7. TERRAFORM

INFRASTRUCTURE:
resources used to run our application on cloud.
ex: ec2, s3, elb, vpc --------------


in genral we used to deploy infra on manual 

Manual:
1. time consume
2. manual work
3. commiting mistakes

Automate -- > Terraform -- > code -- > hcl (Hashicorp configuration languge)



its a tool used to make infrastructure automation.
its a free and opensource.
its platform independent.
it comes on year 2014.
who: mitchel hasimoto 
ownde: hasicorp 
terraform is written on go language.
We can call terraform as IAAC TOOL.

HOW IT WORKS:
terraform uses code to automate the infra.
we use HCL : HashiCorp Configuration Language.

IAAC: Infrastructure as a code.

Code --- > execute --- > Infra 

ADVANTGAES:
1. Reuseable 
2. Time saving
3. Automation
4. Avoiding mistakes
5. Dry run


CFT = AWS
ARM = AZURE
GDE = GOOGLE

TERRAFROM = ALL CLOUDS

INSTALLING TERRAFORM:

sudo yum install -y yum-utils shadow-utils
sudo yum-config-manager --add-repo https://rpm.releases.hashicorp.com/AmazonLinux/hashicorp.repo
sudo yum -y install terraform
aws configure


mkdir terraform
cd terraform

vim main.tf 

provider "aws" {
region = "us-east-1"
}

resource "aws_instance" "one" {
ami = "ami-03eb6185d756497f8"
instance_type = "t2.micro"
}


TERRAFORM COMMANDS:
terraform init	: initalize the provider plugins on backend
terraform plan	: to create execution plan
terrafrom apply : to create resources
terrafrom destroy : to delete resources

provider "aws" {
region = "ap-south-1"
}

resource "aws_instance" "one" {
count = 5
ami = "ami-0b41f7055516b991a"
instance_type = "t2.micro"
}

terraform apply --auto-approve
terraform destroy --auto-approve


STATE FILE: used to store the resource information which is created by terraform
to track the resource activities
in real time entire resource info is on state file.
we need to keep it safe
if we lost this file we cant track the infra.
Command:
terraform state list

terrafrom target: used to destroy the specific resource 
terraform state list
single target: terraform destroy -target="aws_instance.one[3]"
multi targets: terraform destroy -target="aws_instance.one[1]" -target="aws_instance.one[2]"


TERRAFORM VARIABLES:
provider "aws" {
region = "ap-south-1"
}

resource "aws_instance" "one" {
count = var.instance_count
ami = "ami-0b41f7055516b991a"
instance_type = var.instance_type
}

variable "instance_type" {
description = "*"
type = string
default = "t2.micro"
}

variable "instance_count" {
description = "*"
type = number
default = 5
}

terraform apply --auto-approve
terraform destroy --auto-approve

history:
 1  aws configure
    2  sudo yum install -y yum-utils
    3  sudo yum-config-manager --add-repo https://rpm.releases.hashicorp.com/AmazonLinu                                                                                                                                                                                                                            x/hashicorp.repo
    4  sudo yum -y install terraform
    5  terraform -v
    6  mdkir terraform
    7  mkdir terraform
    8  cd terraform/
    9  vim main.tf
   10  terraform init
   11  terraform plan
   12  terraform apply
   13  vim main.tf
   14  terraform apply
   15  ll
   16  cat terraform.tfstate
   17  terraform destroy
   18  cat terraform.tfstate
   19  vim main.tf
   20  terraform plan
   21  terraform apply
   22  cat terraform.tfstate
   23  terraform state list
   24  terraform destroy -target="aws_instance.one[4]"
   25  terraform state list
   27  terraform destroy --auto-approve -target="aws_instance.one[3]" -target="aws_instance.one[2]"                                                                                                                                                                                                                         ance.one[0]"
   28  terraform state list
   29  terraform destroy --auto-approve
   30  vim main.tf
   31  terraform plan
   32  terraform apply --auto-approve
   33  vim main.tf
   34  terraform apply --auto-approve
   35  terraform state list
   36  terraform destroy --auto-apporve
   37  terraform destroy --auto-approve
   38  history

=========================================
VARIABLES, OUTPUTS AND IMPORT

TERRAFORM VAR FILES:
these files used to store variables seperately on terraform.



