Introduction

When your app needs to handle more users or tasks, it must grow smoothly without breaking. Azure Functions can automatically add more instances to handle extra work, so your app stays fast and reliable.

When your app suddenly gets many users and you want it to respond quickly without delays

When you have background jobs that run at different times and need more computing power only when busy

When you want to save money by only using resources when your app is active

When you want your app to handle unpredictable workloads without manual setup

When you want to avoid your app crashing because it cannot handle too many requests at once

Commands

This command creates a new Azure Function App using the consumption plan, which automatically scales based on workload.

Terminal

az functionapp create --resource-group example-group --consumption-plan-location eastus --runtime dotnet --functions-version 4 --name example-functionapp --storage-account examplestorageacct

Expected OutputExpected

{ "id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/example-group/providers/Microsoft.Web/sites/example-functionapp", "location": "eastus", "name": "example-functionapp", "resourceGroup": "example-group", "type": "Microsoft.Web/sites" }

→

--consumption-plan-location - Specifies the region where the function app will run and scale automatically

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--runtime - Sets the programming language runtime for the function app

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--functions-version - Defines the version of Azure Functions runtime to use

This command shows the current plan details of the function app to confirm it uses the consumption plan that supports automatic scaling.

Terminal

az functionapp plan show --name example-functionapp --resource-group example-group

Expected OutputExpected

{ "name": "example-functionapp", "location": "eastus", "sku": { "name": "Y1", "tier": "Dynamic" }, "kind": "functionapp", "status": "Ready" }

This command ensures the function app is not always on, allowing it to scale down to zero when idle, saving costs.

Terminal

az functionapp config set --name example-functionapp --resource-group example-group --always-on false

Expected OutputExpected

{ "alwaysOn": false }

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--always-on - Controls whether the function app stays running all the time or scales down when idle

This command retrieves the current state and configuration of the function app to verify settings.

Terminal

az functionapp show --name example-functionapp --resource-group example-group

Expected OutputExpected

{ "name": "example-functionapp", "state": "Running", "hostNames": [ "example-functionapp.azurewebsites.net" ], "serverFarmId": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/example-group/providers/Microsoft.Web/serverfarms/example-functionapp" }

Key Concept

If you remember nothing else from this pattern, remember: Azure Functions on the consumption plan automatically add or remove instances to match workload, so your app stays responsive and cost-efficient.

Common Mistakes

Creating the function app with a fixed pricing plan instead of the consumption plan

Fixed plans do not scale automatically and can lead to higher costs or poor performance under load

Use the consumption plan by specifying --consumption-plan-location when creating the function app

Setting always-on to true in a consumption plan function app

Always-on prevents the app from scaling down to zero, increasing costs unnecessarily

Set always-on to false to allow scaling down when idle

Not verifying the function app plan after creation

You might think the app is on the consumption plan but it could be on a fixed plan, causing unexpected behavior

Run az functionapp plan show to confirm the plan type

Summary

Create an Azure Function App using the consumption plan to enable automatic scaling.

Check the function app plan to ensure it supports dynamic scaling.

Set always-on to false to allow the app to scale down when idle and save costs.

Verify the function app state and configuration after setup.