-group "$RG" \
  --query "properties.outputs.containerAppName.value" \
  --output tsv)

ACR_NAME=$(az deployment group show \
  --name "$DEPLOYMENT_NAME" \
  --resource-group "$RG" \
  --query "properties.outputs.containerRegistryName.value" \
  --output tsv)

1. Set environment variables

ASP.NET Core automatically reads environment variables into its configuration system.

az containerapp update \
  --name "$APP_NAME" \
  --resource-group "$RG" \
  --set-env-vars "Logging__LogLevel__Default=Information" "FeatureManagement__NewUI=true"

???+ example "Expected output"

{
  "name": "<your-app-name>",
  "provisioningState": "Succeeded"
}

1. Store and reference a secret

az containerapp secret set \
  --name "$APP_NAME" \
  --resource-group "$RG" \
  --secrets "db-connection-string=Server=tcp:sql.database.windows.net;Database=mydb;"

???+ example "Expected output"

Containerapp must be restarted in order for secret changes to take effect.

[
  {
    "name": "db-connection-string"
  }
]

Map the secret to an environment variable:

az containerapp update \
  --name "$APP_NAME" \
  --resource-group "$RG" \
  --set-env-vars "ConnectionStrings__DefaultConnection=secretref:db-connection-string"

1. Configure KEDA HTTP autoscaling

az containerapp update \
  --name "$APP_NAME" \
  --resource-group "$RG" \
  --min-replicas 0 \
  --max-replicas 10 \
  --scale-rule-name "http-scale" \
  --scale-rule-type "http" \
  --scale-rule-http-concurrency 50

???+ example "Expected output"

{
  "name": "<your-app-name>",
  "provisioningState": "Succeeded"
}

1. Enable Dapr sidecar

az containerapp dapr enable \
  --name "$APP_NAME" \
  --resource-group "$RG" \
  --dapr-app-id "dotnet-api" \
  --dapr-app-port 8000

???+ example "Expected output"

{
  "appId": "dotnet-api",
  "appPort": 8000,
  "appProtocol": "http",
  "enabled": true
}

Verify configuration in Azure Portal¶

[Observed] ca-dotnet-d38538. Container App. Containers. Refresh. Send us your feedback. Container. Properties. Environment variables. Health probes. Volume mounts. Container details. Name. ca-dotnet-d38538. Image source. Azure Container Registry. Docker Hub or other registries. Authentication. Managed identity. Secrets. Identity. System assigned. Subscription. Visual Studio Enterprise Subscription. Registry. acrbasicsd38538.azurecr.io. Image. dotnet-sample. Image tag. v1. Command override. Arguments override. Application. Revisions and replicas. Containers. Scale. Volumes. Settings. Networking. Ingress. Custom domains. CORS. Security. Monitoring. Log stream. Logs. Console. Alerts. Metrics.

[Inferred] The Environment variables tab appears to map to the same name=value pairs supplied via --set-env-vars in Step-by-step. The Image field value dotnet-sample and Image tag value v1 appear consistent with the --image reference set across Step-by-step. The Registry field value acrbasicsd38538.azurecr.io is consistent with the ACR login server referenced throughout Step-by-step. The left-navigation entry Scale is consistent with the --scale-rule-* levers configurable via the operations referenced in Step-by-step.

[Not Proven] Additional configuration detail and runtime parameter detail are not visible on this view.

.NET example: read config safely¶

ASP.NET Core's IConfiguration makes it easy to read these values.

// In Program.cs or a Controller
var logLevel = configuration["Logging:LogLevel:Default"];
var isNewUIEnabled = configuration.GetValue<bool>("FeatureManagement:NewUI");
var connectionString = configuration.GetConnectionString("DefaultConnection");

Advanced Topics¶

• Managed Identity: Use DefaultAzureCredential from the Azure Identity SDK to access Key Vault without managing client secrets.
• KEDA Scalers: Explore .NET specific scalers like azure-servicebus or rabbitmq for background processing.
• Dapr SDK: Use the Dapr.Client NuGet package for advanced Dapr features like state store and pub/sub.

See Also¶

• 04 - Logging, Monitoring, and Observability
• .NET Runtime Reference
• Recipes Index

Sources¶

• Configuration in ASP.NET Core (Microsoft Learn)
• Manage secrets in Azure Container Apps (Microsoft Learn)