Terraform Validation
Validate Terraform code syntax and configuration before deployment to catch errors early and prevent failed deployments.
What is Validation?
Terraform validation checks:
- Syntax Errors: Invalid HCL syntax, missing braces, typos
- Argument Errors: Invalid resource arguments or blocks
- Type Errors: Wrong data types for variables
- Reference Errors: References to non-existent resources or variables
- Provider Configuration: Valid provider blocks and credentials
Validation does NOT check:
- Whether resources will successfully create (requires plan)
- Cloud provider API limits or quotas
- Resource naming conflicts in your cloud account
- Cost implications
Automatic Validation
ops0 automatically validates Terraform code:
On File Save
Validation runs in background when you save files in the editor.
Before Deployment
Deployment blocked if validation fails (gating requirement).
Results Display
Errors shown inline in editor and in validation panel.
Manual Validation
Trigger validation manually:
Open Project
Navigate to your IaC project.
Click Validate
Find the Validate button in project toolbar.
Review Results
Validation output appears showing pass/fail status.
Success Output:
✓ Terraform Validation Passed
Checked 12 files in 2.3 seconds
No issues found
Files validated:
✓ main.tf
✓ variables.tf
✓ outputs.tf
✓ modules/vpc/main.tf
✓ modules/vpc/variables.tf
...
Failure Output:
✗ Terraform Validation Failed
Found 3 errors in 2 files
main.tf:
Line 15: Unsupported argument "instance_types" on resource "aws_instance"
Line 23: Missing required argument "ami"
modules/database/main.tf:
Line 8: Invalid reference: var.databse_name (did you mean var.database_name?)
Run validation again after fixing errors.
Validation Error Types
Syntax Errors
Example Error:
Error: Invalid block definition
main.tf:15:1
Missing closing brace for resource block starting at line 10.
Fix:
resource "aws_instance" "web" {
ami = "ami-0c55b159cbfafe1f0"
instance_type = "t3.medium"
} # Add missing brace
Argument Errors
Example Error:
Error: Unsupported argument
main.tf:12:3
An argument named "instance_types" is not expected here.
Did you mean "instance_type"?
Fix:
resource "aws_instance" "web" {
ami = "ami-0c55b159cbfafe1f0"
instance_type = "t3.medium" # Singular, not plural
}
Required Argument Missing
Example Error:
Error: Missing required argument
main.tf:10:1
The argument "ami" is required, but no definition was found.
Fix:
resource "aws_instance" "web" {
ami = "ami-0c55b159cbfafe1f0" # Add required argument
instance_type = "t3.medium"
}
Invalid Reference
Example Error:
Error: Reference to undeclared resource
main.tf:25:15
There is no resource "aws_vpc" "main" declared in the configuration.
Fix: Either add the missing resource or correct the reference:
# Option 1: Add the resource
resource "aws_vpc" "main" {
cidr_block = "10.0.0.0/16"
}
# Option 2: Fix the reference
subnet_id = aws_subnet.public.id # Use correct resource
Re-Validating After Fixes
After fixing validation errors:
Save Changes
Update Terraform files with fixes.
Run Validation
Click Validate to verify syntax errors fixed.
Continue to Deployment
Once validation passes, proceed with deployment.