Remote state data source in Terraform - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a remote state data source using Terraform.

Terraform

data "terraform_remote_state" "example" {
  backend = "[1]"
  config = {
    bucket = "my-terraform-state"
    key    = "state.tfstate"
    region = "us-west-2"
  }
}

Drag options to blanks, or click blank then click option'

As3

Blocal

Cgcs

Dazurerm

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'local' instead of a remote backend.

Confusing backend names like 'gcs' for AWS S3.

The backend specifies where the remote state is stored. For AWS S3, use s3.

2fill in blank

medium

Complete the code to access an output named 'vpc_id' from the remote state.

Terraform

output "vpc_id" {
  value = data.terraform_remote_state.example.outputs.[1]
}

Drag options to blanks, or click blank then click option'

AvpcId

Bvpc_id

CVpcId

Dvpcid

Attempts:

3 left

💡 Hint

Common Mistakes

Using camelCase or PascalCase instead of snake_case.

Misspelling the output name.

Terraform outputs are case-sensitive and usually use snake_case. The output name is 'vpc_id'.

3fill in blank

hard

Fix the error in the remote state data source configuration by completing the missing backend name.

Terraform

data "terraform_remote_state" "network" {
  backend = "[1]"
  config = {
    bucket = "network-state"
    key    = "network.tfstate"
    region = "us-east-1"
  }
}

Drag options to blanks, or click blank then click option'

Alocal

Bhttp

Cs3

Dconsul

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'local' backend for remote state.

Using unsupported backend names.

The backend must be set to a valid remote backend. For AWS S3, use s3.

4fill in blank

hard

Fill both blanks to correctly configure the remote state data source with S3 backend and specify the state file key.

Terraform

data "terraform_remote_state" "app" {
  backend = "[1]"
  config = {
    bucket = "app-state-bucket"
    key    = "[2]"
    region = "us-east-2"
  }
}

Drag options to blanks, or click blank then click option'

As3

Bapp.tfstate

Cstate.tfstate

Dlocal

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'local' as backend for remote state.

Incorrect or generic state file names.

The backend is 's3' for AWS S3 storage. The key is the path to the state file, here 'app.tfstate'.

5fill in blank

hard

Fill all three blanks to define a remote state data source with S3 backend, specify the bucket, and access the 'subnet_ids' output.

Terraform

data "terraform_remote_state" "network" {
  backend = "[1]"
  config = {
    bucket = "[2]"
    key    = "network.tfstate"
    region = "us-west-1"
  }
}

output "subnet_ids" {
  value = data.terraform_remote_state.network.outputs.[3]
}

Drag options to blanks, or click blank then click option'

As3

Bnetwork-state-bucket

Csubnet_ids

Dvpc_id

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong backend names.

Incorrect bucket names.

Accessing outputs with wrong names.

The backend is 's3' for AWS S3. The bucket is the S3 bucket name. The output accessed is 'subnet_ids'.

Practice

1.

What is the main purpose of using a terraform_remote_state data source?

easy

A. To read outputs from another Terraform state file

B. To store Terraform state remotely

C. To initialize Terraform backend configuration

D. To create new resources in a remote cloud

Solution

1. Step 1: Understand the role of terraform_remote_state

   This data source is designed to read outputs from a different Terraform state, allowing one configuration to use values from another.

2. Step 2: Differentiate from other Terraform features

   Storing state remotely or initializing backend are separate concepts; terraform_remote_state specifically reads outputs, not stores or initializes.

3. Final Answer:

   To read outputs from another Terraform state file -> Option A

4. Quick Check:

   Remote state data source = read outputs [OK]

Hint: Remote state data source reads outputs, not stores state [OK]

Common Mistakes:

• Confusing remote state data source with backend configuration
• Thinking it stores state instead of reading outputs
• Assuming it creates resources remotely

2.

Which of the following is the correct syntax to define a terraform_remote_state data source to read from an S3 backend?

data "terraform_remote_state" "example" {
  backend = "s3"
  config = {
    bucket = "my-bucket"
    key    = "path/to/terraform.tfstate"
    region = "us-west-2"
  }
}

easy

A. data "terraform_remote_state" "example" { backend = "local" config = { path = "my-bucket/path/to/terraform.tfstate" } }

B. resource "terraform_remote_state" "example" { backend = "s3" config = { bucket = "my-bucket" key = "path/to/terraform.tfstate" region = "us-west-2" } }

C. data "terraform_remote_state" "example" { backend = "s3" config = { bucket = "my-bucket" key = "path/to/terraform.tfstate" region = "us-west-2" } }

D. data "terraform_state" "example" { backend = "s3" config = { bucket = "my-bucket" key = "path/to/terraform.tfstate" region = "us-west-2" } }

Solution

1. Step 1: Identify correct resource type and backend

   The data source must be declared with data "terraform_remote_state" and backend set to "s3" for S3 remote state.

