1. Introduction

In this project, we automate the turning on and off of EC2 instances during working hours, helping reduce unnecessary costs. By utilizing AWS Lambda and EventBridge, we ensure that EC2 instances are only running when they are needed.

2. Project Overview

• Objective: Automatically start EC2 instances at 9 AM and stop them at 5 PM.
• Tools Used: AWS Lambda, EventBridge, and Boto3.
• Cost Optimization: This automation helps save money by only keeping EC2 instances running during work hours.

3. Core Logic Behind the Automation

• Tags for Automation: The instances that need to be started and stopped automatically are tagged when they are created with the following:

  • Key: AutoStop
  • Value: true

  

• Working Hours Logic:

  • At 9:00 AM, Lambda starts all instances with the AutoStop=true tag.
  • At 5:00 PM, Lambda stops those instances.

4. Step-by-Step Setup

Step 1: Start Script (Lambda to Start Instances)

This script is triggered at 9:00 AM to start the EC2 instances that were stopped outside of working hours.

import boto3
ec2 = boto3.resource('ec2')
instance_id = []

def stop_instance(instance_id):
    ec2.instances.filter(InstanceIds=instance_id).start()

# Retrieve stopped instances
def filtered_instances():
    instances = ec2.instances.filter(
        Filters=[
            {
                'Name': 'instance-state-name',
                'Values': ['stopped']
            }
        ]
    )
    return instances

def lambda_handler(event, context):
    instance_id = []
    target_tag_key = 'AutoStop'
    target_tag_value = 'true'
    instances = filtered_instances()

    # Loop through each instance
    for instance in instances:
        if instance.tags:
            for tag in instance.tags:
                if tag['Key'] == target_tag_key and tag['Value'] == target_tag_value:
                    instance_id.append(instance.id)
    stop_instance(instance_id)

• Purpose: The script filters out EC2 instances that are tagged for auto-stop, checks for the AutoStop=true tag, and starts those instances.
• Boto3 Resource: Used to interact with AWS EC2 services and filter instances based on state and tags.

Step 2: Stop Script (Lambda to Stop Instances)

At 5:00 PM, the following script stops the running EC2 instances that are tagged for automation.