Azure Functions Docker: From Development to Deployment

Developing Azure Functions locally is a breeze with the Azure Functions Core Tools, which allows you to run and test your functions directly in Visual Studio Code.

To create a Docker image for your Azure Function, you'll need to use a Dockerfile, which is a text file that contains instructions for building an image.

The Azure Functions Core Tools provides a command to create a Docker image, `func dockerize`, which packages your function code and dependencies into a container.

You can then push this image to a container registry like Azure Container Registry (ACR) for use in your Azure Functions deployment.

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To get started with Azure Functions Docker, you'll need to meet some prerequisites. First, you'll need to install the .NET 8.0 SDK, Azure Functions Core Tools version 4.0.5198 or later, and Azure CLI version 2.4 or later.

You'll also need to install a version of Node.js that is supported by Azure Functions, as well as a version of Python that is supported by Azure Functions. Additionally, you'll need to install a version of the Java Developer Kit that is supported by Azure Functions, along with Apache Maven version 3.0 or above.

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A Docker ID and Docker running on your local computer are also required. If you don't have a Docker ID, you can create a Docker account.

Here are the specific versions you'll need for each language:

Make sure you have an Azure account with an active subscription, and create one for free if you don't already have one.

Creating a containerized function app is easier than ever with Azure Functions. You can create a function app in a local container using the Azure Functions extension for Visual Studio Code, which creates a Dockerfile for your code project.

To create a containerized function app, you can use the Docker build command to create an image of your functions from the project in the local directory. This process is explained in the section "Create your function app in a container".

You can also use the Azure CLI to create a function app from an image in a container registry and configure it with a connection string to Azure Storage. This involves creating a function app using the az functionapp create command, which requires specifying the name of the function app, the storage account, and the image to use.

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Here are the steps to create a function app using the Azure CLI:

Azure Functions on Container Apps provides a unified platform for building event-driven, cloud-native apps, with the flexibility to run functions along with other microservices, APIs, websites, workflows, or any container-hosted programs. You can leverage the Functions programming model and write code using your preferred programming language or framework that Azure Functions supports.

Here are the key features of Azure Functions on Container App Environment:

You can host your containerized function app on Azure Container Apps and set up continuous deployment from a source code repository.

There are two ways to set up continuous deployment: Azure Pipelines or GitHub Actions. You can't continuously deploy containers based on image changes in a container registry.

To use continuous deployment, you need to deploy your container in an App Service plan instead of an Elastic Premium plan. This is because webhook-based deployment isn't supported in Elastic Premium plans.

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You can configure continuous deployment using either Azure Pipelines or GitHub Actions.

Here are the steps to enable continuous deployment:

With these steps, Azure Functions will redeploys your image whenever you update it in Docker Hub.

Managed Identity is now supported for Azure Functions on Azure Container apps, making it easier to access other Microsoft Entra protected resources.

This means your functions app can use a managed identity from Microsoft Entra ID to access Azure Key Vault without needing to provision or rotate any secrets.

Managed Identities can be used for triggers & bindings, storage account, pull images from Azure Container Registry ACR or fetch secrets from Azure Key Vault.

With both system and user-assigned managed identity enabled, you have more flexibility to choose the approach that works best for your project.

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Managed Identity is now supported for Azure Functions on Azure Container apps. This allows your functions app to easily access other Microsoft Entra protected resources.

A managed identity from Microsoft Entra ID eliminates the need to provision or rotate any secrets. This makes it a more secure option.

Managed Identities can be used for triggers & bindings, storage account, pull images from Azure Container Registry ACR or fetch secrets from Azure Key Vault. This flexibility makes it a valuable tool for developers.

Support for both system and user-assigned managed identity is enabled. This gives developers more options for how to implement managed identity in their apps.

Enabling SSH connections is a crucial step in securing your container. SSH enables secure communication between a container and a client.

To enable SSH, you can use Azure Functions' base image that has SSH already enabled. This makes it easy to connect to your container using App Service Advanced Tools (Kudu).

You only need to edit your Dockerfile, then rebuild and redeploy the image. This simple process allows you to connect to the container through the Advanced Tools (Kudu).

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Continuous deployment is a game-changer for Azure Functions Docker users. You can set up continuous deployment from a source code repository using either Azure Pipelines or GitHub Actions. This means your function app will automatically update whenever you make changes to your code.