2. Step 2: Check config block correctness

   The config block must include bucket, key, and region keys correctly for S3 backend.

3. Final Answer:

   Correct syntax uses data source with backend "s3" and proper config -> Option C

4. Quick Check:

   Correct syntax = data + backend s3 + config keys [OK]

Hint: Use data "terraform_remote_state" with backend and config keys [OK]

Common Mistakes:

• Using resource instead of data block
• Wrong backend name like "local" instead of "s3"
• Misspelling data source name as "terraform_state"

3.

Given this Terraform code snippet, what will be the output of output "vpc_id"?

data "terraform_remote_state" "network" {
  backend = "local"
  config = {
    path = "../network/terraform.tfstate"
  }
}

output "vpc_id" {
  value = data.terraform_remote_state.network.outputs.vpc_id
}

medium

A. The VPC ID value from the remote state output named "vpc_id"

B. An error because local backend cannot be used with remote state data source

C. Null because outputs are not accessible from remote state

D. The entire remote state file content as a string

Solution

1. Step 1: Understand remote state data source with local backend

   The local backend can be used to read a remote state file stored locally, so the data source reads outputs from that file.

2. Step 2: Access the specific output value

   The output block references data.terraform_remote_state.network.outputs.vpc_id, which fetches the "vpc_id" output from the remote state.

3. Final Answer:

   The VPC ID value from the remote state output named "vpc_id" -> Option A

4. Quick Check:

   Remote state outputs accessible = VPC ID value [OK]

Hint: Remote state outputs accessed via data.terraform_remote_state.outputs [OK]

Common Mistakes:

• Assuming local backend is invalid for remote state data source
• Expecting entire state file instead of specific output
• Thinking outputs are inaccessible from remote state

4.

What is the likely cause of this error when using terraform_remote_state?

Error: Failed to read remote state

  on main.tf line 5, in data "terraform_remote_state" "example":
   5: data "terraform_remote_state" "example" {

Could not find state file at configured path

Given this snippet:

data "terraform_remote_state" "example" {
  backend = "local"
  config = {
    path = "../nonexistent/terraform.tfstate"
  }
}

medium

A. The backend "local" is not supported for remote state data source

B. The path to the remote state file is incorrect or file does not exist

C. Terraform version is outdated and cannot read remote state

D. The remote state file is corrupted and unreadable

Solution

1. Step 1: Analyze the error message

   The error says it could not find the state file at the configured path, indicating a missing or wrong file path.

2. Step 2: Check the config path in the data source

   The path is set to "../nonexistent/terraform.tfstate" which likely does not exist or is mistyped.

3. Final Answer:

   The path to the remote state file is incorrect or file does not exist -> Option B

4. Quick Check:

   Missing or wrong path causes file not found error [OK]

Hint: Check file path carefully for remote state data source [OK]

Common Mistakes:

• Assuming backend "local" is unsupported
• Blaming Terraform version without checking path
• Ignoring file existence and permissions

5.

You have two Terraform projects: network creates a VPC and outputs vpc_id. app needs to use that vpc_id. How should you configure app to safely get vpc_id using remote state?

// In app/main.tf

data "terraform_remote_state" "network" {
  backend = "s3"
  config = {
    bucket = "my-terraform-states"
    key    = "network/terraform.tfstate"
    region = "us-east-1"
  }
}

resource "aws_instance" "app_server" {
  subnet_id = data.terraform_remote_state.network.outputs.vpc_id
  # other config
}

What is the best practice to ensure this setup works correctly?

hard

A. Use local backend in app to avoid remote state complexity

B. Run Terraform apply in app before network to create the state file

C. Copy the VPC ID manually into app variables instead of using remote state

D. Ensure the S3 bucket and key exist and the app project has read access to the state file

Solution

1. Step 1: Verify remote state backend accessibility

   The S3 bucket and key must exist with the network project's state file, and app must have permission to read it.

2. Step 2: Understand dependency order and security

   Network must be applied first to create the state file. Using remote state avoids manual copying and keeps data consistent.

3. Final Answer:

   Ensure the S3 bucket and key exist and the app project has read access to the state file -> Option D

4. Quick Check:

   Remote state requires accessible backend and permissions [OK]

Hint: Check backend existence and permissions before using remote state [OK]

Common Mistakes:

• Running app before network causing missing state file
• Manually copying outputs causing drift
• Using local backend ignoring remote state benefits