Terraform Commands

This section provides a comprehensive reference for Terraform commands, including common use cases and best practices.

Basic Commands

Initialization and Planning

# Initialize Terraform working directory
terraform init

# Format Terraform files
terraform fmt

# Validate Terraform files
terraform validate

# Show execution plan
terraform plan

# Show execution plan with output file
terraform plan -out=tfplan

Resource Management

# Apply changes
terraform apply

# Apply changes from plan file
terraform apply tfplan

# Destroy infrastructure
terraform destroy

# Show current state
terraform show

# List resources
terraform state list

Common Use Cases

Working with State

# Move resource in state
terraform state mv SOURCE_ADDRESS DESTINATION_ADDRESS

# Remove resource from state
terraform state rm ADDRESS

# Import existing resource
terraform import ADDRESS ID

Working with Variables

# Set variable value
terraform apply -var="instance_type=t2.micro"

# Set variable file
terraform apply -var-file="prod.tfvars"

# Override variable
terraform apply -var="region=us-west-2" -var="environment=staging"

Output Management

# Show outputs
terraform output

# Show specific output
terraform output instance_ip

# Show outputs in JSON format
terraform output -json

Best Practices

  1. State Management: Use remote state storage 
    terraform {
  backend "s3" {
    bucket = "my-terraform-state"
    key    = "prod/terraform.tfstate"
    region = "us-west-2"
  }
}
  2. Variable Organization: Use separate variable files 
    # variables.tf
variable "environment" {
  description = "Environment name"
  type        = string
}

# prod.tfvars
environment = "production"
  3. Module Usage: Organize code into modules 
    module "vpc" {
  source = "./modules/vpc"
     
  environment = var.environment
  cidr_block  = var.vpc_cidr
}

Troubleshooting

Common Issues

  1. State Lock Issues 
    # Force unlock state
terraform force-unlock LOCK_ID
  2. Provider Issues 
    # Reinitialize with specific provider
terraform init -upgrade -plugin-dir=/path/to/provider
  3. Resource Dependencies 
    # Show dependency graph
terraform graph

Additional Resources