How to Execute Terraform Actions Without the Interactive Prompt

TLDR

You can bypass Terraform's interactive prompts by using the -auto-approve flag for apply and destroy commands. This is useful for automation and CI/CD pipelines.

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Terraform's interactive prompts are designed to prevent accidental changes to your infrastructure. However, in automated workflows, such as CI/CD pipelines, these prompts can be a hindrance. This guide will show you how to execute Terraform actions without the interactive prompt.

Why Automate Terraform Actions?

• Efficiency: Automating Terraform actions saves time and reduces manual effort.
• Consistency: Ensures that infrastructure changes are applied in a predictable manner.
• Integration: Necessary for CI/CD pipelines and other automated workflows.

Using the -auto-approve Flag

The -auto-approve flag skips the interactive approval step for terraform apply and terraform destroy. This is particularly useful in scripts and pipelines.

Example: Applying Changes

To apply changes without confirmation, use the following command:

terraform apply -auto-approve

This command applies the Terraform configuration without asking for confirmation.

Example: Destroying Resources

To destroy resources without confirmation, use:

terraform destroy -auto-approve

This command destroys all resources managed by the Terraform configuration without requiring confirmation.

Automating Variable Inputs

In addition to bypassing prompts, you may need to provide variable values non-interactively. Use a .tfvars file or the -var flag.

Using a .tfvars File

Create a file named terraform.tfvars with your variable values:

aws_region = "us-east-1"
instance_type = "t2.micro"

Terraform automatically loads this file during execution.

Using the -var Flag

You can also pass variables directly in the command:

terraform apply -var="aws_region=us-east-1" -var="instance_type=t2.micro" -auto-approve

Disabling Interactive Prompts Globally

If you want to disable interactive prompts for all Terraform commands, set the TF_INPUT environment variable to false.

Example

Here's how to set the environment variable and run Terraform commands:

export TF_INPUT=false
terraform apply -auto-approve

This approach is useful for environments where you want to enforce non-interactive behavior.

Best Practices

• Use with Caution: Skipping prompts can lead to unintended changes. Always review your plan before applying.
• Combine with terraform plan: Run terraform plan to preview changes before applying them.
• Secure Variable Files: If using .tfvars files, ensure they are not exposed in version control.

By automating Terraform actions and bypassing interactive prompts, you can simplify your workflows and integrate Terraform into your CI/CD pipelines effectively.