Global AWS Resources

Overview

The global AWS resources module provisions foundational infrastructure components that are shared across all environments (if multiple enviornments in one account) (development, staging, production). These resources are created once per account and referenced by environment-specific modules, ensuring consistency, security, and centralized management.

Why Global Resources?

Global resources provide:

Centralized Security: Single KMS key and IAM roles for encryption and access control
Audit Compliance: Unified CloudTrail logging for all API activity
Resource Reusability: IAM roles and policies shared across multiple modules
Consistency: Standardized configuration across all environments
Simplified Management: Update policies and permissions in one place

Core Components

1. KMS Encryption Key

A customer-managed KMS key that encrypts data at rest for all Artos resources, including EKS secrets, RDS databases, S3 buckets, CloudTrail logs, and Secrets Manager entries.

Key Features

Feature	Configuration	Purpose
Automatic Key Rotation	Enabled (annual)	Rotates encryption keys automatically for enhanced security
Deletion Protection	7-day window	Prevents accidental deletion with a recovery period
Multi-Service Access	EKS, RDS, S3, CloudTrail, Secrets Manager	Single key for all encryption needs
Key Alias	`alias/{project}-{environment}-kms-key`	Human-readable identifier for the key

Service Permissions

The KMS key policy grants encryption/decryption permissions to multiple AWS services:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "Enable IAM User Permissions",
      "Effect": "Allow",
      "Principal": {
        "AWS": "arn:aws:iam::ACCOUNT_ID:root"
      },
      "Action": "kms:*",
      "Resource": "*"
    },
    {
      "Sid": "Allow EKS Service",
      "Effect": "Allow",
      "Principal": {
        "Service": "eks.amazonaws.com"
      },
      "Action": [
        "kms:Encrypt",
        "kms:Decrypt",
        "kms:ReEncrypt*",
        "kms:GenerateDataKey*",
        "kms:DescribeKey"
      ],
      "Resource": "*"
    },
    {
      "Sid": "Allow RDS Service",
      "Effect": "Allow",
      "Principal": {
        "Service": "rds.amazonaws.com"
      },
      "Action": [
        "kms:Encrypt",
        "kms:Decrypt",
        "kms:ReEncrypt*",
        "kms:GenerateDataKey*",
        "kms:DescribeKey"
      ],
      "Resource": "*"
    }
    // Additional statements for S3, CloudTrail, Secrets Manager
  ]
}

What This Means: The KMS key can be used by AWS services on your behalf to encrypt/decrypt data without requiring manual intervention. The root account retains full administrative access to manage the key.

2. IAM Roles for EKS

The module creates three primary IAM roles for different EKS compute types, each with specific permissions for their function.

EKS Cluster Service Role

Purpose: Allows the EKS control plane to manage AWS resources on your behalf.

Property	Value
Role Name	`{project}-{environment}-eks-service-role`
Trust Policy	`eks.amazonaws.com`
Managed Policy	`AmazonEKSClusterPolicy`

What It Does:

Creates and manages Elastic Network Interfaces (ENIs) in your VPC
Manages security groups for cluster-VPC communication
Creates CloudWatch log streams for cluster logging
Describes EC2 resources to validate cluster configuration

EKS Node Group Role

Purpose: Grants EC2 worker nodes permissions to join the cluster, pull container images, and access AWS services.

