Step-00: Pre-requisite Note
- We are using the
default vpc in us-east-1 region
Step-01: Introduction
- Implement the fix for issue we have faced in
section-05-02 with fix we have developed in section-05-03
Step-02: c7-get-instancetype-supported-per-az-in-a-region.tf
- Copy this from previous
05-03-Utility-Project from file named c2-v3-get-instancetype-supported-per-az-in-a-region.tf
# Get List of Availability Zones in a Specific Region
# Region is set in c1-versions.tf in Provider Block
data "aws_availability_zones" "my_azones" {
filter {
name = "opt-in-status"
values = ["opt-in-not-required"]
}
}
# Check if that respective Instance Type is supported in that Specific Region in list of availability Zones
# Get the List of Availability Zones in a Particular region where that respective Instance Type is supported
data "aws_ec2_instance_type_offerings" "my_ins_type" {
for_each=toset(data.aws_availability_zones.my_azones.names)
filter {
name = "instance-type"
values = ["t3.micro"]
}
filter {
name = "location"
values = [each.key]
}
location_type = "availability-zone"
}
# Basic Output: All Availability Zones mapped to Supported Instance Types
output "output_v3_1" {
value = { for az, details in data.aws_ec2_instance_type_offerings.my_ins_type :
az => details.instance_types }
}
# Filtered Output: Exclude Unsupported Availability Zones
output "output_v3_2" {
value = { for az, details in data.aws_ec2_instance_type_offerings.my_ins_type :
az => details.instance_types if length(details.instance_types) != 0 }
}
# Filtered Output: with Keys Function - Which gets keys from a Map
# This will return the list of availability zones supported for a instance type
output "output_v3_3" {
value = keys({ for az, details in data.aws_ec2_instance_type_offerings.my_ins_type :
az => details.instance_types if length(details.instance_types) != 0 })
}
# Filtered Output: As the output is list now, get the first item from list (just for learning)
output "output_v3_4" {
value = keys({ for az, details in data.aws_ec2_instance_type_offerings.my_ins_type :
az => details.instance_types if length(details.instance_types) != 0 })[0]
}
Step-03: c5-ec2instance.tf
Step-03-01: Update the for_each statement to new one
for_each = toset(keys({ for az, details in data.aws_ec2_instance_type_offerings.my_ins_type :
az => details.instance_types if length(details.instance_types) != 0 }))
Step-03-02: Final look of c5-ec2-instance.tf
# EC2 Instance
resource "aws_instance" "myec2vm" {
ami = data.aws_ami.amzlinux2.id
instance_type = var.instance_type
user_data = file("${path.module}/app1-install.sh")
key_name = var.instance_keypair
vpc_security_group_ids = [ aws_security_group.vpc-ssh.id, aws_security_group.vpc-web.id ]
# Create EC2 Instance in all Availabilty Zones of a VPC
#for_each = toset(data.aws_availability_zones.my_azones.names)
for_each = toset(keys({ for az, details in data.aws_ec2_instance_type_offerings.my_ins_type :
az => details.instance_types if length(details.instance_types) != 0 }))
availability_zone = each.key # You can also use each.value because for list items each.key == each.value
tags = {
"Name" = "For-Each-Demo-${each.key}"
}
}
# Terraform Initialize
terraform init
# Terraform Validate
terraform validate
# Terraform Plan
terraform plan
# Terraform Apply
terraform apply -auto-approve
Observations:
1. Verify Outputs
2. Verify EC2 Instances created via AWS Management Console
Step-05: Clean-Up
# Terraform Destroy
terraform destroy -auto-approve
# Delete Files
rm -rf .terraform*
rm -rf terraform.tfstate*