Terraform Plan Command

Generate an execution plan showing what Terraform will do.

Usage

/tf-plan                          # Basic plan
/tf-plan prod.tfvars             # With var file
/tf-plan -target=module.vpc      # Target specific resource
/tf-plan -out=tfplan             # Save plan to file

What This Command Does

1. Refreshes state (unless -refresh=false)
2. Compares desired state with actual state
3. Generates execution plan
4. Shows what will be created, changed, or destroyed
5. Optionally saves plan to file

Execution Steps

Step 1: Pre-Flight Checks

# Verify initialization
terraform validate

# Check formatting
terraform fmt -check

Step 2: Run Plan

# Basic plan
terraform plan

# With var file
terraform plan -var-file="${ARGS}"

# With target
terraform plan -target="${TARGET}"

# Save plan
terraform plan -out=tfplan

# CI/CD optimized
terraform plan -no-color -out=tfplan -detailed-exitcode

Step 3: Review Output

Plan output shows:

• + Resources to create
• - Resources to destroy
• ~ Resources to modify
• +/- Resources to replace

Common Options

Option	Description
-var-file=FILE	Load variables from file
-var='KEY=VALUE'	Set individual variable
-target=RESOURCE	Plan specific resource
-out=FILE	Save plan to file
-refresh=false	Skip state refresh
-detailed-exitcode	Return 2 if changes
-no-color	Disable colored output
-parallelism=N	Limit parallel operations

Exit Codes (with -detailed-exitcode)

Code	Meaning
0	No changes
1	Error
2	Changes detected

Examples

Basic Plan

terraform plan

Plan with Variables

terraform plan -var-file="environments/prod.tfvars"

Plan Specific Resource

terraform plan -target=aws_instance.web
terraform plan -target=module.networking

CI/CD Plan

terraform plan \
  -no-color \
  -out=tfplan \
  -detailed-exitcode \
  -var-file="prod.tfvars"

Best Practices

1. Always review plan before apply
2. Save plan to file in CI/CD
3. Use -detailed-exitcode for automation
4. Target cautiously (may miss dependencies)