11. State

terraform state

Core Idea

State is Terraform’s snapshot of your cloud resources at a point in time: it maps config to real infrastructure, and the CLI commands are how you read and work with it.

• What state is: the recorded condition of resources at a specific time.
• How Terraform preserves state.
• The Terraform CLI commands that operate on it.

What is State?

**A particular condition of cloud resources at a specific time.**

eg. We expect there to be a Virtual Machine running CentOS on AWS with a compute type of t2.micro.

How does Terraform preserve state?

When you provision infrastructure via Terraform it will create a state file named terraform.tfstate.
This state file is a JSON data structure with a one-to-one mapping from resource instances to remote objects

Configuration files:

• main.tf
• variables.tf
• terraform.tfvars

Terraform apply command
Terraform API
Remote objects
State file
terraform.tfstate

---

Terraform CLI commands

• terraform state list List resources in the state
• terraform state mv Move an item in the state
• terraform state pull Pull current remote state and output to stdout
• terraform state push Update remote state from a local state
• terraform state replace-provider Replace provider in the state
• terraform state rm Remove instances from the state
• terraform state show Show a resource in the state