Companion to Terraform cheat sheet and the Terraform series.
Application Default Credentials (ADC)
Credential chain the Google provider uses, often from gcloud auth application-default login or a service account. See Infrastructure as Code with Terraform.
Apply
Execute a plan to create, update, or destroy resources. See Infrastructure as Code with Terraform.
Backend
Where Terraform stores state (local file or remote such as GCS). See State data in Terraform.
Data source
Read-only provider lookup; not destroyed by Terraform. See HCL structure in Terraform.
Declarative
Describe desired end state; the tool reconciles infrastructure. See Infrastructure as Code with Terraform.
Drift
Live infrastructure differing from configuration and state. See State data in Terraform.
HCL
HashiCorp Configuration Language; default syntax for .tf files. See HCL structure in Terraform.
Import
Bring an existing cloud resource under Terraform management. See State data in Terraform.
Infrastructure as Code (IaC)
Define infrastructure in version-controlled files instead of manual console work. See Infrastructure as Code with Terraform.
Lock file (.terraform.lock.hcl)
Pins provider versions and checksums after init. See Infrastructure as Code with Terraform.
Meta-argument
Resource argument that changes behavior (count, for_each, lifecycle, etc.). See HCL structure in Terraform.
Module
Reusable bundle of Terraform configuration with inputs and outputs. See Terraform modules.
OpenTofu
Open-source Terraform-compatible engine and CLI fork. See Terraform vs OpenTofu and alternatives.
Output
Value exported after apply. See HCL structure in Terraform.
Plan
Preview of changes Terraform will make. See Infrastructure as Code with Terraform.
Provider
Plugin that implements resource types for a cloud or service. See Infrastructure as Code with Terraform.
Refresh
Update state from provider APIs before planning. See State data in Terraform.
Remote state
Reading another stack’s state outputs via terraform_remote_state. See State data in Terraform.
Resource
Managed infrastructure object create/update/destroy lifecycle. See HCL structure in Terraform.
Root module
Configuration directory where you run apply. See Terraform modules.
State
Mapping from configuration addresses to real resource IDs and attributes. See State data in Terraform.
Variable
Input parameter for a module or root configuration. See HCL structure in Terraform.
Workspace
Named state instance within one backend configuration. See State data in Terraform.
terraform fmt
Built-in formatter for canonical HCL style. See Formatting and validating Terraform files.
terraform validate
Static check of configuration syntax and consistency. See Formatting and validating Terraform files.