📘 Documentation: Automate EC2 Start/Stop with AWS Lambda and EventBridge:

📌 Objective:

To automatically start or stop an EC2 instance using AWS Lambda and EventBridge (CloudWatch Events).

🛠️ Prerequisites:

• AWS Account
• One running EC2 instance
• IAM Role with proper permissions
• Basic knowledge of AWS Lambda and IAM

🧾 Step-by-Step Setup:

Steps

1.Create IAM Role for Lambda

• Go to IAM > Roles > Create role

2.Navigate to IAM → Policies → Create policy

Add Permission policy → Use JSON policy enabling EC2 start/stop and log access:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "ec2:StartInstances",
        "ec2:StopInstances",
        "ec2:DescribeInstances"
      ],
      "Resource": "*"
    },
    {
      "Effect": "Allow",
      "Action": [
        "logs:CreateLogGroup",
        "logs:CreateLogStream",
        "logs:PutLogEvents"
      ],
      "Resource": "*"
    }
  ]
}

3.Create lambda function

• Lambda → Create Function → Author from scratch

• Runtime: Python 3.x

• Change Default execution role--use existing

• Existing role -->select role name

• Created function✅

• Use this code

• 👉 view Code

• Delpoy it ✅

IMP- Edit the Instance id in that

4.Test

• Test manually with

{}

5.Configuration

• timeout
• 30 sec
• configured ✅

6. Configure EventBridge Schedule Rules

• Go to EventBridge → Scheduler → Create schedule

• Choose a cron expression (e.g., cron(0 3 * * ? *) for 3 AM UTC)

• 📘 Explanation:

3 → minute (03)

11 → hour (11 AM UTC)

31 → day of month (31st)

7 → July

? → ignore day-of-week

2025 → year

Target: select relevant Lambda function

Pass custom payload like

{ "action": "start/stop" }

Created Function Rule - Update Rule ✅

7. Go to the lambda function

• Go to configuration
• Add Trigers:
• EventBridge (CloudWatch Events): ec2-stop-rule
• EventBridge (CloudWatch Events): ec2-start-rule