💲💲 SAVE YOUR MONEY 💲💲

You can save your money by starting EC2 instances only when you really need it. This for a negligible amount, less than $1 a year, needed for the small AWS Lambda. This Node.js application give you the ability to auto stop and start EC2 instances which are tagged with auto:stop and auto:start.

Inspired by existing python and nodejs applications. In particular this one : https://schen1628.wordpress.com/2014/02/04/auto-start-and-stop-your-ec2-instances/

• cron-parser: https://www.npmjs.com/package/cron-parser
• aws-sdk: https://www.npmjs.com/package/aws-sdk
• node-aws-lambda: https://github.com/ThoughtWorksStudios/node-aws-lambda

• Auto-stop instance every day at 7pm : 0 19 * * *
• Auto-start instance every day at 8:30am : 0 30 8 * * *

With a default margin of 15 minutes, EC2 instances will be stop between 7pm and 7:15pm and start between 8:15am and 8:30am. The margin time can be set with a variable in the source code. It must be linked to the lambda schedule settings.

Values of tags are CRON expressions : http://www.cronmaker.com/. Seconds are optionals.

❗ Never forget that AWS Lambda works with UTC Time ❗

create a lambda with the AWS console (https://eu-west-1.console.aws.amazon.com/lambda/):

• Choose "Blank function" blueprint
• Configure a trigger:
  • choose CloudWatch Events
  • create a new rule, give it a significant name and description
  • choose rule type: "Schedule expression"
  • insert a schedule expression: rate(5 minutes) or what you need...
  • click "Enable trigger" now or later if you need test

• Click "Next"
• Configure function: give a name and a description for the lambda
• Runtime: choose Node.js 6.10
• Lambda function code: let "Edit code inline"

• Lambda function handler and role:

  • Handler: let "index.handler"
  • Role: choose "create a custom role":
  • In the opened page, choose "Create a new IAM role"
  • Give it a name
  • Click View policy document
  • Click on the Edit button, confirm, and paste this policy:

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

  • Don't forget to click on the Allow

  

• Advanced settings:

  • let the default memory configuration (128Mo)
  • Adjust the time-out to 1 minute

  

  • If you have a specific VPC configuration, you can set it:

  

• Click on Next

• Click on Create function

1. Clone this repository

2. Run npm install

3. Add a file: lambda-config.js

   and fill the necessary informations

   module.exports = {
       region: 'YOUR_REGION',
       functionName: 'YOUR_LAMBDA_NAME'
   };

   You can create the lambda "on the fly" with more parameters. If you need it, go to https://github.com/ThoughtWorksStudios/node-aws-lambda

   Thanks to ThoughtWorksStudios for this great module !

4. If you have an AWS profile with the necessary rights installed, you can deploy your lambda with the deploy gulp task.

   

   It's possible to fill the credentials directly in the lambda-config.js file .

5. Back to the AWS Lambda console

   Now, you can view the uploaded code (a refresh can be needed):

   

   And you can test the Lambda:

   

   If all is OK, after some seconds you can see this output:

   

   Click on logs to view details with CloudWatch

That's all ☺️