Terraform Module: terraform-module-aws-cloudwatch-metric-alarm

Terraform Module for AWS AWS CloudWatch Metric Alarm

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This is a stable example. It should successfully build out of the box

This examples does is built on Construct Libraries marked "Stable" and does not have any infrastructure prerequisites to build.

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General

This module may be used to create AWS CloudWatch Metric Alarm resources in AWS cloud provider......

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Prerequisites

This module needs Terraform 0.12.19 or newer. You can download the latest Terraform version from here.

This module deploys aws services details are in respective feature branches.

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Features

Below we are able to check the resources that are being created as part of this module call:

• AWS CloudWatch Metric Alarm

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Usage

Using this repo

To use this module, add the following call to your code:

• Example Usage

• Example in Conjunction with Scaling Policies

module "cloudwatch_metric_alarm_up" {
  source = "git::https://github.com/nitinda/terraform-module-aws-cloudwatch-metric-alarm.git?ref=master"

  providers = {
    aws = aws.services
  }

  alarm_name          = "AlarmHigh"
  comparison_operator = "GreaterThanOrEqualToThreshold"
  evaluation_periods  = "2"
  metric_name         = "CPUUtilization"
  namespace           = "AWS/EC2"
  period              = "120"
  statistic           = "Average"
  threshold           = "80"
  alarm_description   = "This metric monitors ec2 cpu utilization"
  
}

• Example with an Expression

module "cloudwatch_metric_alarm_up" {
  source = "git::https://github.com/nitinda/terraform-module-aws-cloudwatch-metric-alarm.git?ref=master"

  providers = {
    aws = aws.services
  }

  alarm_name          = "AlarmHigh"
  comparison_operator = "GreaterThanOrEqualToThreshold"
  evaluation_periods  = "2"
  metric_name         = "CPUUtilization"
  namespace           = "AWS/EC2"
  period              = 60
  statistic           = "Average"
  threshold           = 20
  datapoints_to_alarm = 1

  dimensions = {
    AutoScalingGroupName = module.autoscaling_group.name
  }

  alarm_description = "This metric monitors ec2 cpu utilization"
  alarm_actions     = [ module.aws_autoscaling_policy.arn ]
  
}

• Example of monitoring Healthy Hosts on NLB using Target Group and NLB

module "cloudwatch_metric_alarm_up" {
  source = "git::https://github.com/nitinda/terraform-module-aws-cloudwatch-metric-alarm.git?ref=master"

  providers = {
    aws = aws.services
  }

  alarm_name          = "AlarmHigh"
  comparison_operator = "GreaterThanOrEqualToThreshold"
  evaluation_periods  = "2"
  threshold           = "10"
  alarm_description   = "Request error rate has exceeded 10%"

  metric_query {
    id          = "e1"
    expression  = "m2/m1*100"
    label       = "Error Rate"
    return_data = "true"
  }

  metric_query {
    id = "m1"

    metric {
      metric_name = "RequestCount"
      namespace   = "AWS/ApplicationELB"
      period      = "120"
      stat        = "Sum"
      unit        = "Count"

      dimensions = {
        LoadBalancer = "app/web"
      }
    }
  }

  metric_query {
    id = "m2"

    metric {
      metric_name = "HTTPCode_ELB_5XX_Count"
      namespace   = "AWS/ApplicationELB"
      period      = "120"
      stat        = "Sum"
      unit        = "Count"

      dimensions = {
        LoadBalancer = "app/web"
      }
    }
  }
  
}

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Inputs

The variables required in order for the module to be successfully called from the deployment repository are the following:

NOTE: You cannot create a metric alarm consisting of both statistic and extended_statistic parameters. You must choose one or the other

Variable	Description	Type	Argument Status	Default Value
alarm_name	The descriptive name for the alarm. This name must be unique within the user's AWS account	string	Required
comparison_operator	The arithmetic operation to use when comparing the specified Statistic and Threshold. The specified Statistic value is used as the first operand. Either of the following is supported: GreaterThanOrEqualToThreshold, GreaterThanThreshold, LessThanThreshold, LessThanOrEqualToThreshold. Additionally, the valuesLessThanLowerOrGreaterThanUpperThreshold, LessThanLowerThreshold, and GreaterThanUpperThreshold are used only for alarms based on anomaly detection models.	string	Required
evaluation_periods	The number of periods over which data is compared to the specified threshold.	number	Required
metric_name	The name for the alarm's associated metric	string	Optional	null
namespace	The namespace for the alarm's associated metric	string	Optional	null
period	The period in seconds over which the specified statistic is applied	number	Optional	null
statistic	The statistic to apply to the alarm's associated metric. Either of the following is supported: SampleCount, Average, Sum, Minimum, Maximum	string	Optional	null
threshold	The value against which the specified statistic is compared. This parameter is required for alarms based on static thresholds, but should not be used for alarms based on anomaly detection models.	number	Optional	null
threshold_metric_id	If this is an alarm based on an anomaly detection model, make this value match the ID of the ANOMALY_DETECTION_BAND function	string	Optional	null
actions_enabled	Indicates whether or not actions should be executed during any changes to the alarm's state. Defaults to true	boolean	Optional	true
alarm_actions	The list of actions to execute when this alarm transitions into an ALARM state from any other state. Each action is specified as an Amazon Resource Name (ARN).	string	Optional	null
alarm_description	The description for the alarm	string	Optional	null
datapoints_to_alarm	The number of datapoints that must be breaching to trigger the alarm.	string	Optional	null
dimensions	The dimensions for the alarm's associated metric. For the list of available dimensions see the AWS documentation here.	string	Optional	null
alarm_description	The description for the alarm	string	Optional	null
insufficient_data_actions	The description for the alarm	list(string)	Optional	null
alarm_description	The list of actions to execute when this alarm transitions into an INSUFFICIENT_DATA state from any other state. Each action is specified as an Amazon Resource Name (ARN).	string	Optional	null
ok_actions	The list of actions to execute when this alarm transitions into an OK state from any other state. Each action is specified as an Amazon Resource Name (ARN).	list(string)	Optional	null
unit	The unit for the alarm's associated metric	string	Optional	null
extended_statistic	The percentile statistic for the metric associated with the alarm. Specify a value between p0.0 and p100.	string	Optional	null
treat_missing_data	Sets how this alarm is to handle missing data points. The following values are supported: missing, ignore, breaching and notBreaching. Defaults to missing	string	Optional	missing
evaluate_low_sample_count_percentiles	Used only for alarms based on percentiles. If you specify ignore, the alarm state will not change during periods with too few data points to be statistically significant. If you specify evaluate or omit this parameter, the alarm will always be evaluated and possibly change state no matter how many data points are available. The following values are supported: ignore, and evaluate	string	Optional	null
metric_query	Enables you to create an alarm based on a metric math expression. You may specify at most 20.	any	Optional	null
tags	A map of tags to assign to the resource.	any	Optional	{}

NOTE: If you specify at least one metric_query, you may not specify a metric_name, namespace, period or statistic. If you do not specify a metric_query, you must specify each of these (although you may use extended_statistic instead of statistic).

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Outputs

General

This module has the following outputs:

The ARN of the cloudwatch metric alarm

• arn

The ID of the health check

• id

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Usage

In order for the variables to be accessed on module level please use the syntax below:

module.<module_name>.<output_variable_name>

The output variable is able to be accessed through terraform state file using the syntax below:

data.terraform_remote_state.<module_name>.<output_variable_name>

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Authors

Module maintained by Module maintained by the - Nitin Das