Resource Targeting

In this lesson, you’ll learn how to use resource targeting with OpenTofu’s plan and apply commands to update individual resources without affecting the rest of your infrastructure.

Example Configuration

Below is a sample HCL configuration that generates a random string and launches an AWS EC2 instance tagged with that string:

resource "random_string" "server-suffix" {
  length  = 6
  upper   = false
  special = false
}

resource "aws_instance" "web" {
  ami           = "ami-06178cf087598769c"
  instance_type = "m5.large"
  tags = {
    Name = "web-${random_string.server-suffix.id}"
  }
}

The aws_instance.web resource uses the interpolation ${random_string.server-suffix.id} to append the generated suffix to the Name tag.

Applying Changes Normally

If you change the random string’s length from 6 to 5 and run:

$ tofu apply

OpenTofu will plan and apply updates for both resources because the EC2 tag depends on the random string:

Plan: 1 to add, 1 to change, 1 to destroy.

Enter a value: yes
random_string.server-suffix: Destroying... [id=6r923x]
random_string.server-suffix: Creation complete after 0s [id=nglmpo]
aws_instance.web: Modifying... [id=i-67428769e06ae2901]
Apply complete! Resources: 1 added, 1 changed, 1 destroyed.

Targeting a Single Resource

To update only the random string and leave the EC2 instance untouched, use the -target flag:

$ tofu apply -target=random_string.server-suffix

OpenTofu will generate a plan for just that resource:

OpenTofu will perform the following actions:

  # random_string.server-suffix must be replaced
-/+ resource "random_string" "server-suffix" {
    ~ id      = "bl12qd" -> (known after apply)
    ~ length  = 6 -> 5 # forces replacement
}

Plan: 1 to add, 0 to change, 1 to destroy.

Warning: Resource targeting is in effect

Enter a value: yes
random_string.server-suffix: Destroying... [id=6r923x]
random_string.server-suffix: Creation complete after 0s [id=nglmpo]

Warning: Applied changes may be incomplete
Apply complete! Resources: 1 added, 0 changed, 1 destroyed.

Using resource targeting can leave your state incomplete. Reserve this feature for urgent fixes or small, isolated changes.

CLI Commands Reference

Command	Description
`tofu plan`	Preview all changes before applying them
`tofu apply`	Apply all planned changes
`tofu apply -target=<RESOURCE_TYPE>.<NAME>`	Apply changes only to the specified resource

Course Introduction

Introduction to Infrastructure as Code

OpenTofu Basics

OpenTofu State

Working with OpenTofu

Remote State

OpenTofu Provisioners

OpenTofu Import, Tainting Resources and Deubugging

OpenTofu Modules

OpenTofu Functions and Conditional Expressions

OpenTofu: Beyond Basics

Course Conclusion

Getting Started with OpenTofu

Resource Targeting

Example Configuration

Applying Changes Normally

Targeting a Single Resource

CLI Commands Reference

Links and References

Watch Video

​Example Configuration

​Applying Changes Normally

​Targeting a Single Resource

​CLI Commands Reference

​Links and References

Watch Video

Example Configuration

Applying Changes Normally

Targeting a Single Resource

CLI Commands Reference

Links and References