Property	Value
Role Name	`{project}-{environment}-eks-node-group-role`
Trust Policy	`ec2.amazonaws.com`
Managed Policies	`AmazonEKSWorkerNodePolicy`, `AmazonEKS_CNI_Policy`, `AmazonEC2ContainerRegistryReadOnly`, `AmazonSSMManagedInstanceCore`

Additional Permissions:

Cross-Account ECR Access: Pull container images from the Artos-managed ECR registry
SSM Session Manager: Secure shell access to nodes without SSH keys

Cross-Account ECR Policy:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "ecr:GetAuthorizationToken"
      ],
      "Resource": "*"
    },
    {
      "Effect": "Allow",
      "Action": [
        "ecr:BatchCheckLayerAvailability",
        "ecr:GetDownloadUrlForLayer",
        "ecr:BatchGetImage",
        "ecr:DescribeRepositories",
        "ecr:DescribeImages"
      ],
      "Resource": [
        "arn:aws:ecr:*:<artos_ecr_aws_account>:repository/development/*",
        "arn:aws:ecr:*:<artos_ecr_aws_account>:repository/thirdparty/*"
      ]
    }
  ]
}

Why This Matters: Nodes can pull pre-built Artos container images from the centralized ECR registry without requiring image copies or manual transfers.

EKS Fargate Role

Purpose: Allows Fargate profiles to execute pods and pull container images.

Property	Value
Role Name	`{project}-{environment}-eks-fargate-role`
Trust Policy	`eks-fargate-pods.amazonaws.com`
Managed Policy	`AmazonEKSFargatePodExecutionRolePolicy`

Additional Permissions:

Cross-Account ECR Access: Same as node group role for image pulling

Fargate vs. Node Groups: Fargate pods run on AWS-managed infrastructure (serverless), while node groups run on customer-managed EC2 instances. The Fargate role is only used when Fargate profiles are configured.

RDS Enhanced Monitoring Role

Purpose: Allows RDS to publish detailed monitoring metrics to CloudWatch.

Property	Value
Role Name	`{project}-{environment}-rds-enhanced-monitoring-role`
Trust Policy	`monitoring.rds.amazonaws.com`
Managed Policy	`AmazonRDSEnhancedMonitoringRole`

What It Does: Enables RDS instances to send OS-level metrics (CPU, memory, disk I/O, network) to CloudWatch at 1-60 second intervals for detailed performance analysis.

3. CloudTrail Audit Logging

AWS CloudTrail records all API calls made in your AWS account, providing a complete audit trail for security analysis, compliance, and troubleshooting.

CloudTrail Configuration

Setting	Value	Purpose
Multi-Region Trail	Enabled	Captures API calls from all AWS regions
Global Service Events	Enabled	Logs IAM, STS, CloudFront events
Event Selector	All management events + S3 data events	Records resource creation/modification
Encryption	KMS (using global KMS key)	Encrypts log files at rest
Log Storage	S3 bucket with versioning	Immutable audit log

What CloudTrail Captures

Management Events (who did what):

EKS cluster creation/modification
RDS database parameter changes
IAM role assumption
Security group rule changes
S3 bucket policy updates

Data Events (data access):

S3 object uploads/downloads to CloudTrail bucket
API calls to Artos services

CloudTrail S3 Bucket

The module creates a dedicated S3 bucket for storing CloudTrail logs:

Feature	Configuration
Bucket Name	`{project}-{environment}-cloudtrail-logs-{random}`
Versioning	Enabled
Encryption	KMS (using global KMS key)
Force Destroy	Disabled (logs are retained even if Terraform is destroyed)
Bucket Policy	Allows CloudTrail service to write logs

Bucket Policy Example:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "AWSCloudTrailAclCheck",
      "Effect": "Allow",
      "Principal": {
        "Service": "cloudtrail.amazonaws.com"
      },
      "Action": "s3:GetBucketAcl",
      "Resource": "arn:aws:s3:::bucket-name"
    },
    {
      "Sid": "AWSCloudTrailWrite",
      "Effect": "Allow",
      "Principal": {
        "Service": "cloudtrail.amazonaws.com"
      },
      "Action": "s3:PutObject",
      "Resource": "arn:aws:s3:::bucket-name/*",
      "Condition": {
        "StringEquals": {
          "s3:x-amz-acl": "bucket-owner-full-control"
        }
      }
    }
  ]
}

Why This Policy: The AWSCloudTrailAclCheck statement allows CloudTrail to verify bucket permissions, while AWSCloudTrailWrite permits log file uploads with the bucket-owner-full-control ACL to ensure you maintain ownership of log files.

