Master Terraform: A cheat sheet for infrastructure automation

Welcome to the ultimate Terraform cheat sheet! If you’re a developer looking to take control of your infrastructure, you’ve come to the right place. With this cheat sheet in hand, you’ll be able to accomplish basic tasks with Terraform in no time. From creating plans and applying them to importing and managing your infrastructure, this cheat sheet has got you covered. So, whether you’re new to Terraform or just need a quick reference, don’t hesitate to use this cheat sheet to make your life easier. Just remember, with Terraform, the world is your oyster!

Terraform cheat sheet

CLI commands

Initialize Terraform: terraform init
Create a plan: terraform plan
Apply the plan: terraform apply
Destroy the infrastructure: terraform destroy
To import an existing infrastructure: terraform import [resource_name] [resource_id]
To see the state of the infrastructure: terraform show
To list all the resources that Terraform is managing: terraform state list
To get detailed information about a specific resource: terraform state show [resource_name]
To validate the syntax of the Terraform files: terraform validate
To see a list of all the available Terraform providers: terraform providers
To see the version of Terraform currently installed: terraform version
To override a variable value from the command line: terraform apply -var '[variable_name]=[value]

TF file language

To create a new Terraform module: terraform module new [module_name]
To use a module in the Terraform configuration: module "[module_name]" {}
To pass variables to a module: module "[module_name]" { [variable_name] = [variable_value] }
To use a different version of a provider: provider "[provider_name]" { version = "[version]" }
To create and edit a Terraform variable file: terraform.tfvars
To reference a variable in the Terraform configuration: var.[variable_name]

Worth noting

Before running the terraform apply command, check the plan using terraform plan.
terraform destroy will delete all the resources defined in the current configuration.
The terraform import command can only import resources that are already created and exist in the target provider.
When importing, you’ll need to generate the config file of the resource you import.
terraform state commands inspect the current state of the infrastructure managed by Terraform.
Before initializing Terraform, remember to specify the provider and backend configuration in the main.tf file.
The terraform validate command is used to validate the syntax of the Terraform files; it’s a good practice to run it before applying any change.
terraform.tfvars is used to store sensitive data such as credentials, and it’s better not to include it in the version control.

Advanced Terraform tips and tricks

To save the current state of the infrastructure to a file: terraform state pull > [file_name].tfstate
To load the state from a file: terraform state push [file_name].tfstate
To refresh the state and update it with the current infrastructure: terraform refresh
To generate an execution plan and save it to a file: terraform plan -out [file_name].plan
To apply an execution plan from a file: terraform apply [file_name].plan
To see the current state: terraform show
To return a detailed exit code to determine if changes exist between the current infrastructure and the current plan: terraform plan -detailed-exitcode
- 0 = no changes; succeeded with empty diff
- 1 = Error with plan
- 2 = Succeeded, with changes to be made (non-empty diff)
To generate a visual representation of either a configuration or execution plan: terraform graph | dot -Tpng > graph.png

Terraform best practices

Keep the Terraform files in version control
Use modules to organize the Terraform files
Use variables to make the Terraform files more reusable
Use terraform state commands to inspect and manage the state of the infrastructure
Use Terraform workspaces to manage different environments (e.g. dev, staging, production)
Use Terraform’s built-in validation checks, such as terraform validate, to catch errors early
Use a separate backend configuration to store the state remotely to avoid loss and conflicts.
Use terraform plan -detailed-exitcode to check for changes before applying.
Use the terraform import command to import existing resources and keep track of them in the state.
Use terraform taint to mark a specific resource for recreation.
- This command is useful for operational resources that are experiencing internal problems not managed by terraform.
- For example, a VM machine may be operational, but the software running on the instance has crashed
While terraform state list is excellent for seeing all infrastructure that exists, the list will be large and will be difficult to parse out information
- Ensure that you filter by resource or by module to get back helpful information
Use terraform graph | dot -Tpng > graph.png to visualize configuration or execution plans

Learn more about Terraform, infrastructure as code, and CI/CD

In conclusion, this cheat sheet is a valuable tool for developers and DevOps professionals looking to take control of their infrastructure with Terraform. It covers basic tasks such as creating plans, applying them, and managing state, as well as advanced tips and tricks and best practices to help you make the most of this powerful tool.

However, this cheat sheet is not exhaustive, and there will always be more to learn about Terraform and infrastructure management. For more information, I recommend checking out the following resources:

These resources provide in-depth information and guidance on using Terraform and other infrastructure management tools and best practices for CI/CD. By following the tips and tricks outlined in this cheat sheet and diving deeper into these resources, you’ll be well on mastering Terraform and automating your infrastructure.

Want to share your thoughts on this post, or have a suggestion for how we can improve? Leave a comment below!

We’ll leave you today with a poem about Terraform that we generated using ChatGPT:

Terraform, oh Terraform,
A tool that’s quite the norm,
With this cheat sheet in your hand,
You’ll be a master of the land.

Create plans with such grace,
Manage state with a steady pace,
Advanced tips, tricks galore,
Infrastructure automation, nothing to deplore.

So come on, give it a try,
Terraform’s the tool; give it a try,
And soon you’ll see,
A master of infrastructure, you’ll be.