No need to run in terror from Terraform. Close that search engine tab and check out our ultimate Terraform Cheat Sheet for all the basic commands you need on hand to get the most from this awesome, intuitive IaC tool. Also, why not showcase your IaC skills with a Terraform Certification.
At A Cloud Guru, we have in-depth courses on Terraform — from deploying to AWS with Terraform to deploying resources to GCP with Terraform and using Terraform to create infrastructure in Azure. But sometimes all you need is a simple, handy reference to get stuff done. We’ve got you covered!
Table of Contents
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What is Terraform?
Infrastructure as Code (IaC) is a key part of a balanced cloud breakfast. And when it comes to IaC tools, Terraform is one of the top tools out there. (Which IaC tool is right for you? Check out our guide to IaC on AWS.)
Terraform came onto the scene in 2014 to orchestrate infrastructure as code. It first targeted AWS but has grown to play nicely with a large ecosystem of modules, including Google Cloud Platform (GCP), Microsoft Azure, Oracle Cloud Infrastructure, and Alibaba Cloud. In fact, multi-provider support is one of the main selling points of Terraform.
Terraform introduced its own DSL, called Hashicorp Configuration Language (HCL). On the surface, it feels like a more human-friendly JSON, which is also natively supported within Terraform.
HCL is a powerful configuration language that helps use Terraform to the highest potential!
Want to learn more about HCL2? Test your HCL2 skills by fixing an inaccurately written HCL2 Packer template with our hands-on lab!
Terraform Command Lines
Terraform CLI tricks
terraform -install-autocomplete#Setup tab auto-completion, requires logging back in
Format and Validate Terraform code
terraform fmt#format code per HCL canonical standard
terraform validate#validate code for syntax
terraform validate -backend=false#validate code skip backend validation
Initialize your Terraform working directory
terraform init#initialize directory, pull down providers
terraform init -get-plugins=false#initialize directory, do not download plugins
terraform init -verify-plugins=false#initialize directory, do not verify plugins for Hashicorp signature
Plan, Deploy and Cleanup Infrastructure
terraform apply --auto-approve#apply changes without being prompted to enter “yes”
terraform destroy --auto-approve#destroy/cleanup deployment without being prompted for “yes”
terraform plan -out plan.out#output the deployment plan to plan.out
terraform apply plan.out#use the plan.out plan file to deploy infrastructure
terraform plan -destroy#outputs a destroy plan
terraform apply -target=aws_instance.my_ec2#only apply/deploy changes to the targeted resource
terraform apply -var my_region_variable=us-east-1#pass a variable via command-line while applying a configuration
terraform apply -lock=true#lock the state file so it can’t be modified by any other Terraform apply or modification action(possible only where backend allows locking)
terraform apply refresh=false# do not reconcile state file with real-world resources(helpful with large complex deployments for saving deployment time)
terraform apply --parallelism=5#number of simultaneous resource operations
terraform refresh#reconcile the state in Terraform state file with real-world resources
terraform providers#get information about providers used in current configuration
terraform workspace new mynewworkspace#create a new workspace
terraform workspace select default#change to the selected workspace
terraform workspace list#list out all workspaces
Terraform State Manipulation
terraform state show aws_instance.my_ec2#show details stored in Terraform state for the resource
terraform state pull > terraform.tfstate#download and output terraform state to a file
terraform state mv aws_iam_role.my_ssm_role module.custom_module#move a resource tracked via state to different module
terraform state replace-provider hashicorp/aws registry.custom.com/aws#replace an existing provider with another
terraform state list#list out all the resources tracked via the current state file
terraform state rm aws_instance.myinstace#unmanage a resource, delete it from Terraform state file
Terraform Import And Outputs
terraform import aws_instance.new_ec2_instance i-abcd1234#import EC2 instance with id i-abcd1234 into the Terraform resource named “new_ec2_instance” of type “aws_instance”
terraform import 'aws_instance.new_ec2_instance' i-abcd1234#same as above, imports a real-world resource into an instance of Terraform resource
terraform output#list all outputs as stated in code
terraform output instance_public_ip# list out a specific declared output
terraform output -json#list all outputs in JSON format
Terraform Miscelleneous commands
terraform version#display Terraform binary version, also warns if version is old
terraform get -update=true#download and update modules in the “root” module.
