This is a sample terraform script which shows how you can deploy VPC, subnet, routes, instance and output the instance’s public ip. We want to use this environment for Jenkins. So, we have added a keyword called “jenk” in all the resources to recognize them easily in AWS.
Sample script
Variables file(file name variables.tfvars):
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aws_access_key = ""
aws_secret_key = ""
aws_ssh_key_name = ""
private_key_path = ""
jenkregion = ""
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Terraform script:
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variable "aws_access_key" {}
variable "aws_secret_key" {}
variable "jenkregion" {}
variable "aws_ssh_key_name" {}
variable "private_key_path" {}
variable "vpcCidr" {
default = "10.0.0.0/16"
}
variable "subnetcidr" {
default = "10.0.0.0/24"
}
variable "az" {
default = "ap-south-1a"
}
provider "aws" {
access_key = var.aws_access_key
secret_key = var.aws_secret_key
region = var.jenkregion
}
#create vpc
resource "aws_vpc" "jenkVPC" {
cidr_block = var.vpcCidr
tags = {
"Name" = "jenkVPC"
}
}
#create subnet
resource "aws_subnet" "jenksubnet" {
cidr_block = var.subnetcidr
vpc_id = aws_vpc.jenkVPC.id
map_public_ip_on_launch = "true"
availability_zone = data.aws_availability_zones.available.names[0]
tags = {
"Name" = "jenksubnet"
}
}
# Internet Gateway
resource "aws_internet_gateway" "jenkInternetGateway" {
vpc_id = aws_vpc.jenkVPC.id
tags = {
"Name" = "JenkIntGateway"
}
}
# Route table
resource "aws_route_table" "jenkRouteTable" {
vpc_id = aws_vpc.jenkVPC.id
tags = {
"Name" = "JenkRouteTable"
}
}
resource "aws_route" "jenkroute" {
gateway_id = aws_internet_gateway.jenkInternetGateway.id
route_table_id = aws_route_table.jenkRouteTable.id
destination_cidr_block = "0.0.0.0/0"
}
# Route table association
resource "aws_route_table_association" "jenksubnetassociation" {
subnet_id = aws_subnet.jenksubnet.id
route_table_id = aws_route_table.jenkRouteTable.id
}
resource "aws_security_group" "jenksecuritygroup" {
vpc_id = aws_vpc.jenkVPC.id
tags = {
"Name" = "jenkSecurityGroup"
}
}
resource "aws_security_group_rule" "SSHportin" {
description = "Allow SSH port"
type = "ingress"
security_group_id = aws_security_group.jenksecuritygroup.id
from_port = 22
to_port = 22
protocol = "tcp"
cidr_blocks = ["0.0.0.0/0"]
}
resource "aws_security_group_rule" "HTTPportin" {
description = "Allow HTTP port"
type = "ingress"
security_group_id = aws_security_group.jenksecuritygroup.id
from_port = 80
to_port = 80
protocol = "tcp"
cidr_blocks = ["0.0.0.0/0"]
}
resource "aws_security_group_rule" "SSHportout" {
description = "Allow SSH port"
type = "egress"
security_group_id = aws_security_group.jenksecuritygroup.id
from_port = 443
to_port = 443
protocol = "tcp"
cidr_blocks = ["0.0.0.0/0"]
}
resource "aws_security_group_rule" "HTTPportout" {
description = "Allow HTTP port"
type = "egress"
security_group_id = aws_security_group.jenksecuritygroup.id
from_port = 80
to_port = 80
protocol = "tcp"
cidr_blocks = ["0.0.0.0/0"]
}
data "aws_availability_zones" "available" {
state = "available"
}
resource "aws_instance" "JenkinsInstance" {
ami = "ami-068257025f72f470d"
instance_type = "t2.micro"
subnet_id = aws_subnet.jenksubnet.id
vpc_security_group_ids = [aws_security_group.jenksecuritygroup.id]
key_name = var.aws_ssh_key_name
availability_zone = data.aws_availability_zones.available.names[0]
provisioner "file" {
//file copy commands. In the same folder you have this terraform script, you should have a file called script.sh.
//Terraform will copy this file to the aws instance after creation.
source = "script.sh"
destination = "/home/ubuntu/script.sh"
connection {
type = "ssh"
host = self.public_ip
user = "ubuntu"
private_key = "${file("LinuxKeyPair.pem")}"
}
}
root_block_device {
volume_size = 30
}
tags = {
Name = "JenkinsMaster"
}
}
output "instance-dns" {
value = aws_instance.JenkinsInstance.public_ip
}
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Commands to run above script:
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terraform plan -var-file=variables.tfvars
terraform apply -var-file=variables.tfvars
terraform destroy -var-file=variables.tfvars
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Terraform script to deploy another instance by using the resources like security group, VPC, subnet created from above script:
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variable aws_access_key {}
variable aws_secret_key {}
variable aws_ssh_key_name {}
variable private_key_path {}
variable region {}
provider aws {
access_key = var.aws_access_key
secret_key = var.aws_secret_key
region = var.region
}
// Using the data sources we refer to existing resources in aws.
//All the below defined data sources like securitygroup, vpc, subnet are already created by above script. We are referring to them using the data sources as shown below.
data "aws_vpc" "VPC" {
filter {
name = "tag:Name"
values = ["jenkVPC"]
}
}
data "aws_subnet" "subnet" {
filter {
name = "tag:Name"
values = ["jenksubnet"]
}
}
data "aws_availability_zones" "az" {
state = "available"
}
data "aws_security_group" "sg" {
filter {
name = "tag:Name"
values = ["jenkSecurityGroup"]
}
}
resource "aws_instance" "JenkinsInstance" {
ami = "ami-068257025f72f470d"
instance_type = "t2.micro"
subnet_id = data.aws_subnet.subnet.id
vpc_security_group_ids = [data.aws_security_group.sg.id]
key_name = var.aws_ssh_key_name
availability_zone = data.aws_availability_zones.az.names[0]
connection {
type = "ssh"
host = self.public_ip
user = "ubuntu"
private_key = "${file("LinuxKeyPair.pem")}"
}
root_block_device {
volume_size = 30
}
tags = {
Name = "JenkinsNode"
}
}
output "instance-dns" {
value = aws_instance.JenkinsInstance.public_ip
}
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Suggested Article
If you’d like to go through Terraform definitions, you can do it here. All other DevOps categories are listed here: DevOps Tools. Have a look at the posts as per your topic of interest.
Conclusion
In this tutorial, we’ve provided you with a sample Terraform script and its basic usage. We’ve also demonstrated examples for all the topics that are discussed. We hope you have learned something new in this article.
Please feel free to share your thoughts about this article in the comments section below.
