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¶