Terraform

The terraform resource allows you to provision infrastructure using Terraform configurations within your lab environment. It executes Terraform commands in a containerized environment and can pass variables and capture outputs for use by other resources.

Use Cases

As a lab author, you can use terraform resources to:

• Lab Environment Setup: Provision cloud infrastructure required for your lab scenarios using Terraform configurations
• Real Infrastructure Integration: Connect your lab to actual cloud resources when simulated environments aren’t sufficient
• Dynamic Configuration: Generate configuration files for other lab resources based on Terraform-provisioned infrastructure

Terraform resources allow lab authors to integrate real cloud infrastructure provisioning into their lab setup workflows.

HCL Syntax

Basic Syntax

resource "terraform" "example" {
  source = "./terraform"
}

Full Syntax

resource "terraform" "example" {
  source           = "./terraform"
  version          = "1.9.8"
  working_directory = "/terraform"

  # Environment variables
  environment = {
    AWS_REGION = "us-east-1"
    TF_LOG     = "INFO"
  }

  # Terraform variables
  variables = {
    instance_count = 2
    vpc_cidr       = "10.0.0.0/16"
  }

  # Network configuration
  network {
    id = resource.network.main.meta.id
    ip_address = "10.0.0.5"
    aliases = ["terraform"]
  }

  # Volume mounts
  volume {
    source      = "./terraform-modules"
    destination = "/modules"
    type        = "bind"
    read_only   = true
  }
}

Fields

Field	Required	Type	Description
source	✓	string	Source directory containing Terraform configuration files
version		string	Version of Terraform to use. Defaults to “1.9.8”.
working_directory		string	Working directory to run terraform commands. Defaults to ”./“.
environment		map(string)	Environment variables to set when running Terraform. Defaults to empty map.
variables		any	Variables to pass to Terraform
network		block	Network attachments (repeatable)
volume		block	Volume mounts (repeatable)

Network Block

terraform → network

Network configuration for the Terraform container (repeatable).

Field	Required	Type	Description
id	✓	reference to network	Reference to network resource
ip_address		string	Static IP address. Auto-assigned if not specified.
aliases		list(string)	Network aliases. Defaults to empty list.

Volume Block

terraform → volume

Volume mount configuration for the Terraform container (repeatable).

Field	Required	Type	Description
source	✓	string	Source path or volume name
destination	✓	string	Mount path inside container
type		string	Volume type: “bind”, “volume”, or “tmpfs”. Defaults to “bind”.
read_only		bool	Mount as read-only. Defaults to false.
bind_propagation		string	Bind propagation mode: “shared”, “private”, “slave”, “rslave”, “rprivate”
bind_propagation_non_recursive		bool	Use non-recursive bind mounting. Defaults to false.
selinux_relabel		string	SELinux relabeling mode: “shared” or “private”

Computed Attributes

These attributes are set by the system after Terraform execution:

Field	Type	Description
output	any	Terraform outputs defined in the configuration
apply_output	string	Console output from the terraform apply command
source_checksum	string	Checksum of the source directory

Validation Rules

• Source directory must exist and contain valid Terraform configuration files
• Working directory paths are normalized and made relative to container root
• Volume source paths are made absolute relative to config file location
• Terraform version must be a valid version string
• Network and volume configurations follow container resource validation rules

Examples

Basic Terraform Configuration

resource "terraform" "aws_vpc" {
  source = "./infrastructure"

  variables = {
    region = "us-west-2"
    environment = "lab"
  }
}

Advanced Configuration with Custom Version

resource "terraform" "kubernetes" {
  source  = "./k8s-terraform"
  version = "1.8.0"

  environment = {
    KUBE_CONFIG_PATH = "/root/.kube/config"
  }

  variables = {
    cluster_name = "lab-cluster"
    node_count   = 3
  }

  volume {
    source      = "./kubeconfig"
    destination = "/root/.kube"
    type        = "bind"
  }
}

Using Terraform Outputs in Other Resources

resource "terraform" "infrastructure" {
  source = "./terraform"

  variables = {
    vpc_cidr = "10.0.0.0/16"
  }
}

## Reference Terraform outputs
resource "container" "app" {
  image {
    name = "myapp:latest"
  }

  environment = {
    VPC_ID = resource.terraform.infrastructure.output.vpc_id
  }
}

Best Practices

1. State Management: Use remote state backends for production-like scenarios
2. Version Pinning: Specify exact Terraform versions for consistency across environments
3. Variable Organization: Use structured variable files and clear naming conventions
4. Output Usage: Define meaningful outputs for integration with other lab resources
5. Resource Tagging: Include proper tags for cost tracking and resource management
6. Network Isolation: Use dedicated networks for multi-tier application demonstrations
7. Volume Mounts: Mount configuration files and modules as read-only when possible
8. Environment Variables: Use environment variables for sensitive configuration like API keys