Module Configuration

Basic Configuration

# terraform.tfvars
project_name            = "genai-artos"
environment             = "production"
aws_region              = "us-east-1"
terraform_state_bucket  = "artos-terraform-state"

tags = {
  system_owner = "[email protected]"
  system_admin = "[email protected]"
  created_by   = "Terraform"
  cost_center  = "engineering"
  application  = "artos-backend"
}

Backend Configuration

The module uses S3 backend for Terraform state storage. Create a backend configuration file for each environment: File: backend-global-production-us-east-1.hcl

# Backend configuration for production environment in us-east-1
# Usage: terraform init -backend-config=backend-global-production-us-east-1.hcl

bucket = "artos-terraform-state"
key    = "global/production/us-east-1/terraform.tfstate"
region = "us-east-1"

Initialization and Deployment

# Initialize Terraform with backend configuration
terraform init -backend-config=backend-global-production-us-east-1.hcl

# Review planned changes
terraform plan

# Apply global resources
terraform apply

# View outputs (KMS key ARN, IAM role ARNs, CloudTrail ARN)
terraform output

Using Global Resources in Environment Modules

Global resources are referenced by environment-specific modules (networking, EKS, RDS, S3) using Terraform data sources or outputs from remote state.

Example: Referencing KMS Key in RDS Module

# Environment module references global KMS key
data "terraform_remote_state" "global" {
  backend = "s3"
  config = {
    bucket = "artos-terraform-state"
    key    = "global/production/us-east-1/terraform.tfstate"
    region = "us-east-1"
  }
}

# Use KMS key in RDS cluster
resource "aws_rds_cluster" "main" {
  cluster_identifier      = "artos-production"
  engine                  = "aurora-postgresql"
  storage_encrypted       = true
  kms_key_id             = data.terraform_remote_state.global.outputs.kms_key_arn
  # ... other configuration
}

Example: Referencing IAM Roles in EKS Module

# Reference global IAM roles
resource "aws_eks_cluster" "main" {
  name     = "artos-production"
  role_arn = data.terraform_remote_state.global.outputs.eks_service_role_arn
  # ... other configuration
}

resource "aws_eks_node_group" "main" {
  cluster_name    = aws_eks_cluster.main.name
  node_role_arn   = data.terraform_remote_state.global.outputs.eks_node_group_role_arn
  # ... other configuration
}

resource "aws_eks_fargate_profile" "main" {
  cluster_name           = aws_eks_cluster.main.name
  fargate_profile_name   = "artos-fargate"
  pod_execution_role_arn = data.terraform_remote_state.global.outputs.eks_fargate_role_arn
  # ... other configuration
}

Module Outputs

The global resources module exports the following outputs for use by other modules:

Output Name	Description	Example Value
`kms_key_id`	KMS key ID	`12345678-1234-1234-1234-123456789012`
`kms_key_arn`	KMS key ARN	`arn:aws:kms:us-east-1:123456789012:key/12345678-...`
`eks_service_role_arn`	EKS cluster service role ARN	`arn:aws:iam::123456789012:role/artos-prod-eks-service-role`
`eks_node_group_role_arn`	EKS node group role ARN	`arn:aws:iam::123456789012:role/artos-prod-eks-node-group-role`
`eks_fargate_role_arn`	EKS Fargate role ARN	`arn:aws:iam::123456789012:role/artos-prod-eks-fargate-role`
`rds_enhanced_monitoring_role_arn`	RDS monitoring role ARN	`arn:aws:iam::123456789012:role/artos-prod-rds-enhanced-monitoring-role`
`cloudtrail_arn`	CloudTrail ARN	`arn:aws:cloudtrail:us-east-1:123456789012:trail/artos-prod-cloudtrail`

