remote

The remote backend is unique among all other Terraform backends because it can both store state snapshots and execute operations for HCP Terraform's CLI-driven run workflow. It used to be called an "enhanced" backend.

When using full remote operations, operations like terraform plan or terraform apply can be executed in Terraform Cloud's run environment, with log output streaming to the local terminal. Remote plans and applies use variable values from the associated HCP Terraform workspace.

You can also use HCP Terraform with local operations, in which case only state is stored in the HCP Terraform backend.

Command Support

The remote backend supports the following Terraform commands:

• apply
• console (supported in Terraform >= v0.11.12)
• destroy
• fmt
• get
• graph (supported in Terraform >= v0.11.12)
• import (supported in Terraform >= v0.11.12)
• init
• output
• plan
• providers
• show
• state (supports all sub-commands: list, mv, pull, push, rm, show)
• taint
• untaint
• validate
• version
• workspace

Workspaces

The remote backend can work with either a single remote HCP Terraform workspace, or with multiple similarly-named remote workspaces (like networking-dev and networking-prod). The workspaces block of the backend configuration determines which mode it uses:

• To use a single remote HCP Terraform workspace, set workspaces.name to the remote workspace's full name (like networking-prod).

• To use multiple remote workspaces, set workspaces.prefix to a prefix used in all of the desired remote workspace names. For example, set prefix = "networking-" to use HCP Terraform workspaces with names like networking-dev and networking-prod. This is helpful when mapping multiple Terraform CLI workspaces used in a single Terraform configuration to multiple HCP Terraform workspaces.

The backend configuration requires either name or prefix. Omitting both or setting both results in a configuration error.

If previous state is present when you run terraform init and the corresponding remote workspaces are empty or absent, Terraform will create workspaces and update the remote state accordingly. However, if your workspace requires variables or a specific version of Terraform for remote operations, we recommend that you create your remote workspaces on HCP Terraform before running any remote operations against them.

Workspace Names

Terraform uses shortened names without the common prefix to interact with workspaces on the command line. For example, if prefix = "networking-", use terraform workspace select prod to switch to the Terraform CLI workspace prod within the current configuration. However, remote Terraform operations such as plan and apply for that Terraform CLI workspace will take place in the HCP Terraform workspace networking-prod.

Because of this, the terraform.workspace interpolation expression produces different results depending on whether a remote workspace is configured to perform operations locally or remotely. For example, in a remote workspace called networking-prod created with prefix = "networking-" the expression produces the following:

• For local operations, terraform.workspace = prod
• For remote operations, terraform.workspace= networking-prod

Prior to Terraform version 1.1.0, HCP Terraform workspaces used only the single default Terraform CLI workspace internally. So if a Terraform configuration used terraform.workspace to return dev or prod, remote runs in HCP Terraform would always evaluate it as default, regardless of which workspace you set with the terraform workspace select command. Therefore, we do not recommend using terraform.workspace in Terraform configurations that use Terraform 1.0.x or earlier and run remote operations against HCP Terraform workspaces.

Determining Run Environment

If you need to determine whether a run is local or remote in your Terraform configuration, we recommend using HCP Terraform run environment variables. The example below uses HCP_TERRAFORM_RUN_ID.

output "current_workspace_name" {
  value = terraform.workspace
}

variable "HCP_TERRAFORM_RUN_ID" {
  type    = string
  default = ""
}

output "remote_execution_determine" {
  value = "Remote run environment? %{if var.HCP_TERRAFORM_RUN_ID != ""}Yes%{else}No this is local%{endif}!"
}

Example Configurations

Basic Configuration

# Using a single workspace:
terraform {
  backend "remote" {
    hostname = "app.terraform.io"
    organization = "company"

    workspaces {
      name = "my-app-prod"
    }
  }
}

# Using multiple workspaces:
terraform {
  backend "remote" {
    hostname = "app.terraform.io"
    organization = "company"

    workspaces {
      prefix = "my-app-"
    }
  }
}

Using CLI Input

# main.tf
terraform {
  required_version = "~> 0.12.0"

  backend "remote" {}
}

Backend configuration file:

# config.remote.tfbackend
workspaces { name = "workspace" }
hostname     = "app.terraform.io"
organization = "company"

Running terraform init with the backend file:

terraform init -backend-config=config.remote.tfbackend

Data Source Configuration

data "terraform_remote_state" "foo" {
  backend = "remote"

  config = {
    organization = "company"

    workspaces = {
      name = "workspace"
    }
  }
}

Configuration Variables

The following configuration options are supported:

• hostname - (Optional) The remote backend hostname to connect to. Defaults to app.terraform.io.

• organization - (Required) The name of the organization containing the targeted workspace(s).

• token - (Optional) The token used to authenticate with the remote backend. We recommend omitting the token from the configuration, and instead using terraform login or manually configuring credentials in the CLI config file.

• workspaces - (Required) A block specifying which remote workspace(s) to use. The workspaces block supports the following keys:

  • name - (Optional) The full name of one remote workspace. When configured, only the default workspace can be used. This option conflicts with prefix.
  • prefix - (Optional) A prefix used in the names of one or more remote workspaces, all of which can be used with this configuration. The full workspace names are used in HCP Terraform, and the short names (minus the prefix) are used on the command line for Terraform CLI workspaces. If omitted, only the default workspace can be used. This option conflicts with name.

Command Line Arguments

For configurations that include a backend "remote" block, commands that make local modifications to Terraform state and then push them back up to the remote workspace accept the following option to modify that behavior:

• -ignore-remote-version - Override checking that the local and remote Terraform versions agree, making an operation proceed even when there is a mismatch.

  Normally state-modification operations require using a local version of Terraform CLI which is compatible with the Terraform version selected for the remote workspace as part of its settings. This is to avoid the local operation creating a new state snapshot which the workspace's remote execution environment would then be unable to decode.

  Overriding this check can result in an HCP Terraform workspace that is no longer able to complete remote operations, so we recommend against using this option.

Excluding Files from Upload with .terraformignore

When executing a remote plan or apply in a CLI-driven run, an archive of your configuration directory is uploaded to HCP Terraform. You can define paths to ignore from upload via a .terraformignore file at the root of your configuration directory. If this file is not present, the archive will exclude the following by default:

• .git/ directories
• .terraform/ directories (exclusive of .terraform/modules)

The .terraformignore file can include rules as one would include in a .gitignore file

• Comments (starting with #) or blank lines are ignored
• End a pattern with a forward slash / to specify a directory
• Negate a pattern by starting it with an exclamation point !

Note that unlike .gitignore, only the .terraformignore at the root of the configuration directory is considered.