Terraform Console(Test out Terraform interpolations)
echo 'join(",",["foo","bar"])' | terraform console#echo an expression into terraform console and see its expected result as output
echo '1 + 5' | terraform console#Terraform console also has an interactive CLI just enter “terraform console”
echo "aws_instance.my_ec2.public_ip" | terraform console#display the Public IP against the “my_ec2” Terraform resource as seen in the Terraform state file
Terraform Graph(Dependency Graphing)
terraform graph | dot -Tpng > graph.png#produce a PNG diagrams showing relationship and dependencies between Terraform resource in your configuration/code
Terraform Taint/Untaint(mark/unmark resource for recreation -> delete and then recreate)
terraform taint aws_instance.my_ec2#taints resource to be recreated on next apply
terraform untaint aws_instance.my_ec2#Remove taint from a resource
terraform force-unlock LOCK_ID#forcefully unlock a locked state file, LOCK_ID provided when locking the State file beforehand
terraform login#obtain and save API token for Terraform cloud
terraform logout#Log out of Terraform Cloud, defaults to hostname app.terraform.io
The 10 most useful Terraform commands
A key part of using Terraform is learning to use the Terraform CLI by understanding the configurations.
Here are the 10 most common Terraform commands in the AWS CLI to help you navigate and use the powerful tool and started with Terraform.
So if you’ve got your Terraform binary installed and you’re ready to rock and roll, now’s a good time to familiarize yourself with the Terraform commands you’ll use most.
When you need a quick reference guide, you can always pull up Terraform’s built-in command-line documentation. There are a couple of commands for doing that:
The resulting help page will have the main commands at the top, followed by the less common or more complex commands below.
You can also enter the terraform command and then a subcommand with
--help to pull up a list of commands that are specific to that subcommand. Let’s do a walkthrough of the 10 Terraform commands you may end up using the most.
When I’ve finished my Terraform configuration, I want to make sure that everything is formatted correctly, so I run the
fmt command first. This command reformats your configuration in the standard style, so it’ll make sure that the spacing and everything else is formatted correctly. If it comes back blank, that means the configuration files within your working directory are already correctly formatted. If it does format a file, it will let you know what file it touched.
After you use the
format command, you’ll want to initialize your working directory to prepare it for what you need. The
init command looks at your configuration files and determines which providers and modules it needs to pull down from the registry to allow your configuration to work properly.
Once you’ve initialized the directory, it’s good to run the
validate command before you run
apply. Validation will catch syntax errors, version errors, and other issues. One thing to note here is that you can’t run
validate before you run the
init command. You have to initialize the working directory before you can run the validation.
Next, it’s always a good idea to do a dry run of your plan to see what it’s actually going to do. You can even use one of the subcommands with
terraform plan to output your plan to apply it later.
And then of course you have your
apply command, which is one of the commands you’re going to use the most. This is the command that deploys or applies your configuration to a provider.
destroy command, obviously, will destroy your infrastructure — or, when used with the
target flag, individual resources within your infrastructure.
If you’ve put together a good output variable file, you can use the
output command to make those defined outputs to display certain information. For example, if you’re deploying EC2 instances, you can output tag names, instance names, instance IDs, the IP of the instance, and so on. You can gather some really good information that makes it simple to look up later. And if you’re working as a team, people coming behind you can use the
output command to figure things out and get up to speed.
show command shows the current state of a saved plan, providing good information about the infrastructure you’ve deployed. For example, if you have an EC2 instance or a VM deployed in your configuration, it’ll show you the state that it’s in — if it’s up and ready or if it’s being terminated. It also provides useful information like IP addresses.
Another good way to check your work is to use the
state command. If you use
state and then the subcommand
list, it’ll give you a consolidated list of the resources that are being managed by your configuration. If you are moving your Terraform instance, such as from a local instance to a remote backup, you would use the
state mv command. And just like the
show command, there’s a
state show command that shows a resource in the state. You can also remove instances from a state by using the
state rm command.
You’ll use the
version command quite a bit to check your Terraform version, especially if you have any version conflicts. Sometimes providers work only with certain versions of Terraform, so if you’re defining those versions within your configuration, you’ll need to use the
version command here and there.
Those are some of the most popular Terraform commands. Keep in mind that
-h is a very handy way to quickly look up commands when you’re not 100% sure how to use one or what it does, especially when you’re getting started. Take a look at it when you get a chance!
Jesse Hoch and Moosa Khalid contributed to this post.
Learn the basics of Terraform
Want to learn more about getting the most out of Terraform? Check out ACG’s course Deploying to AWS with Terraform and Ansible.