instance-terminator

A AWS Lambda function to automatically terminate hosts on autoscaling groups - using Terraform.

This will run periodically and identify autoscaling groups tagged with can-be-terminated = 'true' and terminate the oldest instance, see the instance-terminator for more details

Rationale

This was created out of the need to do a rolling update of our autoscaling groups when updating the AMI.

We run immutable infrastructure, so patching our servers involves creating a new AMI and rebuilding our hosts, this function will do this over a number of days (or more frequently if desired).

In addition to this we aim to provide a highly available infrastructure that can continue to work when nodes are lost, so regularly terminating nodes will help highly issues quickly.

Usage

To use this module in your Terraform definition, add the following:

provider "external" {
  version = "~> 1.0"
}

module "instance_terminator" {
  source = "github.com/WealthWizardsEngineering/instance-terminator-terraform"
}

Configuration

• lambda_schedule - the schedule for the Lambda function, see the Lambda documentation for details