To enable continuous deployment, you'll need to use the az functionapp deployment container config command. This command enables continuous deployment and returns the deployment webhook URL, which you can use to trigger updates to your function app.

Here are the steps to follow:

With this setup, Azure Functions will automatically redeploy your image whenever you update it in Docker Hub. This is especially useful if you're using an Elastic Premium plan, as you won't need to manually restart your app after making updates.

Now that you've learned about Azure Functions and Docker, it's time to take your skills to the next level. Working with custom containers is a great way to extend the capabilities of your Azure Functions.

You can create custom containers using Docker, which allows you to package your application and its dependencies into a single container that can be easily deployed to Azure. This gives you more control over the environment in which your function runs.

To get started, make sure you have Docker installed on your machine. You can then use the Azure Functions CLI to create a new function that uses a custom container. This will allow you to write your function code and package it into a container, which can then be deployed to Azure.

Azure Functions supports a variety of triggers and bindings, which enable your function to interact with other Azure services and external systems. By using custom containers, you can extend the capabilities of these triggers and bindings to include support for other services or systems.

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When choosing a development language for Azure Functions, you should select it at the top of the article. This will ensure that Core Tools generates a Dockerfile for your project using the most up-to-date version of the correct base image for your functions language.

Curious to learn more? Check out: Azure Language Service

You should regularly update your container from the latest base image and redeploy from the updated version of your container. For more information, see Creating containerized function apps.

Azure Functions can be used for a variety of scenarios, including reacting to events from HTTP, Kafka, Event Hubs, Service Bus, and Storage Queue, and invoking another web or Spring-based API.

Here are some specific use cases and scenarios that can be deployed on Azure Functions on Azure Container Apps:

To choose your development language, you can use Azure Functions tools to create your project code as a function app in a Docker container.

You'll select your language of choice at the top of the process, which will determine the correct base image for your functions language.

Core Tools automatically generates a Dockerfile for your project that uses the most up-to-date version of the correct base image for your functions language.

You should regularly update your container from the latest base image and redeploy from the updated version of your container.

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In a world where technology is constantly evolving, it's essential to understand the different scenarios where Azure Functions and Azure Container Apps can be deployed. Azure Functions can be used to react to events from various sources, such as Http, Kafka, Event hubs, Service Bus, and Storage Queue.

These events can trigger another web or Spring-based API running in the Container App environment. This allows for seamless integration and scalability as the events increase.

One of the most common scenarios is using Azure Functions to create a web services backend with event-based execution requirements or authentication APIs that trigger during login or authorization events.

Here are some real-world examples of scenarios where Azure Functions and Azure Container Apps can be deployed:

These scenarios highlight the versatility and flexibility of Azure Functions and Azure Container Apps. By leveraging these technologies, businesses can create scalable and efficient solutions that meet their unique needs.

To set up your Azure resources, you'll need to create three key items: a resource group, a storage account, and a function app. A resource group is a logical container for related resources, and it's essential to create one to organize your Azure resources.

You can create a resource group using the Azure CLI or PowerShell. To do this, sign in to your Azure account using the az login command or the Connect-AzAccount cmdlet. Then, create a resource group named AzureFunctionsContainers-rg in your chosen region by using the az group create command or the New-AzResourceGroup cmdlet.

A storage account is used to maintain state and other information about your functions. You can create a general-purpose storage account in your resource group and region using the az storage account create command or the New-AzStorageAccount cmdlet. Be sure to choose a unique and descriptive name for your storage account, as it must contain 3 to 24 characters and only numbers and lowercase letters.

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To create a function app, you need to create a Premium plan for Azure Functions. This plan can scale as needed and is suitable for hosting your function app. You can create a Premium plan named myPremiumPlan in the Elastic Premium 1 pricing tier (--sku EP1), in your region, and in a Linux container using the az functionapp plan create command or the New-AzFunctionAppPlan cmdlet.

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Updating your Azure Functions Docker image is a straightforward process. You can modify the image with a new version tag and build it using the command `/image_name:`, following the format for Docker Hub-based images.

If you need to update the workload profile type, use the same command with the new profile type specified. This will ensure your function's container app image is updated correctly.

To avoid cold start problems, set the minimum replicas in your functions container app configuration. This will help ensure your function is always running and ready to handle requests.

Verifying your deployment is also easy. Use the `az aks browse` command to start the Kubernetes web dashboard. Once you're in the dashboard, look for the namespace "azure-functions" and check that a pod has been deployed successfully with your container.

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