EC2 Auto Shutdown and Start

As a software engineering team, we are working with Amazon EC2 instances on a daily basis While EC2 instances are great for running applications and services but its important to properly manage our instances to avoid unnecessary costs and resource consumption. One way to do this is by automating the shutdown and start of your EC2 instances

This project automates the start and stop of AWS EC2 instances based on scheduled CloudWatch Events using an AWS Lambda function. It leverages Ruby AWS SDK for creating the Lambda function, CloudWatch Events, and EC2 instance management. You can configure the instance and schedule using the CLI.

The project allows you to:

• Create a Lambda function that automatically starts or stops EC2 instances based on their current state (i.e., running or stopped).
• Schedule EC2 instance start/stop operations using CloudWatch Events.
• Manage the schedule and EC2 instance operations through a Ruby-based CLI.

flowchart TD
    A[User - Command Line Interface] -->|Configure CloudWatch Events for each EC2 Instance| B[CloudWatch Events]
    B -->|Trigger Event based on Schedule and Instance Name| C[Lambda Function]
    C -->|Executes Script based on Condition| D{Start or Stop EC2 Instance}
    D -->|Start| E[Start EC2 Instance]
    D -->|Stop| F[Stop EC2 Instance]

    subgraph AWS
      E
      F
      G[CloudWatch Logs] --> C
    end
    
    A -->|Monitor Logs| G
    B --> G
    
    style A fill:#f96,stroke:#333,stroke-width:2px;
    style D fill:#ff9,stroke:#333,stroke-width:2px;
    style E fill:#bbf,stroke:#333,stroke-width:2px;
    style F fill:#bbf,stroke:#333,stroke-width:2px;
    style C fill:#bbf,stroke:#333,stroke-width:2px;
    style G fill:#f66,stroke:#333,stroke-width:2px;

• Lambda function: Automatically manages the start and stop of EC2 instances.
• CloudWatch Events: Schedules based on cron expressions to run the Lambda function at specific times.
• CLI Interface: Easy-to-use interface for setting up the Lambda function and managing EC2 instance operations.

• AWS CLI: Ensure that the AWS CLI is installed and configured with access to your AWS account.
• Ruby 3.x: The project requires Ruby version 3.x. Install Ruby using a version manager like RVM or rbenv.
• AWS SDK for Ruby: The project uses aws-sdk-ec2 and aws-sdk-cloudwatchevents gems.
• IAM Permissions: Ensure the AWS user you are using has permissions to:
  • Manage EC2 instances.
  • Create CloudWatch Events.
  • Create and manage Lambda functions.
  • Create and assign IAM roles and policies.

git clone [https://github.com/maniSHarma7575/hibernate.git](https://github.com/maniSHarma7575/hibernate.git)
cd hibernate

Make sure you have the required gems by running:

bundle install

Create a .env file at the root of your project and configure your AWS credentials:

AWS_ACCESS_KEY_ID=<your-access-key-id>
AWS_SECRET_ACCESS_KEY=<your-secret-access-key>
AWS_REGION=<your-aws-region>
ACCOUNT_ID=<your-account-id>

The project includes a CLI to manage the setup of the Lambda function and CloudWatch Events. Here’s how you can use it:

Run the following command to set up the Lambda function:

bin/hibernate setup

This command will:

• Create an IAM role (if it doesn't exist).
• Create the Lambda function.
• Attach the necessary permissions for managing EC2 instances.

Use the following command to manage EC2 instances with scheduled start/stop times:

bin/hibernate node --instance-name=<instance_name> --start-expression="<cron>" --stop-expression="<cron>"

• --instance-name=<instance_name>: The EC2 instance name tag.
• --start-expression=<cron>: The cron expression for when to start the instance (optional, but either start-expression or stop-expression is required).
• --stop-expression=<cron>: The cron expression for when to stop the instance (optional, but either start-expression or stop-expression is required).

Note: You must provide at least one of --start-expression or --stop-expression. Both can be provided, but at least one is required.

bin/hibernate node --instance-name=my-instance --start-expression="34 16 * * ? *" --stop-expression="0 22 * * ? *"

This schedules the instance to start at 4:34 PM UTC and stop at 10:00 PM UTC.

Use the following command to remove the scheduled start/stop rules for an EC2 instance:

bin/hibernate remove --rule=<Rule name>

• --rule=<rule name>: Specify the rule you want to delete from the list of rules.

bin/hibernate remove --rule=StopInstanceRule-i-02e532fa1faefcbeb

This will remove the CloudWatch rule that stops the instance at 10:00 PM UTC.

To list all scheduled start/stop rules for all EC2 instances, you can simply run:

bin/hibernate list

To list scheduled rules for a specific EC2 instance, use the following command:

bin/hibernate list --instance-name=<instance_name> [--start-instance=true] [--stop-instance=true]

Parameters:

• --instance-name=<instance_name>: The name tag of the EC2 instance whose rules you want to list (optional).
• --start-instance=true: (Optional) Include this flag to list only the start rules.
• --stop-instance=true: (Optional) Include this flag to list only the stop rules.

Example:

bin/hibernate list --instance-name=my-instance --start-instance=true

This command lists all scheduled start rules for the specified instance.

CloudWatch Events uses the following format for cron expressions:

cron(Minutes Hours Day-of-month Month Day-of-week Year)

• Example: cron(34 16 * * ? *) runs every day at 4:34 PM UTC.

• Setup Lambda: bin/hibernate setup
• Schedule Start/Stop: bin/hibernate node --instance-name=<instance_name> --start-expression=<cron> --stop-expression=<cron>
• Remove Start/Stop Rules: bin/hibernate remove --rule=<Rule name>
• List Scheduled Rules:
  • For all instances: bin/hibernate list
    • For a specific instance: bin/hibernate list [--instance-name=<instance_name>] [--start-instance=true] [--stop-instance=true]

• AWS Cron Expressions

Feel free to submit pull requests or report issues. We welcome contributions to enhance the functionality of the project.

This project is licensed under the MIT License. See the LICENSE file for details.

• Ensure your AWS credentials are properly configured in the .env file.
• Test the Lambda function thoroughly before deploying it to production environments.