cloudwatch-alb-error-rate.tf

resource "aws_cloudwatch_metric_alarm" "alb_error_rate" {
  alarm_name          = "${aws_lb.main.name}-alb-error-rate"
  comparison_operator = "GreaterThanOrEqualToThreshold"
  evaluation_periods  = 2
  threshold           = 5
  alarm_description   = "Load balancer error rate has exceeded 5%"
  treat_missing_data  = "notBreaching"

  metric_query {
    id          = "error_rate"
    expression  = "5xx_count / request_count *100"
    label       = "Error Rate"
    return_data = true
  }

  # metric queries for 5xx_count and request_count...
}