20 ARM Template Interview Questions and Answers

An ARM template is a JSON file that defines the infrastructure and configuration for a Microsoft Azure solution. ARM templates are used to deploy and manage Azure resources. If you are applying for a position that involves working with Azure, you may be asked questions about ARM templates during your interview. In this article, we review some of the most common ARM template questions and provide tips on how to answer them.

ARM Template Interview Questions and Answers

Here are 20 commonly asked ARM Template interview questions and answers to prepare you for your interview:

1. What are ARM templates?

ARM templates are JSON files that can be used to deploy and manage Azure resources. They provide a declarative way to define your infrastructure, making it easy to version control and automate the deployment of your Azure resources.

2. Can you explain the basic structure of an ARM template?

The basic structure of an ARM template is a JSON file that contains six top-level sections: parameters, variables, resources, outputs, and functions. The parameters section is where you define all of the input values that will be used in the template. The variables section is where you can define values that will be used throughout the template. The resources section is where you define all of the Azure resources that will be created or deployed. The outputs section is where you can define values that will be outputted after the template has been deployed. The functions section is where you can define custom functions that can be used throughout the template.

3. How do you use parameters in an ARM template to configure resources?

You can use parameters in an ARM template to configure resources by adding the parameters section to the template, and then adding a reference to the parameter in the resource configuration. The parameter will be replaced with the actual value when the template is deployed.

4. What is the difference between a parameter and a variable?

A parameter is a value that is passed in to an ARM template when it is deployed. A variable is a value that is defined within the ARM template itself.

5. Is it possible to iterate over an array in an ARM template? If yes, how would you do it?

Yes, it is possible to iterate over an array in an ARM template. You can do this using the “copy” element. The “copy” element will allow you to iterate over an array and create multiple resources from a single template.

6. Why are aliases useful when using ARM templates?

Aliases are useful when using ARM templates because they provide a way to give a name to a specific resource in the template. This can be helpful when you want to reference the same resource multiple times in the template, or if you want to make the template easier to read and understand.

7. Is it possible to deploy multiple virtual machines from one ARM template? If yes, then how?

Yes, it is possible to deploy multiple virtual machines from one ARM template. You can do this by using the “copy” element in the template. The “copy” element allows you to specify how many times a certain section of the template should be repeated. So, if you wanted to deploy three virtual machines, you would use the “copy” element to repeat the section of the template that defines a virtual machine three times.

8. What is the default order of precedence for different values given for a specific property in an ARM template?

The order of precedence, from highest to lowest, is:

1. Local values
2. Secret values
3. Environment variables
4. Resource Manager templates

9. Can you explain what resource groups are? When should they be used?

Resource groups are a way of logically grouping together related resources in Azure. This can be helpful for managing and deploying resources, as well as for billing purposes. Resource groups should be used whenever you have a set of resources that you want to manage or deploy together.

10. What are some common troubleshooting tips that can help resolve issues with ARM templates?

There are a few common troubleshooting tips that can help resolve issues with ARM templates:

– Make sure that the template is valid JSON. You can use a tool like JSONLint to validate the template.
– Make sure that all of the parameters are correctly filled in. You can use the Azure Portal to check the values of the parameters that are being used.
– Make sure that the template is using the correct API version for the resources that are being used. You can find the API versions for each resource type in the Azure Resource Manager documentation.

11. What’s the best way to reference Azure Resource Manager (ARM) Outputs in PowerShell or CLI automation scripts?

The best way to reference Azure Resource Manager (ARM) Outputs in PowerShell or CLI automation scripts is to use the Get-AzureRmResource cmdlet. This cmdlet will return all of the outputs for a given resource.

12. What sort of error messages can we get while deploying ARM templates?

The most common error message you’ll see when deploying ARM templates is the “deployment failed” message. This usually indicates that there was a problem with the template itself, and that the template could not be deployed successfully. Other error messages can include “resource not found” or “resource already exists”, which usually indicate a problem with the resources that are being referenced in the template.

13. What are nested templates?

Nested templates are ARM templates that are called from within other ARM templates. Nested templates can be used to modularize your ARM template deployments, and they can also be used to deploy resources that are not supported by the main ARM template.

14. How does locking work in ARM templates?

Locking in ARM templates allows you to lock certain resources so that other users cannot make changes to them. This can be useful if you want to make sure that a certain resource is not accidentally deleted or modified. To lock a resource, you can use the “lock” property in the resource definition.

15. What’s the difference between a template and a deployment in context with Azure Resource Manager?

A template is a JSON file that defines one or more resources that you want to deploy to Azure. A deployment is an instance of a template that you have deployed to Azure.

16. Is there any limit on the number of ARM deployments per resource group? If yes, then why?

There is no limit on the number of ARM deployments per resource group. The main reason for this is that each deployment is isolated from the others, so there is no risk of one deployment affecting the others.

17. Can you explain what concurrency and throttling mean in the context of ARM templates?

Concurrency and throttling are two important concepts to understand when working with ARM templates. Concurrency refers to the number of resources that can be deployed at the same time, while throttling refers to the number of concurrent deployments that can happen in a given time period. Both concepts can help you control the rate at which resources are deployed, and can help prevent overloading the system.

18. What are the key differences between ARM templates and Azure Cloud Formation Templates? Which one do you prefer and why?

The main difference between ARM templates and Azure Cloud Formation templates is that ARM templates are designed to be used with Azure Resource Manager, while Azure Cloud Formation templates are designed to be used with Azure Service Management. I prefer ARM templates because they are more user-friendly and easier to work with in my opinion.

19. What are the main benefits of using ARM templates?

The main benefits of using ARM templates are that they allow for greater control and flexibility when deploying Azure resources, and they can also help to automate the process of resource deployment. Additionally, ARM templates can help to ensure that resources are deployed in a consistent and repeatable manner.

20. How many types of variables are available in ARM templates?

There are two types of variables available in ARM templates: variables and parameters. Variables are used to store values that are used throughout the template, while parameters are used to store values that can be passed in when the template is deployed.