Azure Functions Premium Plan

The Azure Functions Premium plan offers key features of the App Service plan for Functions, such as virtual network connectivity and always-on capabilities, without requiring you to manage underlying infrastructure. This plan is ideal for production workloads that require predictable performance and lower latency.

Key Features and Benefits

Always On

Functions are pre-warmed and ready to respond to events, eliminating cold starts for your most critical workloads.

Virtual Network Integration

Connect your functions to your virtual networks for secure access to resources and private endpoints.

Predictable Cost

Based on reserved instances, offering more predictable pricing than the Consumption plan for high-traffic scenarios.

Enhanced Instance Sizing

Choose from a variety of instance sizes with more CPU and memory options to meet demanding performance requirements.

Automatic Scaling

Scales automatically based on workload, ensuring high availability and responsiveness.

Managed Identity & Private Endpoints

Securely access other Azure resources using managed identities and connect to services via private endpoints.

When to Use the Premium Plan

The Premium plan is a strong choice for scenarios such as:

Production workloads with high-throughput requirements.
Functions that need to avoid cold starts for an optimal user experience.
Applications requiring VNet integration for secure resource access.
Workloads with predictable resource demands where upfront cost optimization is desired.

Instance Types and Pricing

The Premium plan offers several instance types, each with different CPU and memory configurations. Pricing is based on the number and type of instances reserved. For detailed pricing, please refer to the Azure Functions Pricing page.

Configuration

Creating a Premium Plan Function App

When creating a new Function App in the Azure portal, select "Premium" under the "Plan type" and then choose your desired plan tier (e.g., EP1, EP2, EP3).


# Example using Azure CLI to create a Premium plan function app
az functionapp create \
  --resource-group MyResourceGroup \
  --name MyPremiumFunctionApp \
  --storage-account MyStorageAccount \
  --consumption-plan-location westus2 \
  --runtime dotnet \
  --functions-version 3 \
  --plan-type Premium \
  --sku EP1

Configuring "Always On"

For the Premium plan, the "Always On" setting is enabled by default. You can verify or adjust this setting in the Azure portal under your Function App's configuration.

Considerations

Performance Tuning: While the Premium plan mitigates cold starts, ensure your function code is optimized for performance. Monitor execution times and resource utilization to identify potential bottlenecks.

The Premium plan provides a balance between the scalability of the Consumption plan and the control of the App Service plan. Carefully evaluate your application's needs to determine if this plan is the right fit.