Alert rules (metric, log search, activity log), action groups and alert processing rules

Alerts in Azure Monitor tell you when something needs attention and can start automatic responses. An alert rule has three parts: the scope (which resources it watches), the condition (what triggers it) and the actions (what happens when it fires, through action groups). Each rule also has a severity from 0 (critical) to 4 (verbose) and a name and description that appear in notifications. Choosing the right rule type for a scenario is one of the most tested monitoring skills.