Update Azure Function Runtime Version with Minimal Downtime

Updating the Azure Function Runtime Version with minimal downtime is crucial for maintaining high availability and performance.

To minimize downtime, you can use the Azure Function Runtime Version Swap feature. This feature allows you to swap the runtime version of your Azure Functions with minimal interruption to your application.

The Swap feature works by creating a new instance of the updated runtime version, and then switching traffic to the new instance once it's available. This process can be done in just a few minutes, depending on the size of your function app and the amount of traffic it receives.

Azure Functions provides a built-in swap feature that can be used to update the runtime version with minimal downtime.

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To upgrade the runtime version for your Azure functions, you'll need to follow a few steps.

Choose the Function runtime settings tab and select the latest runtime version supported by the Microsoft Azure Function App from the Runtime version dropdown list. Choose Save to apply the changes.

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You'll need to repeat these steps for each Azure Function App you want to configure, deployed in the selected Azure subscription.

Run the functionapp config appsettings set command using the name of the Azure Function App as the identifier parameter to set the FUNCTIONS_EXTENSION_VERSION application setting to the latest runtime version supported by the Microsoft Azure Function App.

The command output should return the new application settings configured for the selected Azure Function App.

Repeat the process for each Azure Function App you want to configure, available within the current subscription.

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Before making any changes to your Azure Function, it's essential to plan ahead. You can't update the runtime version of an Azure Function that's currently in use, so make sure to create a new function with the desired runtime version and then switch to it.

Azure Function runtime versions are backwards compatible, so you can update to a newer version without worrying about breaking your existing code. However, it's still crucial to test your function thoroughly after the update.

To prepare for the update, take a backup of your existing Azure Function's code and configuration. This will ensure that you can easily revert to the previous version if something goes wrong during the update process.

You can update the runtime version of an Azure Function by creating a new function with the desired version and then switching to it.

To update your Azure Function runtime to version 4, you'll need to use the Azure CLI and execute a specific command. The command is: az functionapp config update --set FUNCTIONS_EXTENSION_VERSION=~4.

You can't simply select runtime 4 from the drop-down box in many scenarios. Runtime 4 is missing from the available choices.

To update your function app runtime to version 4, you need to specify the name of your Azure Function, Resource Group, and the runtime version you need to set. For example, ~4.

After executing the command, you'll see that your function app configuration is updated, but a warning is displayed. The warning message is: "Your app is pinned to an unsupported runtime version for 'dotnet'. For better performance, we recommend using one of our supported versions instead."

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You can check the runtime stack version of your function app by accessing the Azure Resource Explorer. Browse to your subscription/resource group/providers/Microsoft.Web/Sites/Your Function App/Config/web.

If your function app is running on .NET Framework 4 stack, you'll need to update it to .NET 6.0. The platform didn't update it automatically to avoid breaking customer's applications.

You can use the Azure CLI to update the "netFrameworkVersion" in the app config for your function app. The command is: az functionapp config update --set netFrameworkVersion=v6.0.

After updating the "netFrameworkVersion", the warning message will disappear, and your function app will be running on runtime V4.

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You can upgrade your Azure Functions to .NET 8 by following a step-by-step guide.

After making changes to your csproj file, it should look similar to this:.net6For DevelopersAzureAzure Function Apps.net8.

To change the Azure Function Runtime to Dotnet-Isolated, log in to the Azure Portal and change the FUNCTIONS_WORKER_RUNTIME Configuration value from dotnet to dotnet-isolated.

You can also update the runtime version using Azure CLI. To update the runtime to version 4, execute the following command: az functionapp config update --set FUNCTIONS_EXTENSION_VERSION=~4 --name FUNCTION_APP --resource-group RESOURCE_GROUP.

The runtime version of your Azure Function app is determined by the FUNCTIONS_EXTENSION_VERSION setting. If you need to update to version 4, you may need to use Azure CLI to set the runtime version to custom (~4).

Here are the steps to update the runtime to version 4:

Note: Function V4 runtime requires .NET 6.0, so you may need to upgrade your function app to use this version.

To ensure a smooth transition to a new runtime version, it's essential to test your Azure Function thoroughly before making the switch.

You can use the Azure Function's built-in testing features, such as the "Test" button in the Azure portal, to verify that your function is working as expected.

Always make a backup of your function's configuration and code before updating the runtime version.

Test your function's dependencies, such as NuGet packages, to ensure they are compatible with the new runtime version.

Azure Function's runtime version update can be done through the Azure portal or using Azure CLI.

Before updating the runtime version, make sure to check the Azure Function's documentation for any known issues or compatibility problems.

Regularly reviewing and updating your Azure Function's configuration and code can help prevent issues when updating the runtime version.

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