AWS Cost Anomaly Detection Alert Terraform Module

💰 Terraform module for AWS Cost Anomaly Detection with optional Slack integration to monitor and alert on unexpected AWS cost increases 📊

Features

• Creates AWS Cost Anomaly Monitor for service-level monitoring
• Configures Anomaly Subscription with flexible threshold conditions
• Sets up SNS topic and required policies for notifications
• Optional Slack integration via AWS Chatbot
• Consistent resource naming and tagging

Note

You will need to configure AWS Chatbot client using the AWS Console before you use slack integration of this module.

AWS Chatbot Client Slack Integration Screenshot

Usage(Example)

Basic Usage with AND Conditions

module "cost_anomaly_alert" {
  source = "keidarcy/cost-anomaly-detection-alert/aws"

  name = "sre-cost-anomaly"

  threshold_expressions = [
    {
      operator = "and"
      conditions = [
        {
          key           = "ANOMALY_TOTAL_IMPACT_PERCENTAGE"
          values        = ["10"]
          match_options = ["GREATER_THAN_OR_EQUAL"]
        },
        {
          key           = "ANOMALY_TOTAL_IMPACT_ABSOLUTE"
          values        = ["100"]
          match_options = ["GREATER_THAN_OR_EQUAL"]
        }
      ]
    }
  ]

  tags = {
    Environment = "Production"
  }
}

With SNS Integration

module "cost_anomaly_alert" {
  source = "keidarcy/cost-anomaly-detection-alert/aws"

  name = "sre-cost-anomaly"

  threshold_expressions = [
    {
      operator = "or"
      conditions = [
        {
          key           = "ANOMALY_TOTAL_IMPACT_PERCENTAGE"
          values        = ["10"]
          match_options = ["GREATER_THAN_OR_EQUAL"]
        },
        {
          key           = "ANOMALY_TOTAL_IMPACT_ABSOLUTE"
          values        = ["100"]
          match_options = ["GREATER_THAN_OR_EQUAL"]
        }
      ]
    }
  ]

  # Enable Slack integration
  enable_slack_integration = true
  slack_workspace_id       = "TXXXXXXXX"
  slack_channel_id        = "CXXXXXXXX"

  # Enable Email subscription
  enable_email_integration = true
  email_recipients         = ["[email protected]", "[email protected]"]

  tags = {
    Environment = "Production"
  }
}

Requirements

Name	Version
terraform	>= 0.13.0
aws	>= 4.0.0

Providers

Name	Version
aws	>= 4.0.0

Resources Created

This module creates the following resources:

• AWS Cost Explorer Anomaly Monitor
• AWS Cost Explorer Anomaly Subscription
• SNS Topic with required policies
• AWS Chatbot configuration (optional)
• IAM roles and policies for AWS Chatbot (when Slack integration is enabled)
• EMAIL subscription for SNS (when email address is provided)

Inputs

Name	Description	Type	Default	Required
name	Base name for all resources	string	"cost-anomaly"	yes
threshold_expressions	List of threshold expressions	list(object)	See variables.tf	yes
enable_slack_integration	Enable Slack integration	bool	false	no
slack_workspace_id	Slack Workspace ID	string	""	no
slack_channel_id	Slack Channel ID	string	""	no
enable_email_integration	Enable Email integration	bool	false	no
email_recipients	Email recipients for SNS	list(string)	[]	no
tags	Resource tags	map(string)	{}	no

Outputs

Name	Description
monitor_id	ID of the Cost Anomaly Monitor
subscription_id	ID of the Cost Anomaly Subscription
sns_topic_arn	ARN of the SNS topic
chatbot_role_arn	ARN of the Chatbot IAM role

Resource Naming

The module creates resources with the following naming pattern:

• Monitor: {name}-monitor
• Subscription: {name}-subscription
• SNS Topic: {name}-topic
• Chatbot Role: {name}-chatbot-role
• Chatbot Policy: {name}-chatbot-policy
• Chatbot Stack: {name}-chatbot

Tags

All resources are tagged with:

• Default tags:
  • ManagedBy: "terraform"
  • Module: "cost-anomaly-alert"
• User-provided tags (merged with defaults)

Notes

1. The module supports either AND or OR conditions, but not both simultaneously
2. Each expression can have up to 2 conditions
3. Slack integration requires valid Workspace and Channel IDs
4. All resource names must follow AWS naming restrictions

Authors

Module is maintained by Xing Yahao(https://github.com/keidarcy)

License