Moving resources from the default workspace to a new one on Terraform.

Step 1 - First things first

I'll assume that you are using remote states for two main reasons:
You should be doing this.
It's harder to move the resources, so when I explain how to do this on remote states you will be able to do this on local states.

First thing you need to do is remove your backend. You probably have something like this:

terraform {
  backend "s3" {
    bucket = "bucket-name"
    key    = "terraform.tfstate"
    region = "us-east-1"
  }
}

You don't need to delete it, just comment all these lines.

Why? 
Because we need to pull our tfstate to our local machine.

To pull the tfstate from remote to local storage we just need to run terraform init.

It will download all the modules and give you the following output:

Do you want to migrate all workspaces to "local"?
 Both the existing "s3" backend and the newly configured "local" backend support workspaces. When migrating between backends, Terraform will copy all workspaces (with the same names). THIS WILL OVERWRITE any conflicting states in the destination.
 
 Terraform initialization doesn't currently migrate only select workspaces.
 If you want to migrate a select number of workspaces, you must manually
 pull and push those states.
 
 If you answer "yes", Terraform will migrate all states. If you answer
 "no", Terraform will abort.
Enter a value:

As we don't have any other workspace yet, let's put yes and wait.
Couple seconds should be enough to get the message:

Terraform has been successfully initialized!
Now, you can do a ls terraform.state and you see the file created.

Step 2 - Setting up the workspace

Now that we already have the state file on our local storage, we can move the resources.
If you are not using remote storage, you should be using, your work starts here!

We need to create our workspace so let's run the following command:

terraform workspace new name_of_workspace

In my case I've done:

terraform workspace new qa

To validate that we don't have any resources lets do this:

terraform workspace list
  default
* qa

To check if we are in the correct workspace, then run:

terraform state list

You should get something like:

No state file was found!
State management commands require a state file. Run this command
in a directory where Terraform has been run or use the -state flag
to point the command to a specific state location.

Step 3 - Let's do magic!

You will need to pay a lot of attention here. We will use the terraform state push command.
Run:

terraform state push terraform.tfstate

If you get some error we always had the -force tag ;)

terraform state push -force terraform.tfstate

Now, let's run the terraform state list again :

terraform state list

module.qa_environment.aws_availability_zones.available
...

Step 4 - Cleaning up

We can't leave the default workspace with the same resources, we can have problems with two workspaces managing the same resources, so let's clean it!
First, we need to move to default workspace:

terraform workspace select default

Now, let's list all the resources available:

terraform state list
module.qa_environment.aws_availability_zones.available

In my case, as I only have the module qa_environment , I'll run this:

terraform state rm module.qa_environment

This will remove all nested resources.

Step 5 - Moving data to remote storage.

Let's just uncomment these lines:

terraform {
  backend "s3" {
    bucket = "bucket-name"
    key    = "terraform.tfstate"
    region = "us-east-1"
  }
}

and run

terraform init

You will be asked if want to move all data to a new remove state. Just press yes and you are good to go! :)

Quick Tip

If you are using some CI/CD tool, don't forget to add the following command as a pipeline step:

terraform workspace select environment_name

Without this, you will try to recreate all resources on default workspace and probably will get some error.