Terraform Remote State Storage Demo with Project-1 and Project-2¶

Step-01: Introduction¶

Understand Terraform Remote State Storage
Terraform Remote State Storage Demo with two projects

Step-02: Copy Project 1 VPC from Section 19¶

Copy project-1-aws-vpc from 19-Remote-State-Storage-with-AWS-S3-and-DynamoDB

Step-03: Copy Project 2 App1 with ASG and ALB from Section 15¶

Copy terraform-manifests\* all files from Section 15-Autoscaling-with-Launch-Templates and copy to project-2-app1-with-asg-and-alb

Remove the following 4 files related to VPC from Project-2 project-2-app1-with-asg-and-alb
c4-01-vpc-variables.tf
c4-02-vpc-module.tf
c4-03-vpc-outputs.tf
vpc.auto.tfvars

Step-05: Project-2: c0-terraform-remote-state-datasource.tf¶

Create terraform_remote_state Datasource

In this datasource, we will provide the Terraform State file information of our Project-1-AWS-VPC

# Terraform Remote State Datasource
data "terraform_remote_state" "vpc" {
  backend = "s3"
  config = {
    bucket = "terraform-on-aws-for-ec2"
    key    = "dev/project1-vpc/terraform.tfstate"
    region = "us-east-1"
  }
}

Step-06: Project-2: Update Security Groups VPC ID¶

c5-03-securitygroup-bastionsg.tf
c5-04-securitygroup-privatesg.tf

c5-05-securitygroup-loadbalancersg.tf

# Before
  vpc_id      = module.vpc.vpc_id
# After
  vpc_id      = data.terraform_remote_state.vpc.outputs.vpc_id

Step-07: Project-2: Update Bastion EC2 Instance VPC Subnet ID¶

c7-03-ec2instance-bastion.tf

# Before
  subnet_id = module.vpc.public_subnets[0]
# After
  subnet_id = data.terraform_remote_state.vpc.outputs.public_subnets[0]

Step-08: Project-2: c8-elasticip.tf¶

# Before
  depends_on = [ module.ec2_public, module.vpc ]
# After
  depends_on = [ module.ec2_public, /*module.vpc*/ ]

Step-09: Project-2: c10-02-ALB-application-loadbalancer.tf¶

# Before
  vpc_id = module.vpc.vpc_id
  subnets = module.vpc.public_subnets
# After
  vpc_id = data.terraform_remote_state.vpc.outputs.vpc_id 
  subnets = data.terraform_remote_state.vpc.outputs.public_subnets

Step-10: Project-2: c12-route53-dnsregistration.tf¶

# Add DNS name relevant to demo
  name    = "tf-multi-app-projects.devopsincloud.com"

Step-11: Project-2: Create S3 Bucket and DynamoDB Table for Remote State Storage¶

Create S3 Bucket and DynamoDB Table for Remote State Storage
Leverage Same S3 bucket terraform-on-aws-for-ec2 with different folder for project-2 state file dev/project2-app1/terraform.tfstate
Also create a new DynamoDB Table for project-2
Create Dynamo DB Table
Table Name: dev-project2-app1
Partition key (Primary Key): LockID (Type as String)
Table settings: Use default settings (checked)
Click on Create

Step-12: Project-2: c1-versions.tf¶

Update c1-versions.tf with Remote State Backend

  # Adding Backend as S3 for Remote State Storage
  backend "s3" {
    bucket = "terraform-on-aws-for-ec2"
    key    = "dev/project2-app1/terraform.tfstate"
    region = "us-east-1" 

    # Enable during Step-09     
    # For State Locking
    dynamodb_table = "dev-project2-app1"    
  }

Step-13: c13-03-autoscaling-resource.tf¶

# Before
  vpc_zone_identifier = module.vpc.private_subnets

# After
  vpc_zone_identifier = data.terraform_remote_state.vpc.outputs.private_subnets

Step-14: Project-1: Execute Terraform Commands¶

Create Project-1 Resources (VPC)

# Terraform Initialize
terraform init

# Terraform Validate
terraform validate

# Terraform Plan
terraform plan

# Terraform Apply
terraform apply -auto-approve

# Terraform State List
terraform state list

# Observations
1. Verify VPC Resources created
2. Verify S3 bucket and terraform.tfstate file for project-1

Step-15: Project-2: Execute Terraform Commands¶

Create Project-2 Resources (VPC)

# Terraform Initialize
terraform init

# Terraform Validate
terraform validate

# Terraform Plan
terraform plan

# Terraform Apply
terraform apply -auto-approve

# Terraform State List
terraform state list

Step-16: Verify Project-2 Resources¶

Verify S3 bucket and terraform.tfstate file for project-2
Verify Security Groups
Verify EC2 Instances (Bastion Host and ASG related EC2 Instances)
Verify Application Load Balancer and Target Group
Verify Autoscaling Group and Launch template

Access Application and Test

# Access Application
https://tf-multi-app-projects1.devopsincloud.com
https://tf-multi-app-projects1.devopsincloud.com/app1/index.html
https://tf-multi-app-projects1.devopsincloud.com/app1/metadata.html

Step-17: Project-2 Clean-Up¶

# Change Directory 
cd project-2-app1-with-asg-and-alb
# Terraform Destroy
terraform destroy -auto-approve

# Delete files
rm -rf .terraform*

Step-18: Project-1 Clean-Up¶

# Change Directory
cd project-1-aws-vpc

# Terraform Destroy
terraform destroy -auto-approve

# Delete files
rm -rf .terraform*