The concept

Resource Tracking

• A way for Terraform to keep tabs on what has been deployed

• Critical to terraform functionality

Terraform State

• Simply put, it maps real-world resources to Terraform configuration

• Stored in flat files, by default name "terraform.tfstate"

• Help terraform calculate deployment data and create new deployment plan

• Prior to any modification operation, Terraform refresh the state file.

• Resource dependency metadata is also tracked in the state file

• Help boost deployment performance by caching resource attributes if subsequent use

• Never lose the Terraform state file!

Terraform State Command

• Terraform state command is a utility for manipulating and reading the Terraform state file.

• Scenario:

  • Advance state management

  • Manually remove a resource from Terraform state file so that it's not managed by Terraform

  • Listing out tracked resources and their detail (via state and list subcommands)