Individual health monitors have a set of health policies that trigger alerts when certain conditions or state changes occur. Understanding how health monitoring works can help you respond to problems and control future alerts.
Health monitoring consists of the following components:
For example, the Storage subsystem has a node connectivity health monitor.
A degraded status in any single subsystem results in a degraded status for the entire system. If no subsystems have alerts, the overall system status is OK.
Each health monitor is made up of the following key elements:
Each alert has a definition, which includes details such as the severity of the alert and its probable cause.
Each health policy has a rule expression, which is the exact condition or change that triggers the alert.
A health monitor continuously monitors and validates the resources in its subsystem for condition or state changes. When a condition or state change matches a rule expression in a health policy, the health monitor raises an alert. An alert causes the subsystem's health status and the overall system health status to become degraded.