How to fix Error: rpc error: code = Unavailable in Terraform

Verify that your provider versions are compatible with your Terraform version. Upgrade to the latest provider versions as many RPC errors are fixed in newer releases.

terraform version

Update providers in your Terraform configuration:

terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = ">= 5.0"  # Use latest stable version
    }
  }
}

Then run:

terraform init -upgrade

Terraform debug logs often reveal the underlying panic or error in the provider. Set the TF_LOG environment variable before running your command:

export TF_LOG=DEBUG
terraform plan > terraform_debug.log 2>&1

After running the command, examine the log file for panic stack traces or specific error messages that indicate what the provider is failing on. Look for lines containing "panic:" to find the exact issue.

grep -i "panic:" terraform_debug.log

Invalid or null values in your configuration can trigger provider crashes. Ensure all required resource attributes have valid values. Check for:

- Variables that might be null or undefined
- Missing required provider arguments
- Invalid data types or malformed values

terraform validate

Review your variables file and confirm all required values are set:

# Ensure required variables are defined and not null
variable "vpc_id" {
  type = string
  validation {
    condition     = can(regex("^vpc-", var.vpc_id))
    error_message = "VPC ID must be a valid AWS VPC ID."
  }
}

If multiple resources are causing issues, use the -target flag to run Terraform against specific resources. This helps identify which resource is triggering the provider crash:

terraform plan -target='aws_instance.example'
terraform apply -target='aws_instance.example'

Once you identify the problematic resource, examine its configuration carefully for invalid values or unsupported combinations.

Sometimes a corrupted state file can cause provider communication issues. Back up your state and reinitialize:

# Backup current state
cp terraform.tfstate terraform.tfstate.backup

# Remove lock file if it exists
rm .terraform.lock.hcl

# Reinitialize
terraform init

Verify the state is valid:

terraform state list
terraform state show <resource>

If after upgrading providers and validating your configuration the error persists, it likely indicates a provider bug. Collect diagnostic information and report it to the provider's GitHub repository:

1. Save the debug log output from step 2
2. Note your Terraform and provider versions
3. Provide a minimal configuration that reproduces the issue
4. Open an issue on the provider's GitHub repository (e.g., https://github.com/hashicorp/terraform-provider-aws/issues)

Include the panic message from your debug logs, as this helps maintainers identify and fix the underlying bug.