2. Terraform 변수 사용법(use-variable) - AWS

Overview

2023.04.04 - [Hashicorp] - 1. Terraform 기초 : 설치 및 .tf 파일 설명

 

오늘은 Terraform 의 변수사용법에 대해 알아보려고 한다.

https://developer.hashicorp.com/terraform/language/values/variables

 

 

 

---

Terraform 변수 사용법

먼저 소스코드 주소는 아래와 같다.

https://github.com/somaz94/terraform-study-aws/tree/main/use-variable

GitHub - somaz94/terraform-study-aws: This is terraform-study repostiory

 

소스코드를 받아, 내 환경에 맞게 값을 넣어준다.

 

terraform.tvars 파일만 수정해주면 된다.

 

당연히 키페어와 aws configure은 설정한 상태여야 한다.

2023.03.31 - [AWS] - AWS CLI 정리

AWS CLI 정리

 

 

variable.tf

variable "region" {
  description = "The AWS region to create resources in"
  default     = "us-west-2"
}

variable "instance_type" {
  description = "The EC2 instance type"
  default     = "t2.micro"
}

variable "environment" {
  description = "The environment for the infrastructure (e.g., development, staging, production)"
  type        = string
  default     = "development" # Optional: Provide a default value if desired
}

variable "terraform" {
  description = "This resource means that it was created with terraform (e.g., development, staging, production)"
  type        = string
  default     = "true" # Optional: Provide a default value if desired
}

variable "my_public_ip" {
  description = "Your public IP address in CIDR notation (e.g., x.x.x.x/32)"
  type        = string
}

variable "aws_profile" {
  description = "The AWS CLI profile to use for authentication"
  type        = string
  default     = "somaz" # Optional: Provide a default profile name if desired
}

variable "key_pair_name" {
  description = "The name of the key pair to use for the EC2 instance"
  type        = string
}

• terraform.tvars 파일에 정의하지 않으면 default값이 정의되는 구조이다.

 

terraform.tvars

# terraform.tfvars
region       = "ap-northeast-2"
instance_type = "t2.micro"
environment  = "pratice"
my_public_ip = "x.x.x.x/32" # Replace x.x.x.x with your public IP address
aws_profile  = "your_aws_profile" # Replace "your_aws_profile" with the name of the AWS profile you want to use
key_pair_name = "your_key_pair_name" # Replace "your_key_pair_name" with the name of the key pair you want to use

 

---

 

1. terraform init

새 Terraform 프로젝트를 시작하거나 기존 프로젝트를 복제할 때 실행해야 하는 첫 번째 명령이다. 다음 작업을 수행하여 Terraform 작업 디렉터리를 초기화한다.

 

 

백엔드 초기화(Backend Initialization)

• Terraform 구성이 상태 파일을 저장하기 위한 백엔드를 지정하는 경우 terraform init가 백엔드를 설정하고 구성한다. 상태 파일은 Terraform에서 인프라 리소스를 추적하는 데 사용되므로 특히 팀과 함께 작업할 때 안정적이고 안전한 스토리지 솔루션을 갖추는 것이 중요하다.

 

공급자 다운로드(Provider Download)

• Terraform은 공급자를 사용하여 AWS, Azure, Google Cloud 등과 같은 다양한 서비스와 상호 작용한다. Terraform 구성에서 사용 중인 공급자를 정의하면 terraform init가 Terraform 레지스트리에서 필요한 공급자 플러그인을 다운로드한다. 작업 디렉토리 내의 .terraform 디렉토리에 이러한 플러그인을 캐시하므로 공급자 버전을 변경하거나 새 작업 디렉토리를 초기화하지 않는 한 플러그인을 다시 다운로드할 필요가 없다.

 

공급자 구성(Provider Configuration)

• terraform init는 또한 Terraform 구성 파일에서 정의한 설정을 기반으로 공급자를 구성한다. 여기에는 인증 세부 정보, 특정 API 버전 또는 공급자가 올바르게 작동하는 데 필요한 기타 설정이 포함될 수 있다.

 

$ ls
main.tf  output.tf  terraform.tfvars  variables.tf  version.tf

$ terraform init

Initializing the backend...

Initializing provider plugins...
- Finding latest version of hashicorp/aws...
- Installing hashicorp/aws v4.61.0...
- Installed hashicorp/aws v4.61.0 (signed by HashiCorp)

Terraform has created a lock file .terraform.lock.hcl to record the provider
selections it made above. Include this file in your version control repository
so that Terraform can guarantee to make the same selections by default when
you run "terraform init" in the future.

Terraform has been successfully initialized!

You may now begin working with Terraform. Try running "terraform plan" to see
any changes that are required for your infrastructure. All Terraform commands
should now work.

If you ever set or change modules or backend configuration for Terraform,
rerun this command to reinitialize your working directory. If you forget, other
commands will detect it and remind you to do so if necessary.

 

---

 

2. terraform plan

테라폼 코드로 실행 또는 변경될 인프라 내역을 보여준다.

