Compute State

Next we'll move onto our Compute state. For us, this means managing our two EC2 instances.

Since we don't have a way to access the VPC output directly via the module syntax (module.vpc.vpc_id, for example), we need a way to get that data.

Luckily we can use data sources for that!

We'll use data sources for:

1. aws_vpc
2. aws_subnet_ids
3. aws_security_groups

File production/compute/main.tf

Just like before, we copy the cloudcasts.tf file, rename it main.tf, and remove any excess items. In this case, it's removing the VPC module usage.

Then we make adjustments to get the needed data so we can create our EC2 servers within the VPC that we created in the last video.

  1terraform {
  2  required_providers {
  3    aws = {
  4      source  = "hashicorp/aws"
  5      version = "3.25.0"
  6    }
  7  }
  8 
  9  backend "s3" {
 10    profile = "cloudcasts"
 11    region  = "us-east-2"
 12  }
 13}
 14 
 15provider "aws" {
 16  profile = "cloudcasts"
 17  region  = "us-east-2"
 18}
 19 
 20variable "infra_env" {
 21  type        = string
 22  description = "infrastructure environment"
 23  default     = "production"
 24}
 25 
 26variable default_region {
 27  type = string
 28  description = "the region this infrastructure is in"
 29  default = "us-east-2"
 30}
 31 
 32 
 33data "aws_ami" "app" {
 34  most_recent = true
 35 
 36  filter {
 37    name   = "state"
 38    values = ["available"]
 39  }
 40 
 41  filter {
 42    name   = "tag:Component"
 43    values = ["app"]
 44  }
 45 
 46  filter {
 47    name   = "tag:Project"
 48    values = ["cloudcast"]
 49  }
 50 
 51  filter {
 52    name   = "tag:Environment"
 53    values = ["staging"]
 54  }
 55 
 56  owners = ["self"]
 57}
 58 
 59# New data sources used:
 60data "aws_vpc" "vpc" {
 61  tags = {
 62    Name        = "cloudcasts-${var.infra_env}-vpc"
 63    Project     = "cloudcasts.io"
 64    Environment = var.infra_env
 65    ManagedBy   = "terraform"
 66  }
 67}
 68 
 69data "aws_subnet_ids" "public_subnets" {
 70  vpc_id = data.aws_vpc.vpc.id
 71 
 72  tags = {
 73    Name        = "cloudcasts-${var.infra_env}-vpc"
 74    Project     = "cloudcasts.io"
 75    Environment = var.infra_env
 76    ManagedBy   = "terraform"
 77    Role        = "public"
 78  }
 79}
 80 
 81data "aws_subnet_ids" "private_subnets" {
 82  vpc_id = data.aws_vpc.vpc.id
 83 
 84  tags = {
 85    Name        = "cloudcasts-${var.infra_env}-vpc"
 86    Project     = "cloudcasts.io"
 87    Environment = var.infra_env
 88    ManagedBy   = "terraform"
 89    Role        = "private"
 90  }
 91}
 92 
 93data "aws_security_groups" "public_sg" {
 94  tags = {
 95    Name        = "cloudcasts-${var.infra_env}-public-sg"
 96    Role        = "public"
 97    Project     = "cloudcasts.io"
 98    Environment = var.infra_env
 99    ManagedBy   = "terraform"
100  }
101}
102 
103data "aws_security_groups" "private_sg" {
104  tags = {
105    Name        = "cloudcasts-${var.infra_env}-private-sg"
106    Role        = "private"
107    Project     = "cloudcasts.io"
108    Environment = var.infra_env
109    ManagedBy   = "terraform"
110  }
111}
112 
113module "ec2_app" {
114  source = "../../modules/ec2"
115 
116  infra_env = var.infra_env
117  infra_role = "web"
118  instance_size = "t3.small"
119  instance_ami = data.aws_ami.app.id
120  # instance_root_device_size = 12
121  subnets = data.aws_subnet_ids.public_subnets.ids
122  security_groups = data.aws_security_groups.public_sg.ids
123  tags = {
124    Name = "cloudcasts-${var.infra_env}-web"
125  }
126  create_eip = true
127}
128 
129module "ec2_worker" {
130  source = "../../modules/ec2"
131 
132  infra_env = var.infra_env
133  infra_role = "worker"
134  instance_size = "t3.large"
135  instance_ami = data.aws_ami.app.id
136  instance_root_device_size = 20
137  subnets = data.aws_subnet_ids.private_subnets.ids
138  security_groups = data.aws_security_groups.private_sg.ids
139  tags = {
140    Name = "cloudcasts-${var.infra_env}-worker"
141  }
142  create_eip = false
143}

File modules/vpc/main.tf

We also needed to add some additional tags to the public and private subnets that the VPC module creates. To do that, we found some variables we can use included in the community VPC module.

We could easily add some tags that way to differentiate public vs private subnets!

 1module "vpc" {
 2  source  = "terraform-aws-modules/vpc/aws"
 3  version = "2.77.0"
 4 
 5  # insert the 49 required variables here
 6  name = "cloudcasts-${var.infra_env}-vpc"
 7  cidr = var.vpc_cidr
 8 
 9  azs = var.azs
10 
11  # Single NAT Gateway, see docs linked above
12  enable_nat_gateway = true
13  single_nat_gateway = true
14  one_nat_gateway_per_az = false
15 
16  private_subnets = var.private_subnets
17  public_subnets  = var.public_subnets
18  database_subnets = var.database_subnets
19 
20  tags = {
21    Name = "cloudcasts-${var.infra_env}-vpc"
22    Project = "cloudcasts.io"
23    Environment = var.infra_env
24    ManagedBy = "terraform"
25  }
26 
27  # NEW ITEMS HERE:
28  private_subnet_tags = {
29    Role = "private"
30  }
31 
32  public_subnet_tags = {
33    Role = "public"
34  }
35}

Then we can init/plan/apply these changes:

1# Apply our additional tags to our subnets:
2./run production compute plan
3./run production compute apply
4 
5# Init our new stage area, plan, and apply
6./run production compute init
7./run production compute plan
8./run production compute apply