Security Best Practices

1. KMS Key Management

Key Rotation:

Automatic key rotation is enabled by default (annual rotation)
Rotation is transparent to applications (AWS handles re-encryption)
Historical key material is retained for decrypting old data

Access Control:

Only the root account has full administrative access
Service principals have minimal required permissions (encrypt/decrypt only)
Consider creating separate KMS keys for highly sensitive data

2. IAM Role Security

Principle of Least Privilege:

Each role has only the permissions required for its specific function
Cross-account ECR access is limited to specific repositories
SSM Session Manager replaces SSH for secure node access

Trust Policies:

Trust policies restrict role assumption to specific AWS services
No direct user access to service roles (principle of least privilege)

Monitoring:

All role assumptions are logged in CloudTrail
Set up CloudWatch alarms for unexpected role usage

3. CloudTrail Audit Logging

Log Integrity:

Versioning enabled on log bucket prevents accidental deletion
KMS encryption protects log confidentiality
S3 Object Lock (optional) provides immutable audit logs

Access Control:

CloudTrail bucket policy restricts write access to CloudTrail service only
Separate IAM policy required to read logs (not granted by default)
Consider enabling S3 Access Logging for the CloudTrail bucket

Alerting:

# Example: CloudWatch alarm for CloudTrail logging disabled
resource "aws_cloudwatch_metric_alarm" "cloudtrail_disabled" {
  alarm_name          = "cloudtrail-logging-disabled"
  comparison_operator = "LessThanThreshold"
  evaluation_periods  = "1"
  metric_name         = "IsLogging"
  namespace           = "CloudTrailMetrics"
  period              = "300"
  statistic           = "Average"
  threshold           = "1"
  alarm_description   = "CloudTrail logging has been disabled"
  alarm_actions       = [aws_sns_topic.alerts.arn]
}

Operational Considerations

Cross-Account ECR Access

The global IAM roles include policies for pulling images from the Artos-managed ECR registry. This enables: Centralized Image Management:

Artos team maintains pre-built, tested container images
Automatic security patching and updates
Version-controlled image releases

Required Configuration:

On Artos Side: ECR repository policies must allow your AWS account to pull images
On Customer Side: IAM roles (created by this module) grant nodes permission to pull images. These updates can also be added to each ECR repository.

Terraform State Management

Backend Configuration:

Global resources use S3 backend for state storage
State file contains sensitive data (ARNs, resource IDs)
Enable S3 versioning and encryption on state bucket
The environment specific state files will be different for than the global tfstate files for each environment.

State Locking:

# Add DynamoDB table for state locking
terraform {
  backend "s3" {
    bucket         = "artos-terraform-state"
    key            = "global/production/us-east-1/global.tfstate"
    region         = "us-east-1"
    dynamodb_table = "terraform-state-lock"
    encrypt        = true
  }
}

Resource Dependencies

Deployment Order:

First: Deploy global resources module
Second: Deploy networking module (VPC, subnets, security groups)
Third: Deploy environment-specific modules (EKS, RDS, S3, etc.)

Why This Order: Environment modules reference global resource outputs (KMS key ARN, IAM role ARNs) via remote state, so global resources must exist first.

Troubleshooting

Issue: KMS Key Access Denied

Symptom: Services (EKS, RDS) cannot encrypt/decrypt data using KMS key. Solution:

# Verify KMS key policy includes service principal
aws kms get-key-policy --key-id <KEY_ID> --policy-name default

# Check CloudTrail for denied KMS API calls
aws cloudtrail lookup-events \
  --lookup-attributes AttributeKey=EventName,AttributeValue=Decrypt \
  --max-results 10

Issue: Cross-Account ECR Pull Failures

Symptom: EKS pods cannot pull images from Artos ECR registry. Solution:

# Verify IAM role policy is attached to node group role
aws iam list-attached-role-policies --role-name <NODE_GROUP_ROLE_NAME>
aws iam get-role-policy --role-name <NODE_GROUP_ROLE_NAME> --policy-name cross-account-ecr