$ terraform plan

Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the
following symbols:
  + create

Terraform will perform the following actions:

  # aws_instance.ec2 will be created
  + resource "aws_instance" "ec2" {
      + ami                                  = "ami-0a67d09dc01633721"
      + arn                                  = (known after apply)
      + associate_public_ip_address          = (known after apply)
      + availability_zone                    = (known after apply)
      + cpu_core_count                       = (known after apply)
      + cpu_threads_per_core                 = (known after apply)
      + disable_api_stop                     = (known after apply)
      + disable_api_termination              = (known after apply)
      + ebs_optimized                        = (known after apply)
      + get_password_data                    = false
      + host_id                              = (known after apply)
      + host_resource_group_arn              = (known after apply)
      + iam_instance_profile                 = (known after apply)
      + id                                   = (known after apply)
      + instance_initiated_shutdown_behavior = (known after apply)
      + instance_state                       = (known after apply)
      + instance_type                        = "t2.micro"
      + ipv6_address_count                   = (known after apply)
      + ipv6_addresses                       = (known after apply)
      + key_name                             = (known after apply)
      + monitoring                           = (known after apply)
      + outpost_arn                          = (known after apply)
      + password_data                        = (known after apply)
      + placement_group                      = (known after apply)
      + placement_partition_number           = (known after apply)
      + primary_network_interface_id         = (known after apply)
      + private_dns                          = (known after apply)
      + private_ip                           = (known after apply)
      + public_dns                           = (known after apply)
      + public_ip                            = (known after apply)
      + secondary_private_ips                = (known after apply)
      + security_groups                      = (known after apply)
      + source_dest_check                    = true
      + subnet_id                            = (known after apply)
      + tags_all                             = {
          + "Environment" = "pratice"
          + "Terraform"   = "true"
        }
      + tenancy                              = (known after apply)
      + user_data                            = (known after apply)
      + user_data_base64                     = (known after apply)
      + user_data_replace_on_change          = false
      + vpc_security_group_ids               = (known after apply)
    }

  # aws_security_group.allow_ssh will be created
  + resource "aws_security_group" "allow_ssh" {
      + arn                    = (known after apply)
      + description            = "Allow SSH inbound traffic"
      + egress                 = (known after apply)
      + id                     = (known after apply)
      + ingress                = [
          + {
              + cidr_blocks      = [
                  + "xx.xx.xx.xx/32",
                ]
              + description      = ""
              + from_port        = 22
              + ipv6_cidr_blocks = []
              + prefix_list_ids  = []
              + protocol         = "tcp"
              + security_groups  = []
              + self             = false
              + to_port          = 22
            },
        ]
      + name                   = "allow_ssh"
      + name_prefix            = (known after apply)
      + owner_id               = (known after apply)
      + revoke_rules_on_delete = false
      + tags_all               = {
          + "Environment" = "pratice"
          + "Terraform"   = "true"
        }
      + vpc_id                 = (known after apply)
    }

Plan: 2 to add, 0 to change, 0 to destroy.

Changes to Outputs:
  + instance_id                  = (known after apply)
  + public_ip                    = (known after apply)
  + security_group_id            = (known after apply)
  + security_group_ingress_rules = [
      + {
          + cidr_blocks      = [
              + "xx.xx.xx.xx/32",
            ]
          + description      = ""
          + from_port        = 22
          + ipv6_cidr_blocks = []
          + prefix_list_ids  = []
          + protocol         = "tcp"
          + security_groups  = []
          + self             = false
          + to_port          = 22
        },
    ]

───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────

Note: You didn't use the -out option to save this plan, so Terraform can't guarantee to take exactly these actions if
you run "terraform apply" now.

 

---

 

3. terraform apply

Terraform 구성 파일에 설명된 대로 인프라의 원하는 상태에 도달하는 데 필요한 변경 사항을 적용하기 위해 Terraform에서 사용되는 명령이다.

 

구성 로드: Terraform은 정의한 리소스와 원하는 상태를 이해하기 위해 작업 디렉터리에서 구성 파일(예: .tf 파일)을 읽는다.

 

상태 새로 고침: Terraform은 리소스에 대한 최신 정보를 얻기 위해 원격 공급자(예: AWS, Azure, Google Cloud)를 쿼리하여 인프라의 현재 상태를 확인한다. 해당 정보는 Terraform 상태 파일(일반적으로 terraform.tfstate라고 함)에 저장된다.

 

실행 계획 생성: Terraform은 구성 파일의 원하는 상태를 상태 파일의 현재 상태와 비교한다. 그런 다음 Terraform이 원하는 상태에 도달하기 위해 각 리소스에서 수행할 작업(만들기, 업데이트 또는 삭제)을 나열하는 실행 계획을 만든다.

 

확인 메시지 표시: 변경 사항을 적용하기 전에 Terraform은 실행 계획을 표시하고 확인 메시지를 표시한다. 수행할 작업에 대한 요약이 표시되며 "예"를 입력하여 계속 진행할 것인지 확인해야 힌다.