cat main.tf
provider "aws" {
region = "us-east-1"
}

resource "aws_instance" "one" {
count = var.instance_count
ami = "ami-03eb6185d756497f8"
instance_type = var.instance_type
tags = {
Name = "raham-server"
}
}

cat variable.tf
variable "instance_count" {
description = "*"
type = number
default = 3
}

variable "instance_type" {
description = "*"
type = string
default = "t2.micro"
}

terraform apply --auto-approve 
terraform destroy --auto-approve


cat main.tf
provider "aws" {
region = "ap-south-1"
}

resource "aws_instance" "one" {
count = var.instance_count
ami = "ami-0b41f7055516b991a"
instance_type = var.instance_type
tags = {
Name = "raham-server"
}
}

cat variable.tf
variable "instance_count" {
}

variable "instance_type" {
}

cat dev.tfvars
instance_count = 1

instance_type = "t2.micro"

cat test.tfvars
instance_count = 2

instance_type = "t2.medium"

terraform apply --auto-approve -var-file="dev.tfvars"
terraform destroy --auto-approve -var-file="dev.tfvars"


terraform apply --auto-approve -var-file="test.tfvars"
terraform destroy --auto-approve -var-file="test.tfvars"


TERRAFORM CLI:
we can pass inputs for terraform from cli.

provider "aws" {
region = "ap-south-1"
}

resource "aws_instance" "one" {
ami = "ami-0b41f7055516b991a"
instance_type = var.instance_type
tags = {
Name = "raham-server"
}
}

variable "instance_type" {
}

terraform apply --auto-approve -var="instance_type=t2.medium"
terraform destroy --auto-approve -var="instance_type=t2.medium"

TERRAFORM OUTPUTS: used to print the resource properties.
ex: public-ip, dns, instance type

provider "aws" {
region = "ap-south-1"
}

resource "aws_instance" "one" {
ami = "ami-0b41f7055516b991a"
instance_type = "t2.medium"
tags = {
Name = "raham-server"
}
}

output "raham" {
value = [aws_instance.one.public_ip, aws_instance.one.private_ip, aws_instance.one.public_dns, aws_instance.one.private_dns]
}


TERRAFORM IMPORT: used to import and track the resources which is created manually.


cat main.tf
provider "aws" {
region = "ap-south-1"
}

resource "aws_instance" "one" {
}

terraform import aws_instance.one i-0f4c0d5d3bb6dc758

  1  sudo yum install -y yum-utils shadow-utils
    2  sudo yum-config-manager --add-repo https://rpm.releases.hashicorp.com/AmazonLinux/hashicorp.repo
    3  sudo yum -y install terraform
    4  aws configure
    5  mkdir terraform
    6  cd terraform/
    7  vim main.tf
    8  vim variable.tf
    9  cat main.tf
   10  cat variable.tf
   11  terraform init
   12  terraform plan
   13  cd
   14  ls -al
   15  ll .aws/
   16  vim .aws/credentials
   17  cd terraform/
   18  terraform plan
   19  vim main.tf
   20  terraform plan
   21  vim main.tf
   22  terraform plan
   23  terraform apply --aut-approve
   24  terraform apply --auto-approve
   25  vim main.tf
   26  terraform apply --auto-approve
   27  terraform destroy --auto-approve
   28  vim variable.tf
   29  vim dev.tfvars
   30  vim test.tfvars
   31  cat main.tf
   32  cat variable.tf
   33  cat dev.tfvars
   34  cat test.tfvars
   35  terraform apply --auto-approve -var-file="dev.tfvars"
   36  terraform apply --auto-approve -var-file="test.tfvars"
   37  terraform destroy --auto-approve -var-file="test.tfvars"
   38  vim dev.tfvars
   39  terraform apply --auto-approve
   40  terraform apply --auto-approve -var-file="dev.tfvars"
   41  terraform destroy --auto-approve -var-file="dev.tfvars"
   42  rm -rf dev.tfvars test.tfvars variable.tf
   43  vim main.tf
   44  ll
   45  terraform apply --auto-approve
   46  terraform destroy --auto-approve
   47  terraform apply --auto-approve -var="instance_type=t2.medium"
   48  terraform destroy --auto-approve -var="instance_type=t2.medium"
   49  vim main.tf
   50  terraform apply --auto-approve
   51  vim main.tf
   52  terraform apply
   53  vim main.tf
   54  terraform apply --auto-approve
   55  terraform destroy --auto-approve
   56  vim main.tf
   57  cat terraform.tfstate
   58  vim main.tf
   59  cat main.tf
   60  terraform import aws_instance.one i-0f4c0d5d3bb6dc758
   61  cat terraform.tfstate
   62  terraform import --help
   63  terraform import -h

