A Route53 health check is used to monitor the health of web applications, CloudWatch alarms, or even other health checks. Health checks are necessary for configuring DNS failover in Route53.
Route53 health checks are typically already associated with automated actions such as DNS failover or SNS notifications. When Blue Matador detects that a Route53 health check was recently unhealthy, an anomaly is recorded so that it can be correlated with other issues in your system.
To diagnose the cause of the failing health check, look at the health check in the AWS Console. If the health check is calculated from the status of other health checks or CloudWatch alarms, investigate those. If the health check is configured against endpoints, you can use the Health checkers tab in the AWS console to view the status from each region as well as the last failure of the health check.
How Health Checks Work in Simple Amazon Route 53 Configurations (AWS Documentation)
How Amazon Route 53 Determines Whether a Health Check Is Healthy (AWS Documentation)