AWS Scheduler

Automates the start/stop lifecycle of EC2 and RDS resources using AWS Lambda and EventBridge. Terraform provisions the required infrastructure while Python Lambda functions perform the actions through Boto3.

Repository Structure

.
├── lambda_layer.tf        # Lambda Layer configuration and local build setup
├── ec2_scheduler.tf       # EC2 scheduler module instantiation
├── rds_scheduler.tf       # RDS scheduler module instantiation
├── codebuild.tf           # S3 bucket configuration for artifacts
├── build_layer.sh         # Local build script for Lambda Layer
├── requirements.txt       # Python dependencies for the Lambda Layer
└── modules/               # Reusable Terraform modules
    ├── ec2_scheduler/     # EC2 automation
    └── rds_scheduler/     # RDS automation

Key Features

1. Automated Scheduling

   • Start/stop EC2 instances based on tags
   • Start/stop RDS instances based on tags
   • Configurable schedule using cron expressions

2. Infrastructure as Code

   • Terraform for provisioning and management
   • Modular design for easy maintenance
   • Local build process for Lambda Layer

3. Monitoring & Logging

   • CloudWatch Logs for all Lambda executions
   • Detailed logging for troubleshooting

Prerequisites

• Terraform >= 1.3
• AWS CLI configured with appropriate permissions
• Python 3.9+ for local development
• AWS credentials configured with sufficient permissions

Local Development Setup

1. Clone the repository

   git clone https://github.com/your-repo/aws-scheduler.git
   cd aws-scheduler

2. Install Python dependencies

   pip install -r requirements.txt

3. Make the build script executable

   chmod +x build_layer.sh

Building the Lambda Layer Locally

The Lambda Layer is built locally using the build_layer.sh script. This script:

1. Creates a temporary directory for the layer
2. Installs dependencies from requirements.txt
3. Creates a ZIP archive of the dependencies

To manually build the layer:

./build_layer.sh

Deploying with Terraform

1. Initialize Terraform

   terraform init

2. Review the execution plan

   terraform plan

3. Apply the configuration

   terraform apply

   Terraform will automatically build the Lambda Layer and deploy all resources.

Configuration

Environment Variables

Variable	Description	Default
AWS_REGION	AWS region to deploy resources	eu-west-1
github_repo_url	GitHub repository URL	https://github.com/your-repo/aws-scheduler.git

Scheduler Configuration

• EC2 Instances: Tag your instances with stopstart = enabled
• RDS Instances: Tag your instances with stopstart = enabled

Default schedule (configurable in Terraform variables):

• Start: 13:00 local time
• Stop: 18:00 local time

Monitoring

• CloudWatch Logs:
  • /aws/lambda/dev-ec2-scheduler-to-start
  • /aws/lambda/dev-ec2-scheduler-to-stop
  • /aws/lambda/dev-rds-scheduler-to-start
  • /aws/lambda/dev-rds-scheduler-to-stop

Cleanup

To remove all resources:

terraform destroy

Remote State

State is stored in an S3 bucket with a DynamoDB table for locking. Update the backend configuration in versions.tf with your bucket and table names before running terraform init.

Suggestions for further study

• Terraform – explore modules, variables and outputs to customize deployments.
• AWS EventBridge & Lambda – learn how cron expressions work in UTC and how to manage permissions.
• Python/Boto3 – check the methods used in the Lambda functions (describe_instances, stop_instances, start_instances, etc.).
• Pre-commit – enable the hooks in .pre-commit-config.yaml for formatting and documentation generation.

Requirements

Name	Version
terraform	>= 1.3
aws	~> 4.0

Providers

No providers.

Modules

Name	Source	Version
ec2_scheduler_default	./modules/ec2_scheduler	n/a
rds_scheduler_default	./modules/rds_scheduler	n/a

Resources

No resources.

Inputs

Name	Description	Type	Default	Required
region	AWS region to deploy resources	string	"us-east-1"	no

Outputs

Name	Description
ec2_scheduler_lambda_arns	ARNs of the EC2 scheduler Lambda functions
rds_scheduler_lambda_arns	ARNs of the RDS scheduler Lambda functions