Inhibit rules

A Prometheus inhibit rule is a configuration in Alertmanager that prevents certain alerts from firing when other higher-priority or related alerts are already active. It's a way to reduce alert noise by suppressing redundant or less important notifications.

Structure

In an inhibit rule we must define:

• Source alerts

They are alerts that will supress other alerts when active.

• Target alerts:

They are the alerts that will be suppressed when source alerts match

Example cases

• Supress alerts related with diskspace, cpu usage or memory usage when the node is down
• Supress warning alerts when critical alerts are firing about the same topic
• Supress a less important alert when a more important alert. For example, don't alert an application is down when its loadbalancer is down, that causes the application is down

In prometheus operator this can be achieved using an AlertmanagerConfig kubernetes resource spec.inhibitRules