Since November 2019, ARM templates no longer have to be pure JSON. Several other constructs are now allowed to make working with ARM templates easier.

To comment the rest of a line, // is used, or to comment a block, the /* */ notation is used. This makes the following snippets both valid as part of an ARM template:

{
  “appServiceName”: {
    // this is a single line comment
    “type”: “string” 
      /*
       This is a multi-line comment
     */
    } 
}

Another deviation from JSON is that ARM templates allow for a multi-line string. When using these from the Azure CLI, this has to be enabled by specifying the --handle-extended-json-format switch. To use these and other new features, a new JSON schema has to be referenced from the template. This schema is https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#.

Also, a new command has been introduced to show what changes would be made if a template wer be applied. This command is still in preview and called New-AzDeploymentWhatIf. A link to the documentation is included at the end of this chapter.

While ARM templates are the preferred approach in Azure for managing infrastructure, there are scenarios where it might not fit. In these cases, Azure Automation can be an alternative. Azure Automation is discussed in the next section.