Resource Tags
😟 THE PROBLEM
Finance asks what Marketing spent, and nobody can tell.
😊 THE SOLUTION
Tag resources with owner, department and environment.
- Costs can’t be split by team✓ Group cost analysis by tag
- Unknown resource owners✓ owner tag on everything
- Manual shutdowns✓ Automate by env=dev tag
Quick answer
Resource tags are name-value pairs (such as env = production or costCenter = 1234) that you attach to Azure resources, resource groups and subscriptions. They add metadata that helps with cost reporting, resource management, operations and automation, security and governance and compliance. Tags are not inherited by default.
Exam objective: 3.1.4 Describe the purpose of tags. (Skills measured as of July 20, 2026)
Start with a question
Finance asks how much the Marketing department spent on Azure last month. How do you answer in one minute?
If every resource is tagged department = marketing, filter cost analysis by that tag. Done.
Explain it like I’m 10
The technical explanation
Each resource can have many tags. Typical tags:
| Name | Example value | Used for |
|---|---|---|
| env | production, dev | Automation, policy |
| owner | sam@contoso.com | Accountability |
| costCenter | 1234 | Cost reporting |
| dataClass | confidential | Security |
Real-world business scenario
A university IT department
- The problem
- Nobody knew which faculty owned hundreds of resources.
- What they used
- Required tags (owner, faculty, env) enforced with Azure Policy, and cost analysis grouped by faculty.
- Why that choice
- Tags give every resource an owner and a cost centre.
- The result
- Monthly cost reports per faculty, and orphaned resources easily traced.
When to use it and when not to
✓ Use it when…
- Tag everything with owner, cost centre and environment.
✕ Think twice when…
- Storing secrets or personal data in tags.
Interview preparation
Say your answer out loud first, then open the model answer. Interviewers care more about your reasoning than the exact words.
Beginner What are tags in Azure?
Model answer
Labels made of a name and value, like department equals finance, that I put on resources to organise them and report costs.
Intermediate What are common uses of tags?
Model answer
Cost allocation by department or project, identifying owners and environments, automation such as shutting down resources tagged env=dev at night, marking data sensitivity for security, and governance reporting.
Experienced developer How do you make tagging consistent across a company?
Model answer
Define a small required set (owner, costCenter, env), enforce it with Azure Policy (deny or modify effects, and inherit tags from resource groups), set it in infrastructure as code templates, and report non-compliance.
Test yourself with exercises
3 original practice questions in the AZ-900 style. Pick your answers, then check them. You will see why each option is right or wrong. Score 75% or more and this topic is marked complete.
Quick revision
Key points
- Tags = name-value metadata on resources.
- Used for cost reporting, ownership, automation, security and governance.
- Not inherited by default; Azure Policy can enforce and inherit.
Important terminology
- Tag
- A name-value pair of metadata on a resource.
- Tag inheritance
- Resources do not inherit tags from their group by default; Azure Policy can enforce or copy them.
Common mistakes
- Assuming tags on a resource group automatically appear on its resources.
Exam tips
- "Group costs by department across resource groups" = tags.
Five quick revision questions
-
1.What is a tag made of?Show
A name and a value.
-
2.Are tags inherited by default?Show
No.
-
3.How can you enforce tags?Show
With Azure Policy.
-
4.Give two uses of tags.Show
Cost reporting and identifying owners (also automation and governance).
-
5.Can you tag resource groups and subscriptions?Show
Yes.
Official references
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Next up: Microsoft Purview