20-03 CloudWatch Alarms

Last updated Aug 17, 2023 Edit Source

A CloudWatch Alarm monitors a CloudWatch Metric based on a defined threshold.

When alarm breaches (goes outside the defined threshold) then it changes state.

Metric Alarm States

• OK The metric or expression is within the defined threshold

• ALARM The metric or expression is outside of the defined threshold

• INSUFFICIENT_DATA

  • The alarm has just started
  • the metric is not available
  • Not enough data is available

When it changes state we can define what action it should trigger.

• Notification
• Auto Scaling Group
• EC2 Action