2 terraform.tfstate

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✊ State File (terraform.tfstate)

→ Terraform’s memory
→ Stores unique ID for each resource, attributes
👉 State = Terraform’s source of truth. (Never Delete)

Must be:

• Protected
• Not edited manually
• Stored remotely (S3 + DynamoDB lock recommended)

⭐ State File Lifecycle

Every Terraform command uses the state file:

• terraform init
  → initializes backend
  → downloads providers
  → prepares state handling (no lock)

• terraform plan
  → reads current tfstate
  → reads real infra (AWS)
  → shows diff only (no change, no lock)

• terraform apply
  → acquires state lock (.terraform.tfstate.lock.info) → reads current state
  → updates real infra
  → writes updated state
  → releases lock

• terraform destroy
  → acquires state lock
  → deletes real infra
  → updates state
  → releases lock

• terraform refresh (implicit)
  → syncs state with real infra
  → no changes applied

⭐ Useful Terraform State Commands

Syntax:

terraform state <subcommand> [options] [args]

Command	Use
terraform state list	Shows all managed resources
terraform state show <resourceType.resourceName>	Shows details of a resource from state
terraform state pull	Downloads and prints remote state
terraform state rm <resourceType.resourceName>	Removes resource from state (unmanaged)
terraform state mv <resourceType.resourceName1> <resourceType.resourceName2>	Renames or moves a resource in state

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☁️ Remote Backend – TF State

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⭐ Remote Backend (S3)

Remote backend stores state in AWS S3 instead of local.

Benefits:

• ✔ Secure, centralized storage
• ✔ Versioning & backups
• ✔ Team collaboration
• ✔ Locking → Prevents two people running Terraform at the same time.

Backend block: Backend bucket must always exist before Terraform runs.

terraform {
  backend "s3" {
    bucket         = "my-tf-state"
    key            = "dev/terraform.tfstate"
    region         = "us-east-1"
    encrypt        = true
    use_lockfile   = true
  }
}

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⭐ Remote State File Structure (S3)

Example S3 folder:

my-tf-state/
  dev/terraform.tfstate
  test/terraform.tfstate
  prod/terraform.tfstate

Use separate state for:
✔ dev
✔ test
✔ prod

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