---

name: terraform description: | Terraform infrastructure-as-code reference for HCL syntax, state management, module design, and provider configuration. Use when working with Terraform configurations (.tf files), running terraform commands, troubleshooting state issues, or designing modules. Includes Telmate Proxmox provider patterns. Triggers: terraform, tfstate, .tf files, HCL, modules, providers, proxmox_vm_qemu. agent: terraform-expert

Terraform Skill

Infrastructure-as-code reference for Terraform configurations, state management, and provider patterns.

Quick Reference

Copy# Core workflow
terraform init              # Initialize, download providers
terraform validate          # Syntax validation
terraform fmt -recursive    # Format HCL files
terraform plan              # Preview changes
terraform apply             # Apply changes

# Inspection
terraform state list                    # List resources in state
terraform state show <resource>         # Show resource details
terraform graph | dot -Tsvg > graph.svg # Dependency graph

# Debug
TF_LOG=DEBUG terraform plan 2>debug.log

Core Workflow

Copyinit → validate → fmt → plan → apply

1. init: Download providers, initialize backend
2. validate: Check syntax and configuration validity
3. fmt: Ensure consistent formatting
4. plan: Preview what will change (review carefully)
5. apply: Execute changes

Reference Files

Load on-demand based on task:

Validation Checklist

Before terraform apply:

• terraform init completed successfully
• terraform validate passes
• terraform fmt applied
• terraform plan reviewed (check destroy/replace operations)
• Backend configured correctly (for team environments)
• State locking enabled (if remote backend)
• Sensitive variables marked sensitive = true
• Provider versions pinned in terraform.tf
• No secrets in version control
• Blast radius assessed (what could break?)

Variable Precedence

(highest to lowest)

1. -var flag: terraform apply -var="name=value"
2. -var-file flag: terraform apply -var-file=prod.tfvars
3. *.auto.tfvars files (alphabetically)
4. terraform.tfvars file
5. TF_VAR_* environment variables
6. Variable defaults in variables.tf