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Terraform Remote State Storage & Locking

Step-01: Introduction

  • Understand Terraform Backends
  • Understand about Remote State Storage and its advantages
  • This state is stored by default in a local file named "terraform.tfstate", but it can also be stored remotely, which works better in a team environment.
  • Create AWS S3 bucket to store terraform.tfstate file and enable backend configurations in terraform settings block
  • Understand about State Locking and its advantages
  • Create DynamoDB Table and implement State Locking by enabling the same in Terraform backend configuration

Step-02: Create S3 Bucket

  • Go to Services -> S3 -> Create Bucket
  • Bucket name: terraform-stacksimplify
  • Region: US-East (N.Virginia)
  • Bucket settings for Block Public Access: leave to defaults
  • Bucket Versioning: Enable
  • Rest all leave to defaults
  • Click on Create Bucket
  • Create Folder
  • Folder Name: dev
  • Click on Create Folder

Step-03: Terraform Backend Configuration

  • Reference Sub-folder: terraform-manifests
  • Terraform Backend as S3
  • Add the below listed Terraform backend block in Terrafrom Settings block in main.tf
# Terraform Backend Block
  backend "s3" {
    bucket = "terraform-stacksimplify"
    key    = "dev/terraform.tfstate"
    region = "us-east-1"    
  }

Step-04: Test with Remote State Storage Backend

# Initialize Terraform
terraform init

Observation: 
Successfully configured the backend "s3"! Terraform will automatically
use this backend unless the backend configuration changes.

# Verify S3 Bucket for terraform.tfstate file
bucket-name/dev/terraform.tfstate

# Validate Terraform configuration files
terraform validate

# Verify S3 Bucket for terraform.tfstate file
bucket-name/dev/terraform.tfstate

# Format Terraform configuration files
terraform fmt

# Verify S3 Bucket for terraform.tfstate file
bucket-name/dev/terraform.tfstate

# Review the terraform plan
terraform plan 

# Verify S3 Bucket for terraform.tfstate file
bucket-name/dev/terraform.tfstate

# Create Resources 
terraform apply -auto-approve

# Verify S3 Bucket for terraform.tfstate file
bucket-name/dev/terraform.tfstate
Observation: Finally at this point you should see the terraform.tfstate file in s3 bucket

# Access Application
http://<Public-DNS>

Step-05: Bucket Versioning - Test

  • Update in c2-variables.tf 
variable "instance_type" {
  description = "EC2 Instance Type - Instance Sizing"
  type = string
  #default = "t2.micro"
  default = "t2.small"
}
  • Execute Terraform Commands
# Review the terraform plan
terraform plan 

# Create Resources 
terraform apply -auto-approve

# Verify S3 Bucket for terraform.tfstate file
bucket-name/dev/terraform.tfstate
Observation: New version of terraform.tfstate file will be created

Step-06: Destroy Resources

  • Destroy Resources and Verify Bucket Versioning
# Destroy Resources
terraform destroy -auto-approve

Step-07: Terraform State Locking Introduction

  • Understand about Terraform State Locking Advantages

Step-08: Add State Locking Feature using DynamoDB Table

  • Create Dynamo DB Table
  • Table Name: terraform-dev-state-table
  • Partition key (Primary Key): LockID (Type as String)
  • Table settings: Use default settings (checked)
  • Click on Create

Step-09: Update DynamoDB Table entry in backend in c1-versions.tf

  • Enable State Locking in c1-versions.tf
  # Adding Backend as S3 for Remote State Storage with State Locking
  backend "s3" {
    bucket = "terraform-stacksimplify"
    key    = "dev2/terraform.tfstate"
    region = "us-east-1"  

    # For State Locking
    dynamodb_table = "terraform-dev-state-table"
  }

Step-10: Execute Terraform Commands

# Initialize Terraform 
terraform init

# Review the terraform plan
terraform plan 
Observation: 
1) Below messages displayed at start and end of command
Acquiring state lock. This may take a few moments...
Releasing state lock. This may take a few moments...
2) Verify DynamoDB Table -> Items tab

# Create Resources 
terraform apply -auto-approve

# Verify S3 Bucket for terraform.tfstate file
bucket-name/dev2/terraform.tfstate
Observation: New version of terraform.tfstate file will be created in dev2 folder

Step-11: Destroy Resources

  • Destroy Resources and Verify Bucket Versioning
# Destroy Resources
terraform destroy -auto-approve

# Clean-Up Files
rm -rf .terraform*
rm -rf terraform.tfstate*  # This step not needed as e are using remote state storage here

References