Understanding Azure Bicep What If Operations

Azure Bicep What If operations allow you to test and validate your infrastructure deployments without actually creating them.

This feature is especially useful for experimenting with different scenarios and configurations.

You can use the What If feature to estimate costs, identify potential issues, and ensure that your deployments meet the required specifications.

With What If, you can simulate the deployment process and receive feedback on any errors or warnings that might occur.

To preview changes before deploying a Bicep file, use what-if commands. This allows you to see the expected changes without actually making them.

You can use what-if commands to list seven different types of changes, including Create, Delete, Ignore, NoChange, NoEffect, Modify, and Deploy. These change types are crucial in understanding what will happen during a deployment.

Here are the different change types you might encounter:

After running the what-if operation, you'll see the expected changes and can confirm that you want the deployment to run.

Azure Bicep What-If limits are in place to prevent excessive processing. These limits include 500 nested templates, which is the maximum number of templates that can be expanded.

The maximum number of resource groups in a cross-resource group deployment is 800. This is a key consideration when planning your deployments.

A 5-minute time limit is also in place for expanding nested templates. This ensures that your deployments don't get stuck in an infinite loop.

Here are the Azure Bicep What-If limits summarized:

If any of these limits are reached, the remaining resources' change type is set to Ignore. This prevents further processing and allows you to review and adjust your deployments accordingly.

When working with Azure Bicep what-if, it's essential to evaluate and test your changes before deployment.

To preview changes, use the confirm switch parameter with the deployment command, allowing you to see the effects of your updates without actually deploying them.

This feature is particularly useful for identifying potential issues or unexpected outcomes, helping you refine your Bicep file before deployment.

You can set the command to a variable and then programmatically evaluate the what-if results, making it easier to automate and streamline your testing process.

By using the confirm switch parameter, you can respond to the deployment with a yes or no, allowing you to control the deployment process and ensure your changes meet your expectations.

Azure CLI is another tool you can use to preview changes before deploying a Bicep file. To do this, use the az deployment group what-if command for resource group deployments, az deployment sub what-if for subscription level deployments, az deployment mg what-if for management group deployments, or az deployment tenant what-if for tenant deployments.

You can use the --confirm-with-what-if switch (or its short form -c) to preview the changes and get prompted to continue with the deployment. For example, use az deployment group create --confirm-with-what-if or -c for resource group deployments.

The preceding commands return a text summary that you can manually inspect. To get a JSON object that you can programmatically inspect for changes, use the --no-pretty-print switch. For instance, use az deployment group what-if --no-pretty-print for resource group deployments.

If you want to return the results without colors, open your Azure CLI configuration file and set no_color to yes.

Here are the az deployment commands with the --confirm-with-what-if switch:

Azure API and Data Formats are designed to work seamlessly together. Azure API Management supports a wide range of data formats, including JSON, XML, and CSV.

When working with Azure Bicep, it's essential to consider the data formats that will be used. JSON is a popular choice due to its simplicity and flexibility.

Azure API Management also supports schema validation for JSON data, which helps ensure that the data is in the correct format. This is particularly useful when working with complex data structures.

Azure REST API is a powerful tool for deploying Azure resources, and it's essential to know how to use it effectively. You can deploy resources to different scopes, such as resource groups, subscriptions, management groups, and tenants.

For resource group deployments, you can use the Deployments - What If endpoint. This endpoint allows you to preview changes before deploying a Bicep file. You can use the -Whatif switch parameter to get a text summary of the changes.

Here are the endpoints you can use for different deployment scopes:

By using these endpoints, you can get a better understanding of the changes you're about to make and make more informed decisions about your Azure deployments.

The Result Format is a crucial aspect of Azure API and Data Formats. You have two options: FullResourcePayloads and ResourceIdOnly.

FullResourcePayloads returns a list of resources that will change and details about the properties that will change. This format is indicated by symbols: - Delete, + Create, ~ Modify.

ResourceIdOnly returns a list of resources that will change. This format is indicated by the symbol: ! Deploy.

You can control the level of detail returned about the predicted changes using the -WhatIfResultFormat parameter in PowerShell deployment commands, the ResultFormat parameter in programmatic object commands, or the --result-format parameter in Azure CLI.

Here are the two different output formats:

Resource ID only:

Conditional assignments allow you to set a value based on different conditions. This is useful when you want to make decisions in your Bicep template.

You can use a ternary operator to determine the value. It's similar to using an if-then-else statement. For example, if a boolean parameter `useSSD` is set to `true`, the storage account uses the `Premium_LRS` SKU; otherwise, it uses the `Standard_LRS` SKU.

The syntax for a ternary operator is `condition ? value_if_true : value_if_false`. In the example, it's `useSSD ? 'Premium_LRS' : 'Standard_LRS'`.

Here's a breakdown of how it works:

With conditional assignments, you can make your Bicep templates more flexible and adaptable to different scenarios.

Azure Bicep is a Domain Specific Language (DSL) for declaring and deploying Azure resources. It was created to simplify the process of writing code.

Azure Bicep has a clearer and simpler syntax than Azure ARM. It offers superior support for modularity and reusing code.

In many ways, Azure Bicep can be thought of as a revised version of Azure ARM. It was made after modifying Azure ARM.

The current version 0.3 is considered to be the latest release and stable for use. Any workload from Azure ARM can be done efficiently in Azure Bicep.