diff --git a/CHANGELOG.md b/CHANGELOG.md
index 66b1f3a..ed27423 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,10 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+- refs #000: add link for CloudWatch Observability EKS addon.
+
 ## [1.0.0] - 2023-11-22
 
 [Compare with previous version](https://github.com/sparkfabrik/terraform-aws-eks-bootstrap/compare/0.3.0...1.0.0)
diff --git a/variables.tf b/variables.tf
index 35fe97a..f0efe4f 100644
--- a/variables.tf
+++ b/variables.tf
@@ -71,6 +71,7 @@ variable "cloudwatch_log_group_retention_in_days" {
   default     = 7
 }
 
+# https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/install-CloudWatch-Observability-EKS-addon.html
 variable "cluster_enable_amazon_cloudwatch_observability_addon" {
   type        = bool
   description = "Indicates whether to enable the Amazon CloudWatch Container Insights for Kubernetes."