How to disable AWS instance destroy with Terraform?

Protect your AWS infrastructure in Production from accidental deletion #

Deleting infrastructure is perfectly normal during development, but once you are in production it is important to protect some instances and resources from being accidentally destroyed by Terraform.

Updates:

• 2020 Jul 03: Updated to Terraform 0.12
• 2026 Oct 05: Added the prevent_destroy lifecycle setting and reviewed the text for current Terraform and OpenTofu versions

Some might say that since we are using Terraform and infrastructure as code, the infrastructure can be recreated in minutes (depending on size and Cloud provider speed), and that is true, so it is not a problem to delete an instance, a database or a VPC, but I believe that once you are in production, it is not acceptable to have your systems and applications down.

Recreating an instance is really easy and a fast operation using AWS and Terraform, but then you have to install software, configure and deploy the application, maybe load data from backup and that can be really time consuming.

In a world of micro-services and cloud-native applications, adding instances and removing them from the pool is fast and desirable, but not everything is a micro-service or has many clones for high availability and fail-over.

Think, for example, of a Cassandra node or an Elasticsearch node, or a traditional Database node.

Your responsibility is to protect those nodes and only in the case of a hard failure or a planned maintenance replace them.

How to prevent infrastructure destroy in Terraform #

How do you protect AWS instances from being destroyed by Terraform, or by a user through the AWS control panel or other tools?

AWS instances have some configuration properties for this:

• Preserve AWS EBS volumes on Termination
• Enable AWS EC2 Instance Termination Protection
• Enable AWS RDS instance Deletion protection (Available Sep 2018)

By default, all AWS EBS root device volumes are deleted when the instance terminates. EC2 and RDS instances can be terminated using the AWS API or the AWS control panel.

To change this behavior, in Terraform I like to include a global variable that indicates if the infrastructure is in production or not.

terraform.tfvars

is_production = false

The variable is_production will be false during the development of Terraform plans and will be changed to true as soon as the infrastructure is in production or live.

Disable EC2 instance deletion #

When creating instances, the value of is_production will be used to set the disable_api_termination and delete_on_termination arguments as shown on the example.

aws_ec2_pro_srv1234.tf

resource "aws_instance" "srv1234" {
 ....
 disable_api_termination = var.is_production ? true : false
 instance_initiated_shutdown_behavior = "stop"
 ...
 root_block_device {
 ...
 delete_on_termination = var.is_production ? false : true
}
...
}

If this configuration is in place, the is_production variable is true and the infrastructure has been deployed, you will have to use the AWS console or edit your Terraform resources to change the values of instance_initiated_shutdown_behavior to be able to destroy the instances.

A third configuration property sets the behavior for an instance shutdown, the default behavior is to stop the instance but it can be changed to destroy if needed.

Disable RDS instance deletion #

It is also possible to prevent the deletion of a database instance by using the property deletion_protection of RDS. The default value of the property if unspecified is false.

aws_rds_pro_rds789.tf

resource "aws_db_instance" "rds789" {
 ....
 deletion_protection  = var.is_production ? true : false
 ...
}

Database deletion protection is available in RDS since September 2018.

Controlling these variables can avoid many problems, like when having a Multi-AZ RDS database that has changed availability zone for maintenance or an upgrade from what is specified in Terraform local state. In this case, Terraform thinks that the database needs to be recreated, in the “configured” availability zone and proceeds to destroy the database if the plan is applied. Having deletion_protection enabled will prevent the deletion.

Prevent destroy in Terraform and OpenTofu: lifecycle #

The properties above are enforced by AWS, for any tool or user. Terraform and OpenTofu also have their own protection, the prevent_destroy argument of the lifecycle block: any plan that would destroy the resource, including terraform destroy, fails with an error.

resource "aws_db_instance" "ditwl-rds-001" {
  # ...
  deletion_protection = var.is_production

  lifecycle {
    prevent_destroy = true
  }
}

Be aware that prevent_destroy only works while the resource is in the code: if the resource block is removed, Terraform destroys the resource. The argument also cannot be set from a variable, so use it together with deletion_protection and the AWS termination protection. It is used, for example, in the Terraform Backends tutorial to protect the bucket of the state. Other useful lifecycle arguments are create_before_destroy and ignore_changes.

See also AWS EC2 and AWS RDS.