===================================================


provider "aws" {
region = "us-east-1"
}

resource "aws_s3_bucket" "one" {
bucket = "rahamshaik9988tetrrbcuket"
}

resource "aws_ebs_volume" "two" {
size = 20
availability_zone = "us-east-1b"
tags = {
Name = "raham-ebs"
}
}

resource "aws_iam_user" "three" {
name = "rahams"
}

resource "aws_instance" "four" {
ami = "ami-03eb6185d756497f8"
instance_type = "t2.micro"
tags = {
Name = "Raham-terraserver"
}
}

Terraform taint: used to recreate specific objects 
in real time some resource we need to recrete if it will not work properly 
then we can use taint concetp

terraform taint aws_instance.four
terraform apply --auto-approve

Terraform Lifecycle:

Prevent_destroy: used to keep secure our resources without destroying.

provider "aws" {
region = "us-east-1"
}

resource "aws_s3_bucket" "one" {
bucket = "rahamshaik9988tetrrbcuket"
}

resource "aws_ebs_volume" "two" {
size = 20
availability_zone = "us-east-1b"
tags = {
Name = "raham-ebs"
}
}

resource "aws_iam_user" "three" {
name = "rahams"
}

resource "aws_instance" "four" {
ami = "ami-03eb6185d756497f8"
instance_type = "t2.micro"
tags = {
Name = "Raham-terraserver"
}
lifecycle {
prevent_destroy = true
}

TERRAFORM FMT: used to provide the indentation for terraform.

VERSION CONSTARINT: used to change the provider version.

provider "aws" {
  region = "us-east-1"
}

terraform {
  required_providers {
    aws = {
      source = "hashicorp/aws"
      version = ">5.19.0"
    }
  }
}

terraform init -upgrade

Local resources:

provider "aws" {
  region = "us-east-1"
}

resource "local_file" "one" {
filename = "abc.txt"
content= "Hai all this file is created by terraform"
}


provider "aws" {
  region = "us-east-1"
}

terraform {
  required_providers {
    local = {
      source = "hashicorp/local"
      version = "2.2.0"
    }
  }
}

HISTORY:
    1  sudo yum install -y yum-utils shadow-utils
    2  sudo yum-config-manager --add-repo https://rpm.releases.hashicorp.com/AmazonLinux/hashicorp.repo
    3  sudo yum -y install terraform
    4  aws configure
    5  mkdir terraform
    6  cd terraform/
    7  vim main.tf
    8  terraform init
    9  terraform plan
   10  vim main.tf
   11  terraform plan
   12  terraform apply --auto-approve
   13  vim main.tf
   14  terraform apply --auto-approve
   15  cat main.tf
   16  vim main.tf
   17  terraform apply --auto-approve
   18  terraform state list
   19  cat main.tf
   20  terraform taint aws_instance.four
   21  terraform apply --auto-approve
   22  terraform state list
   23  terraform taint aws_instance.four aws_ebs_volume.two
   24  terraform taint aws_instance.four
   25  terraform taint aws_ebs_volume.two
   26  terraform apply --auto-approve
   27  vim main.tf
   28  terraform destroy --auto-approve
   29  vim main.tf
   30  terraform destroy --auto-approve
   31  terraform plan
   32  terraform destroy --auto-approve
   33  terraform state list
   34  vim main.tf
   35  terraform destroy --auto-approve
   36  vim main.tf
   37  terraform destroy --auto-approve
   38  cat main.tf
   39  vim main.tf
   40  terraform destroy --auto-approve
   41  terraform apply --auto-approve
   42  terraform destroy --auto-approve
   43  terraform init
   44  vim main.tf
   45  cat main.tf
   46  terraform fmt
   47  cat main.tf
   48  vim main.tf
   49  terraform init -upgrade
   50  vim main.tf
   51  terraform init -upgrade
   52  vim main.tf
   53  terraform init -upgrade
   54  cat main.tf
   55  vim main.tf
   56  terraform apply --auto-approve
   57  terraform init -upgrade
   58  terraform apply --auto-approve
   59  ll /root/
   60  ll
   61  cd
   62  ll
   63  cd terraform/
   64  ll
   65  cat abc.txt
   66  cat main.tf
   67  vim main.tf
   68  terraform init -upgrade
   69  vim main.tf
   70  terraform init -upgrade
   71  cat main.tf
   72  history



======================================================================================

TERRAFORM LOCALS:
its a block used to define the values.
we can define the vaule once and used it for multiple times.

