TERRAFORM
Terraform is an open source "Infrastructure as a Code" tool, created by HashiCorp.
It was developed by Mitchell Hashimoto with Go Language in th year 2014 which
All the configuration files used (HashiCorp Configuration Language) language for the
code.
Terraform uses a simple syntax, can provision infrastructure across multiple clouds & On
premises.
It is Cloud Agnostic it means the systems does not depends on single provider.
Infrastructure as Code (IaC): Terraform is a tool used for implementing Infrastructure as
Code. It allows you to define and manage infrastructure configurations in a declarative
manner.
Multi-Cloud Support: Terraform is cloud-agnostic and supports multiple cloud providers
such as AWS, Azure, Google Cloud, and others. It also works with on-premises and hybrid
cloud environments.
Declarative Configuration: Users describe the desired state of their infrastructure in a
configuration file (usually written in HashiCorp Configuration Language - HCL), and Terraform
takes care of figuring out how to achieve that state.
Resource Provisioning: Terraform provisions and manages infrastructure resources like
virtual machines, storage, networks, and more. It creates and updates resources based on the
configuration provided.
State Management: Terraform maintains a state file that keeps track of the current state of
the infrastructure. This file is used to plan and apply changes, ensuring that Terraform can
update resources accurately.
Plan and Apply Workflow: Before making changes, Terraform generates an execution plan,
showing what actions it will take. Users review the plan and then apply it to make the changes
to the infrastructure.
Version Control Integration: Terraform configurations can be versioned using version control
systems like Git. This allows for collaboration, code review, and tracking changes over time.
Modular Configuration: Infrastructure configurations can be organized into modules, making
it easier to reuse and share components across different projects.
Community and Ecosystem: Terraform has a vibrant community and a rich ecosystem of
modules and providers contributed by the community, making it easier to leverage pre-built
solutions for common infrastructure components.
Immutable Infrastructure: Terraform encourages the concept of immutable infrastructure,
where changes to infrastructure are made by replacing existing resources rather than
modifying them in place.
WHAT IS IAAC:
Infrastructure as Code (IaC) is a practice in DevOps that involves managing and
provisioning infrastructure resources using code and automation.
Server automation and configuration management tools can often be used to achieve
IaC. There are also solutions specifically for IaC.
By using these IAAC we can automate the creation of Infrastructure instead of manual
process.
IaC brings the principles of software development to infrastructure management,
allowing for more streamlined and agile operations.
IaC tools, such as Terraform or Ansible, automate the provisioning and management of
infrastructure resources. By defining infrastructure as code, you can create scripts or
playbooks that automatically create, configure, and manage your infrastructure in a
consistent and repeatable manner.
ALTERNATIVES OF TERRAFORM:
AWS -- > CFT (JSON/YAML)
AZURE -- > ARM TEMPLATES (JSON)
GCP -- > CLOUD DEPLOYMENT MANAGER (YAML/ PYTHON)
PULUMI -- (PYTHON, JS, C#, GO & TYPE SCRIPT)
ANSIBLE -- > (YAML)
PUPPET
CHEF
VAGRANT
CROSSPLANE
TERRAFORM SETUP IN UBUNTU:
wget https://releases.hashicorp.com/terraform/1.1.3/terraform_1.1.3_linux_amd64.zip
sudo apt-get install zip -y
Unzip terraform
mv terraform /usr/local/bin/
terraform version
TERRAFORM SETUP IN AMAZON LINUX:
sudo yum-config-manager --add-repo
https://rpm.releases.hashicorp.com/AmazonLinux/hashicorp.repo
sudo yum -y install terraform
TERRAFORM LIFECYCLE:
The Terraform lifecycle refers to the sequence of steps and processes that occur when
working with Terraform to manage infrastructure as code. Here's an overview of the typical
Terraform lifecycle:
Write Configuration:
Users define their infrastructure in a declarative configuration language, commonly
using HashiCorp Configuration Language (HCL).
Initialize:
Run terraform init to initialize a Terraform working directory. This step downloads the
necessary providers and sets up the backend.
