Azure Monitor

Log Types

• https://docs.microsoft.com/en-us/azure/security/fundamentals/log-audit

Alert Types

Alert type	When to use	Pricing information
Metric alert	Metric data is stored in the system already pre-computed. Metric alerts are useful when you want to be alerted about data that requires little or no manipulation. Use metric alerts if the data you want to monitor is available in metric data.	Each metric alert rule is charged based on the number of time series that are monitored.
Log alert	You can use log alerts to perform advanced logic operations on your data. If the data you want to monitor is available in logs, or requires advanced logic, you can use the robust features of Kusto Query Language (KQL) for data manipulation by using log alerts.	Each log alert rule is billed based on the interval at which the log query is evaluated. More frequent query evaluation results in a higher cost. For log alerts configured for at-scale monitoring, the cost also depends on the number of time series created by the dimensions resulting from your query.
Activity log alert	Activity logs provide auditing of all actions that occurred on resources. Use activity log alerts to be alerted when a specific event happens to a resource like a restart, a shutdown, or the creation or deletion of a resource. Service Health alerts and Resource Health alerts let you know when there's an issue with one of your services or resources.	For more information, see the pricing page: https://azure.microsoft.com/en-us/pricing/details/monitor/
Prometheus alerts (preview)	Prometheus alerts are primarily used for alerting on performance and health of Kubernetes clusters, including Azure Kubernetes Service. The alert rules are based on PromQL, which is an open-source query language.	There's no charge for Prometheus alerts during the preview period.

• Reference: https://learn.microsoft.com/en-us/azure/azure-monitor/alerts/alerts-types#choose-the-right-alert-type