AWS Alerts to Slack Terraform Module

• AWS Alerts to Slack Terraform Module
  • Overview
  • Alerting Flow:
  • Features
  • Implemented Alerts
  • Configuration Guide
    • Setting Up AWS Chatbot in Slack
    • Configuring Slack Channel to SNS Topic

Overview

The aws-alerts-to-slack Terraform module offers a seamless method to monitor critical AWS alerts and relay them directly to your Slack workspace. By encapsulating the complexities of AWS services and configurations, this module delivers a straightforward deployment process, allowing quick integration of comprehensive monitoring and alerting into your infrastructure.

Alerting Flow:

1. AWS Service Alert: Utilizes native AWS alerts based on your preferences, from AWS cost anomaly detections to AWS Health events.

2. AWS SNS Topic: When an alert is activated, it's sent to a designated SNS topic. This centralizes alert messages, enabling delivery to multiple subscribers when required.

3. AWS Chatbot: AWS Chatbot processes these SNS messages, serving as a conduit between AWS and Slack, and transforms the SNS messages into a Slack-friendly format.

4. Slack: The alert is then dispatched to your specified Slack channel, ensuring prompt responses to potential issues or anomalies.

Features

• Easy Deployment: By simplifying AWS configurations, the module allows for a swift deployment of a potent alerting system.

• Standardized Alerts: Provides a uniform alerting mechanism across various AWS services.

• Modularity: Each AWS service alert is structured as an individual module, enhancing code maintainability and offering users the freedom to select alerts pertinent to their infrastructure.

Implemented Alerts

Currently, the module supports the following alerts:

• Savings Plans Utilization Alert: Notifies users when Savings Plans utilization falls below a specified threshold.

• Budget Alerts: Monitors forecasted and actual costs. Sends an alert if costs exceed a specific percentage of a set budget. By default, notifications are generated at 100%, 150%, and 200% of the budget for both forecasted and actual costs.

• GuardDuty Findings: Routes AWS GuardDuty findings directly to Slack.

• AWS Health Events: Keeps track of AWS Health-related events.

The following alerts are in the testing phase and should be used with caution:

• Reservations Utilization Alert: Triggers when Reserved Instance utilization falls below a specified threshold.

• Cost Anomaly Detection: Leverages AWS Cost Explorer's Cost Anomaly Detection for alerts.

For more information on each alert type, please refer to the /modules directory.

Configuration Guide

Before deploying this module, you must set up the Slack workspace. Follow the steps below or consult the official documentation.

Setting Up AWS Chatbot in Slack

1. In Slack's left navigation pane, select Apps.

   Note: If Apps isn't visible, click on More, then choose Apps.

2. If AWS Chatbot isn't listed, click on Browse Apps Directory.
3. Search for the AWS Chatbot app and click Add to integrate it into your workspace.
4. Navigate to the AWS Chatbot console.
5. Under "Configure a chat client", select Slack, then Configure client.
6. From the dropdown list, choose the Slack workspace you wish to use with AWS Chatbot.
7. Click Allow.

Configuring Slack Channel to SNS Topic

Configure the Slack channel to SNS topic mapping using /modules/slack-workspace.

module "chatbot_slack_workspace" {
  source = "./modules/slack_workspace"

  workspace_id = local.slack.workspace_id
  default_iam_role_arn = module.chatbot_role.iam_role_arn

  channels_config = {
    test = {
      slack_channel_id = local.slack.channel["dev-alerts"]
      sns_topic_arns   = prod_sns_topic_arn
    }
  }
  tags = module.tags.result
}

Afterward, create an SNS topic and link it to the Slack channel:

# SNS topic for Chatbot
resource "aws_sns_topic" "chatbot" {
  name = "test_chatbot_topic"
}

# SNS topic policy for Chatbot
resource "aws_sns_topic_policy" "chatbot_topic" {
  arn    = aws_sns_topic.chatbot.arn
  policy = jsonencode({
    // policy details
  })
}

Subsequently, you can leverage any alert module from the /modules directory or devise your custom alert, then subscribe it to the SNS topic. Here's an example of the budget alert:

# This automatically establishes a budget with notifications for 100%, 150%, and 200% of the limit amount for both forecasted and actual costs
module "budget_alerts" {
  source = "./modules/budget_alerts"

  limit_amount                = "10000"
  subscriber_sns_topic_arns   = local.prod_sns_topic_arn
  subscriber_email_addresses  = local.budget_subscriber_email_addresses
}

For additional usage examples, consult the /examples directory.

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