Plan:
Run terraform plan to create an execution plan. Terraform compares the desired state
from the configuration with the current state and generates a plan for the changes
required to reach the desired state.
Review Plan:
Examine the output of the plan to understand what changes Terraform intends to
make to the infrastructure. This is an opportunity to verify the planned changes
before applying them.
Apply:
Execute terraform apply to apply the changes outlined in the plan. Terraform makes
the necessary API calls to create, update, or delete resources to align the
infrastructure with the desired state.
Destroy (Optional):
When infrastructure is no longer needed, or for testing purposes, run terraform
destroy to tear down all resources created by Terraform. This is irreversible, so use
with caution.
CREATING EC2 INSTANCE:
Lets assume if we have multiple instances/resources in a terraform, if we want to delete a
single instance/resorce first we have to check the list of resources present in
main.tf file using terraform state listso it will gives the list of entire resources
to delete particular resorce: terraform destroy -target=aws_instance.key[0]
TERRAFORM VARIABLE TYPES:
Input Variables serve as parameters for a Terraform module, so users can customize behavior
without editing the source.
Output Values are like return values for a Terraform module. Local Values are a convenience
feature for assigning a short name to an expression.
TERRAFORM STRING:
It seems like your question might be incomplete or unclear. If you are looking for information
about working with strings in Terraform, I can provide some guidance.
In Terraform, strings are used to represent text data and can be manipulated using various
functions and operators
TERRAFORM NUMBER: The number type can represent both whole numbers and
fractional values .
TERRAFORM BOOLEAN: a boolean represents a binary value indicating either true or
false. Booleans are used to express logical conditions, make decisions, and control the flow of
Terraform configurations. In HashiCorp Configuration Language (HCL), which is used for
writing Terraform configurations, boolean values are written as true or false.
LIST/TUPLE:
MAP/OBJECT:
FOR LOOP:
The for loop is pretty simple and if you have used any programming language before then I
guess you will be pretty much familiar with the for loop.
Only the difference you will notice over here is the syntax in Terraform.
We are going to take the same example by declaring a list(string) and adding three users to it -
user1, user2, user3
Use the above ec2 block if you want
FOR EACH:
The for each is a little special in terraforming and you can not use it on any collection
variable.
Note : - It can only be used on set(string) or map(string).
The reason why for each does not work on list(string) is because a list can contain duplicate
values but if you are using set(string) or map(string) then it does not support duplicate
values.
LOOPS WITH COUNT:
we need to use count but to use the count first we need to declare collections inside our file.
LAUNCH EC2 INSTANCE WITH SG:
TERRAFORM CLI: to pass values form command line during run time
provider "aws" {
resource "aws_instance" "two" {
ami = "ami-0715c1897453cabd1"
instance_type = var.instance_type
tags = {
Name = "web-server"
variable "instance_type" {
terraform apply --auto-approve -var="instance_type=t2.micro"
terraform destroy --auto-approve -var="instance_type=t2.micro"
TERRAFORM OUTPUTS: used to show the properties/metadata of resources
provider "aws" {
resource "aws_instance" "two" {
ami = "ami-0715c1897453cabd1"
instance_type = "t2.micro"
tags = {
Name = "web-server"
output "abc" {
value = [aws_instance.two.public_ip, aws_instance.two.public_dns,
aws_instance.two.private_ip]
ALIAS & PROVIDERS:
provider "aws" {
region = "us-east-1"
}
resource "aws_instance" "one" {
ami = "ami-0715c1897453cabd1"
instance_type = "t2.micro"
tags = {
Name = "web-server"
provider "aws" {
region = "ap-south-1"
alias = "south"
resource "aws_instance" "two" {
provider = "aws.south"
ami = "ami-0607784b46cbe5816"
instance_type = "t2.micro"
tags = {
Name = "web-server"
TERRAFORM WORKSPACE:
In Terraform, a workspace is a way to manage multiple instances of your infrastructure
configurations. Workspaces allow you to maintain different sets of infrastructure within the
same Terraform configuration files. Each workspace has its own state, variables, and
resources, allowing you to manage and deploy distinct environments or configurations.
