Terraform AWS Lambda Scheduler

Terraform module which allow to stop and start EC2 instances, RDS resources and AutoScaling Groups by a schedule with Lambda function.

Summary

• Features
• Getting Started
  • As Terraform module
  • For developer
• Running the tests
• Versioning
• License
• Acknowledgments

Features

• Terraform 0.12 code style
• AWS Lambda in a pure Node.js 12
• EC2 instances scheduling
• EC2 Spot instances scheduling
• RDS instances scheduling
• AutoScaling Group scheduling
• AWS CloudWatch logs for Lambda
• Multi AWS tags support
• Pagination for more than 50 items
• RDS clusters scheduling
• CloudWatch Alarm scheduling

Caveats

Spot instances have slightly different running/stopping process on AWS, so we need consider in separately.

Limitations

• Amazon EC2 Spot instances can now be stopped and started similar to On-Demand instances. This feature is only available for instances with an Amazon EBS volume as their root device.
• AWS can stop instance if it has been run with persistance request, otherwise we can only terminate it.
• AWS can't stop a Spot Instance if it is part of a fleet or launch group, Availability Zone group, or Spot block. You can only terminate them.
• The stop feature is available for persistent Spot requests and Spot Fleets with the maintain fleet option enabled. You will not be charged for instance usage while your instance is stopped.

Getting Started

As Terraform module

Copy and paste into your Terraform configuration, insert the variables, and run terraform init:

module "infra-stop-nightly" {
  source                         = "popovserhii/lambda-scheduler/aws"
  name                           = "${terraform.workspace}-stop-infra"
  aws_regions                    = ["eu-central-1"]

  cloudwatch_schedule_expression = "cron(0 17 ? * MON-SUN *)" # UTC
  schedule_action                = "stop"

  spot_schedule                  = true
  ec2_schedule                   = true
  rds_schedule                   = false
  autoscaling_schedule           = false
  cloudwatch_alarm_schedule      = false

  resource_tags = [
    {
      Key = "ToStop"
      Value = "true"
    },
    {
      Key = "Environment"
      Value = terraform.workspace
    }
  ]
} 

module "infra-start-daily" {
  source                         = "popovserhii/lambda-scheduler/aws"
  name                           = "${terraform.workspace}-stop-infra"
  aws_regions                    = ["eu-central-1"]

  cloudwatch_schedule_expression = "cron(0 07 ? * MON-FRI *)" # UTC
  schedule_action                = "start"

  spot_schedule                  = true
  ec2_schedule                   = true
  rds_schedule                   = false
  autoscaling_schedule           = false
  cloudwatch_alarm_schedule      = false

  resource_tags = [
    {
      Key = "ToStop"
      Value = "true"
    },
    {
      Key = "Environment"
      Value = terraform.workspace
    }
  ]
}

Example

NOTE: All examples stop every day from Monday to Friday at 17:00 UTC and start every day from Monday to Friday at 07:00 UTC

• AutoScaling scheduler - Create lambda functions to suspend autoscaling group with ToStop = true and TestTag = <random_value> tags and terminate its EC2 instances.
• Spot scheduler - Create lambda functions to stop Spot instance with ToStop = true and Environment = test tags.
• EC2 scheduler - Create lambda functions to stop EC2 with ToStop = true and Environment = test tags.
• EC2 Bastion scheduler - Create lambda functions to stop EC2 Bastion host with ToStop = true and Environment = test tags.
• RDS MariaDB scheduler - Create lambda functions to stop RDS MariaDB with ToStop = true tag.

Inputs

Name	Description	Type	Default	Required
name	Define name to use for lambda function, cloudwatch event and iam role	string	n/a	yes
custom_iam_role_arn	Custom IAM role arn for the scheduling lambda	string	null	no
kms_key_arn	The ARN for the KMS encryption key. If this configuration is not provided when environment variables are in use, AWS Lambda uses a default service key	string	null	no
aws_regions	A list of one or more aws regions where the lambda will be apply, default use the current region	list	null	no
cloudwatch_schedule_expression	The scheduling expression	string	"cron(0 22 ? * MON-FRI *)"	yes
schedule_action	Define schedule action to apply on resources	string	"stop"	yes
autoscaling_schedule	Enable scheduling on autoscaling resources	string	"false"	no
spot_schedule	Enable scheduling on spot instance resources	string	"false"	no
ec2_schedule	Enable scheduling on EC2 instance resources	string	"false"	no
rds_schedule	Enable scheduling on RDS resources	string	"false"	no
cloudwatch_alarm_schedule	Enable scheduleding on cloudwatch alarm resources	string	"false"	no
resource_tags	Set the tags use for identify resources to stop or start	map	[{ ToStop = "true" }]	yes

Outputs

Name	Description
lambda_iam_role_arn	The ARN of the IAM role used by Lambda function
lambda_iam_role_name	The name of the IAM role used by Lambda function
scheduler_lambda_arn	The ARN of the Lambda function
scheduler_lambda_name	The name of the Lambda function
scheduler_lambda_invoke_arn	The ARN to be used for invoking Lambda function from API Gateway
scheduler_lambda_function_last_modified	The date Lambda function was last modified
scheduler_lambda_function_version	Latest published version of your Lambda function
scheduler_log_group_name	The name of the scheduler log group
scheduler_log_group_arn	The Amazon Resource Name (ARN) specifying the log group

For developer

These instructions will get you a copy of the project up and running on your local machine for development and testing purposes.

Prerequisites

Clone the source locally:

$ git clone https://github.com/popovserhii/terraform-aws-lambda-scheduler
$ cd terraform-aws-lambda-scheduler

If you're on Debian or Ubuntu or Mint, you'll need to install NodeJS version not less 13:

Use your package manager to install NPM and NodeJS.

$ curl -sL https://deb.nodesource.com/setup_13.x | sudo bash -
$ sudo apt-get install -y npm nodejs

Install project dependencies:

$ npm install

Running the tests

At that moment only Unit tests are implemented, so you can run the tests as much as you need without bother that some resources will be created on AWS.

Unit tests

Unit tests are using:

• Mocha as JavaScript test framework
• Sinon for test spies, stubs and mocks
• Chai as a BDD/TDD assertion library
• AWSomocks as mocks for Javascript AWS-SDK services

Run the tests with:

$ npm test

Versioning

We use SemVer for versioning. For the versions available, see the tags on this repository.

License

This project is licensed under the MIT

Acknowledgments

There is a library which does almost the same, but its Lambda functions are written on Python. At the moment when I was searching for a Terraform module to stop and run my infrastructure, it didn't work correctly with Spot Instances, so there was a dilemma to write an issue and wait till the maintainer fix it, or implement it by myself. The result you can see in this repository.

As I know NodeJS it was easier for me to rewrite it and improve missing parts.

Many thanks to the author who implemented this on Python for inspiration.