provider "aws" {
region = "ap-south-1"
}

locals {
env = "test"
}

resource "aws_vpc" "one" {
cidr_block = "10.0.0.0/16"
tags = {
Name = "${local.env}-vpc"
}
}

resource "aws_subnet" "two" {
cidr_block = "10.0.0.0/16"
availability_zone = "ap-south-1a"
vpc_id = aws_vpc.one.id
tags = {
Name = "${local.env}-subnet"
}
}

resource "aws_instance" "three" {
subnet_id = aws_subnet.two.id
ami = "ami-06006e8b065b5bd46"
instance_type = "t2.micro"
tags = {
Name = "${local.env}-server"
}
}

TERRAFORM WORKSPACE:
WORKSPACE: Where we write the code and execute operations.
it is used to isolate the env.
in real time all the works we do on workspaces only.
if we perform an operation on one workspace it wont affect another workspace.


NOTE:
1. we can't delete our current workspace.
2. we can't delete our workspace without deleting resources.
3. we cant't delete default workspace.

COMMANDS:

terraform workspace list	: to list workspaces
terraform workspace new dev	: to create a new workspace	
terraform workspace show	: to show current workspace
terraform workspace select prod	: to switch the workspaces
terraform workspace delete prod	: to delete the workspaces


provider "aws" {
region = "ap-south-1"
}

locals {
env = "${terraform.workspace}"
}

resource "aws_vpc" "one" {
cidr_block = "10.0.0.0/16"
tags = {
Name = "${local.env}-vpc"
}
}

resource "aws_subnet" "two" {
cidr_block = "10.0.0.0/16"
availability_zone = "ap-south-1a"
vpc_id = aws_vpc.one.id
tags = {
Name = "${local.env}-subnet"
}
}

resource "aws_instance" "three" {
subnet_id = aws_subnet.two.id
ami = "ami-06006e8b065b5bd46"
instance_type = "t2.micro"
tags = {
Name = "${local.env}-server"
}
}


TERRAFORM GRAPH: used to show the flow chart of our infra
terraform graph
copy paste the content in graphviz online


ALIAS AND PROVIDER: used to create resources on mutliple regions in single file.

provider "aws" {
region = "ap-south-1"
}

resource "aws_instance" "three" {
ami = "ami-06006e8b065b5bd46"
instance_type = "t2.large"
tags = {
Name = "mumbai-server"
}
}

provider "aws" {
region = "ap-northeast-1"
alias = "tokyo"
}

resource "aws_instance" "four" {
provider = aws.tokyo
ami = "ami-0bcf3ca5a6483feba"
instance_type = "t2.large"
tags = {
Name = "tokyo-server"
}
}

HISTORY:
  1  sudo yum install -y yum-utils shadow-utils
    2  sudo yum-config-manager --add-repo https://rpm.releases.hashicorp.com/AmazonLinux/hashicorp.repo
    3  sudo yum -y install terraform
    4  aws configure
    5  vim .aws/config
    6  mkdir terraform
    7  cd
    8  cd terraform/
    9  vim main.tf
   10  terraform init
   11  vim main.tf
   12  terraform init
   13  terraform validate
   14  vim main.tf
   15  terraform validate
   16  vim main.tf
   17  terraform validate
   18  terraform plan
   19  terraform apply --auto-approve
   20  terraform state list
   21  vim main.tf
   22  terraform apply --auto-approve
   23  terraform destroy --auto-approve
   24  vim main.tf
   25  terraform workspace list
   26  terraform workspace new dev
   27  terraform workspace list
   28  terraform workspace show
   29  vim main.tf
   30  terraform apply --auto-approve
   31  terraform state list
   32  terraform workspace new test
   33  terraform state list
   34  vim m
   35  vim main.tf
   36  terraform apply --auto-approve
   37  terraform workspace new prod
   38  vim main.tf
   39  terraform apply --auto-approve
   40  vim main.tf
   41  terraform apply --auto-approve
   42  vim main.tf
   43  terraform apply --auto-approve
   44  terraform workspace show
   45  terraform workspace delete prod
   46  terraform workspace delete test
   47  terraform destroy --auto-approve
   48  terraform workspace select test
   49  terraform workspace delete prod
   50  terraform workspace list
   51  terraform destroy --auto-approve
   52  terraform workspace select dev
   53  terraform workspace delete test
   54  terraform state list
   55  terraform graph
   56  terraform destroy --auto-approve
   57  vim main.tf
   58  terraform apply --auto-approve
   59  vim main.tf
   60  terraform apply --auto-approve
   61  cat main.tf
   62  history
=====================================================

provider "aws" {
region = "ap-south-1"
}

resource "aws_instance" "one" {
ami = "ami-06006e8b065b5bd46"
instance_type = "t2.micro"
tags = {
Name = "raham"
}
lifecycle {
prevent_destroy = true
}
}


provider "aws" {
region = "ap-south-1"
}

resource "aws_instance" "one" {
ami = "ami-06006e8b065b5bd46"
instance_type = "t2.micro"
tags = {
Name = "raham"
}
lifecycle {
prevent_destroy = false
}
}