Default Workspace:
When you initialize a Terraform configuration without explicitly creating a workspace, you
are in the default workspace. The default workspace is often used for the main or
production environment.
Create a Workspace:
You can create additional workspaces using the terraform workspace new
List Workspaces:
To see a list of available workspaces, you can use: terraform workspace list
Select a Workspace:
Use the terraform workspace select command to switch between workspaces: terraform
workspace select dev
Destroy Specific Workspace:
You can destroy resources for a specific workspace using: terraform workspace select
dev && terraform destroy
TERRAFORM CODE TO CREATE S3 BUCKET:
resource "aws_s3_bucket" "one" {
bucket = "my-bucket-name"
resource "aws_s3_bucket_ownership_controls" "two" {
bucket = aws_s3_bucket.one.id
rule {
object_ownership = "BucketOwnerPreferred"
resource "aws_s3_bucket_acl" "three" {
depends_on = [aws_s3_bucket_ownership_controls.two]
bucket = aws_s3_bucket.one.id
acl = "private"
resource "aws_s3_bucket_versioning" "three" {
bucket = aws_s3_bucket.one.id
versioning_configuration {
status = "Enabled"
TERRAFORM CODE TO CREATE VPC:
resource "aws_vpc" "abc" {
cidr_block = "10.0.0.0/16"
instance_tenancy = "default"
enable_dns_hostnames = "true"
tags = {
Name = "my-vpc"
resource "aws_subnet" "mysubnet" {
vpc_id = aws_vpc.abc.id
cidr_block = "10.0.0.0/16"
availability_zone = "ap-south-1a"
tags = {
Name = "subnet-1"
resource "aws_internet_gateway" "igw" {
vpc_id = aws_vpc.abc.id
tags = {
Name = "my-igw"
resource "aws_route_table" "myrt" {
vpc_id = aws_vpc.abc.id
route {
cidr_block = "0.0.0.0/0"
gateway_id = aws_internet_gateway.igw.id
tags = {
Name = "my-route-table"
TERRAFORM CODE TO CREATE EBS:
resource "aws_ebs_volume" "example" {
availability_zone = "us-west-2a"
size = 40
tags = {
Name = "Volume-1"
TERRAFORM CODE TO CREATE EFS:
provider "aws" {
region = "us-east-1"
resource "aws_efs_file_system" "foo" {
creation_token = "my-product"
tags = {
Name = "swiggy-efs"
TERRAFORM MODULES:
is a container where you can create multiple resources. Used to create .tf files in the directory
structure.
main.tf
module "my_instance_module" {
source = "./modules/instances"
ami = “ami-0a2457eba250ca23d"
instance_type = "t2.micro"
instance_name = " rahaminstance"
module "s3_module" {
source = "./modules/buckets"
bucket_name = "rahamshaik009988"
provider.tf
provider "aws" {
region = "us-east-1"
modules/instances/main.tf
resource "aws_instance" "my_instance" {
ami = var.ami
instance_type = var.instance_type
tags = {
Name = var.instance_name
Modules/instances/variable.tf
variable "ami" {
type = string
variable "instance_type" {
type = string
variable "instance_name" {
description = "Value of the Name tag for the EC2 instance"
type = string
Modules/buckets/main.tf
resource "aws_s3_bucket" "b" {
bucket = var.bucket_name
Modules/buckets/variable.tf
variable "bucket_name" {
type = string
validate: will check only configuration
plan: will check errors on code
apply: will check the values
TERRAFORM ADVANTAGES:
Readable code.
Dry run.
Importing of Resources is easy.
Creating of multiple resources.
Can create modules for repeatable code.
TERRAFORM DISADVANTAGES:
Currently under development. Each month, we release a beta version.
There is no error handling
There is no way to roll back. As a result, we must delete everything and re-run code.
A few things are prohibited from import.
Bugs
