If you run applications or workloads on Microsoft Azure, you need a way to know when something goes wrong or when performance isn’t what it should be. That’s where Azure Monitor alerts come in. They notify you when specific conditions are met so you can take action before small issues turn into big problems.
What is an alert?
An alert is a rule you define in Azure Monitor. It watches signals from your resources (like metrics, logs, or activity events) and notifies you when something unusual happens.
For example:
- If a VM is deleted, you can get an email notification.
- If CPU usage is over 90%, you can trigger an SMS to your support team.
- If a Key Vault secret is about to expire, you can automatically run an Azure Function to rotate it.
Types of alert signals
Azure Monitor supports several types of signals. These are the “things” you can monitor:
- Metric alerts – Watch performance data like CPU, memory, or request rate.
- Log search alerts – Run queries across logs to detect patterns or errors.
- Simple log search alerts (preview) – A faster, lightweight option for basic log queries.
- Activity log alerts – Detect control-plane changes, such as creating, updating, or deleting resources.
- Service Health and Resource Health alerts – Notify you about Azure-wide outages or issues with your specific resource.
- Smart detection alerts (Application Insights) – Use AI to spot anomalies in your app’s performance.
- Prometheus alerts – For Kubernetes and containerized environments.
What happens when an alert fires?
When a condition is met, the alert triggers an Action Group. Action Groups define what happens next, such as:
- Sending an email or SMS.
- Calling a webhook.
- Running an Azure Function or Logic App.
- Opening a ticket in ITSM tools like ServiceNow.
Extra features to make alerts smarter
Azure Monitor also has features that make alerting more flexible:
- Alert Processing Rules – Suppress or redirect alerts during planned maintenance.
- Quick Actions – Send lightweight notifications without a full Action Group.
- Dynamic Thresholds – Let Azure learn normal patterns and detect anomalies automatically.
- Multi-resource alerts – Use one alert rule to monitor multiple resources.
- Stateless vs. Stateful – Control whether alerts fire repeatedly or only on state changes.
- Dimension filters – Target specific instances, regions, or APIs.
Why alerts matter
Azure Monitor alerts aren’t just about avoiding downtime — they help you:
- Keep systems reliable by acting fast.
- Maintain security by tracking unexpected changes.
- Improve efficiency by automating responses.
✅ In short: Azure Monitor alerts give you the eyes and ears you need in the cloud. Set them up wisely, and you’ll spend less time firefighting and more time building.