Prevent Destroy: it will not delete the resources
Ignore changes: it will not replicate the changes we have done to server
Depends on: it will depend on another resource to create.

tERRAFORM REMOTE BACKEND SETUP:
when we create infra the information of resources will store on state file.
so it will be tracking the infra information.
so we need to take backup of that file.
if we lost that file we cant track the infra.
so we prefer to locate the state file on remote loaction.
here im using s3 as remote backend.


provider "aws" {
region = "ap-south-1"
}

terraform {
  backend "s3" {
    bucket = "rahamshaikterraprodbcuket0088"
    key    = "prod/terraform.tfstate"
    region = "ap-south-1"
  }
}

resource "aws_instance" "one" {
ami = "ami-06006e8b065b5bd46"
instance_type = "t2.micro"
tags = {
Name = "raham"
}
}

create Bucket manually

Note: while using new block always we need to run terraform init
otherwise, plugins will not be downloaded

after removing backend setup run this command:
terraform init -migrate-state


TERRAFORM REFRESH: used to refresh and replicate the changes to state file.
it will compare terraform state file with resource.
if it is exsits it will show, otherwise it will not show.

LOCAL RESOURCES:


provider "aws" {
region = "ap-south-1"
}

resource "local_file" "one" {
filename = "abc.txt"
content = "hai all this file is creatd from terraform"
}

VERSION CONSTRAINTS:
it is used to change the provider version plugins.
can be applicable for all providers.


provider "aws" {
region = "ap-south-1"
}

terraform {
  required_providers {
    aws = {
      source = "hashicorp/aws"
      version = "<5.22.0"
    }
  }
}


provider "aws" {
region = "ap-south-1"
}

terraform {
  required_providers {
    local = {
      source = "hashicorp/local"
      version = "<2.2.0"
    }
  }
}



DYNAMIC BLOCK: it is used to reduce the length of code and used for reusabilty of code in loop.

provider "aws" {
}

locals {
  ingress_rules = [{
    port        = 443
    description = "Ingress rules for port 443"
    },
    {
      port        = 80
      description = "Ingree rules for port 80"
  },
  {
      port        = 8080
      description = "Ingree rules for port 8080"

  }]
}

resource "aws_instance" "ec2_example" {
  ami                    = "ami-0c02fb55956c7d316"
  instance_type          = "t2.micro"
  vpc_security_group_ids = [aws_security_group.main.id]
  tags = {
    Name = "Terraform EC2"
  }
}

resource "aws_security_group" "main" {

  egress = [
    {
      cidr_blocks      = ["0.0.0.0/0"]
      description      = "*"
      from_port        = 0
      ipv6_cidr_blocks = []
      prefix_list_ids  = []
      protocol         = "-1"
      security_groups  = []
      self             = false
      to_port          = 0
  }]

  dynamic "ingress" {
    for_each = local.ingress_rules

    content {
      description = "*"
      from_port   = ingress.value.port
      to_port     = ingress.value.port
      protocol    = "tcp"
      cidr_blocks = ["0.0.0.0/0"]
    }
  }

  tags = {
    Name = "terra sg"
  }
}



provider "aws" {
region = "ap-south-1"
}

resource "aws_instance" "one" {
count = length(var.instance_type)
ami = "ami-06006e8b065b5bd46"
instance_type = var.instance_type[count.index]
tags = {
Name = var.instance_name[count.index]
}
}

variable "instance_type" {
default = ["t2.medium", "t2.micro", "t2.nano"]
}

variable "instance_name" {
default = ["webserver", "appserver", "dbserver"]
}


FOR_EACH:

provider "aws" {
}

resource "aws_instance" "two" {
for_each = toset(["web-server", "app-server", "db-server"])
ami = "ami-04beabd6a4fb6ab6f"
instance_type = "t2.micro"
tags = {
Name = "${each.key}"
}
}