# Test ECR authentication from node
kubectl run test-pod --image=<artos_ecr_aws_account>.dkr.ecr.us-east-1.amazonaws.com/development/test:latest
kubectl describe pod test-pod  # Check for ImagePullBackOff errors

Common Causes:

ECR repository policy does not allow your AWS account
IAM role policy has incorrect repository ARNs
Node instance profile not associated with IAM role

The global resources module is referenced by:

Networking Module: Uses KMS key for VPC Flow Logs encryption
EKS Module: Uses IAM roles for cluster, nodes, and Fargate
RDS Module: Uses KMS key for database encryption and enhanced monitoring role
S3 Module: Uses KMS key for bucket encryption
IAM Module: References service roles for IRSA configuration

API Documentation

Concepts

SDK Reference

Integrations

Deployment

Overview

Why Global Resources?

Core Components

1. KMS Encryption Key

Key Features

Service Permissions

2. IAM Roles for EKS

EKS Cluster Service Role

EKS Node Group Role

EKS Fargate Role

RDS Enhanced Monitoring Role

3. CloudTrail Audit Logging

CloudTrail Configuration

What CloudTrail Captures

CloudTrail S3 Bucket

Module Configuration

Basic Configuration

Backend Configuration

Initialization and Deployment

Using Global Resources in Environment Modules

Example: Referencing KMS Key in RDS Module

Example: Referencing IAM Roles in EKS Module

Module Outputs

Security Best Practices

1. KMS Key Management

2. IAM Role Security

3. CloudTrail Audit Logging

Operational Considerations

Cross-Account ECR Access

Terraform State Management

Resource Dependencies

Troubleshooting

Issue: KMS Key Access Denied

Issue: Cross-Account ECR Pull Failures

API Documentation

Concepts

SDK Reference

Integrations

Deployment

​Overview

​Why Global Resources?

​Core Components

​1. KMS Encryption Key

​Key Features

​Service Permissions

​2. IAM Roles for EKS

​EKS Cluster Service Role

​EKS Node Group Role

​EKS Fargate Role

​RDS Enhanced Monitoring Role

​3. CloudTrail Audit Logging

​CloudTrail Configuration

​What CloudTrail Captures

​CloudTrail S3 Bucket

​Module Configuration

​Basic Configuration

​Backend Configuration

​Initialization and Deployment

​Using Global Resources in Environment Modules

​Example: Referencing KMS Key in RDS Module

​Example: Referencing IAM Roles in EKS Module

​Module Outputs

​Security Best Practices

​1. KMS Key Management

​2. IAM Role Security

​3. CloudTrail Audit Logging

​Operational Considerations

​Cross-Account ECR Access

​Terraform State Management

​Resource Dependencies

​Troubleshooting

​Issue: KMS Key Access Denied

​Issue: Cross-Account ECR Pull Failures

​Related Modules

Overview

Why Global Resources?

Core Components

1. KMS Encryption Key

Key Features

Service Permissions

2. IAM Roles for EKS

EKS Cluster Service Role

EKS Node Group Role

EKS Fargate Role

RDS Enhanced Monitoring Role

3. CloudTrail Audit Logging

CloudTrail Configuration

What CloudTrail Captures

CloudTrail S3 Bucket

Module Configuration

Basic Configuration

Backend Configuration

Initialization and Deployment

Using Global Resources in Environment Modules

Example: Referencing KMS Key in RDS Module

Example: Referencing IAM Roles in EKS Module

Module Outputs

Security Best Practices

1. KMS Key Management

2. IAM Role Security

3. CloudTrail Audit Logging

Operational Considerations

Cross-Account ECR Access

Terraform State Management

Resource Dependencies

Troubleshooting

Issue: KMS Key Access Denied

Issue: Cross-Account ECR Pull Failures

Related Modules