 

변경 사항 적용: 실행 계획을 확인하면 Terraform이 원격 공급자에게 API 호출을 수행하여 변경 사항을 적용하기 시작한다. 필요에 따라 리소스를 생성, 업데이트 또는 삭제하고 인프라의 새 상태를 반영하도록 Terraform 상태 파일을 업데이트한다

 

$ terraform apply
aws_security_group.allow_ssh: Refreshing state... [id=sg-08e39387827a8c39d]

Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the
following symbols:
  + create

Terraform will perform the following actions:

  # aws_instance.ec2 will be created
  + resource "aws_instance" "ec2" {
      + ami                                  = "ami-03221589fd7c8f183"
      + arn                                  = (known after apply)
      + associate_public_ip_address          = (known after apply)
      + availability_zone                    = (known after apply)
      + cpu_core_count                       = (known after apply)
      + cpu_threads_per_core                 = (known after apply)
      + disable_api_stop                     = (known after apply)
      + disable_api_termination              = (known after apply)
      + ebs_optimized                        = (known after apply)
      + get_password_data                    = false
      + host_id                              = (known after apply)
      + host_resource_group_arn              = (known after apply)
      + iam_instance_profile                 = (known after apply)
      + id                                   = (known after apply)
      + instance_initiated_shutdown_behavior = (known after apply)
      + instance_state                       = (known after apply)
      + instance_type                        = "t2.micro"
      + ipv6_address_count                   = (known after apply)
      + ipv6_addresses                       = (known after apply)
      + key_name                             = (known after apply)
      + monitoring                           = (known after apply)
      + outpost_arn                          = (known after apply)
      + password_data                        = (known after apply)
      + placement_group                      = (known after apply)
      + placement_partition_number           = (known after apply)
      + primary_network_interface_id         = (known after apply)
      + private_dns                          = (known after apply)
      + private_ip                           = (known after apply)
      + public_dns                           = (known after apply)
      + public_ip                            = (known after apply)
      + secondary_private_ips                = (known after apply)
      + security_groups                      = (known after apply)
      + source_dest_check                    = true
      + subnet_id                            = (known after apply)
      + tags_all                             = {
          + "Environment" = "pratice"
          + "Terraform"   = "true"
        }
      + tenancy                              = (known after apply)
      + user_data                            = (known after apply)
      + user_data_base64                     = (known after apply)
      + user_data_replace_on_change          = false
      + vpc_security_group_ids               = [
          + "sg-08e39387827a8c39d",
        ]
    }

Plan: 1 to add, 0 to change, 0 to destroy.

Changes to Outputs:
  + instance_id                  = (known after apply)
  + public_ip                    = (known after apply)

Do you want to perform these actions?
  Terraform will perform the actions described above.
  Only 'yes' will be accepted to approve.

  Enter a value: yes

aws_instance.ec2: Creating...
aws_instance.ec2: Still creating... [10s elapsed]
aws_instance.ec2: Still creating... [20s elapsed]
aws_instance.ec2: Still creating... [30s elapsed]
aws_instance.ec2: Creation complete after 31s [id=i-0a0f6345fef2c9479]

Apply complete! Resources: 1 added, 0 changed, 0 destroyed.

Outputs:

instance_id = "i-0a0f6345fef2c9479"
public_ip = "xx.xxx.xxx.xx"
security_group_id = "sg-08e39387827a8c39d"
security_group_ingress_rules = toset([
  {
    "cidr_blocks" = tolist([
      "xx.xx.xx.xx/32",
    ])
    "description" = ""
    "from_port" = 22
    "ipv6_cidr_blocks" = tolist([])
    "prefix_list_ids" = tolist([])
    "protocol" = "tcp"
    "security_groups" = toset([])
    "self" = false
    "to_port" = 22
  },
])

 

인스턴스 접속

$ ssh -i ~/.ssh/somazkey.pem ec2-user@13.125.247.89
The authenticity of host '13.125.247.89 (13.125.247.89)' can't be established.
ECDSA key fingerprint is SHA256:qB1CKVTSuAgErKIaM5liAptF0bEqx3/8HwuAFIsyyAc.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added '13.125.247.89' (ECDSA) to the list of known hosts.
   ,     #_
   ~\_  ####_        Amazon Linux 2023
  ~~  \_#####\
  ~~     \###|
  ~~       \#/ ___   https://aws.amazon.com/linux/amazon-linux-2023
   ~~       V~' '->
    ~~~         /
      ~~._.   _/
         _/ _/
       _/m/'
[ec2-user@ip-172-31-39-50 ~]$ ls
[ec2-user@ip-172-31-39-50 ~]$

 

 

---

4. terraform state list

Terraform 상태 파일에서 현재 추적되는 리소스 목록을 표시하기 위해 Terraform에서 사용되는 명령이다. 상태 파일(일반적으로 terraform.tfstate라고 함)은 Terraform 구성 파일에 정의된 리소스와 원격 공급자(예: AWS, Azure, Google Cloud)에서 생성된 실제 리소스 간의 매핑을 저장한다.

 

 

아래와 같이 tfstate 파일이 생겼다.

$ ls
main.tf  output.tf  terraform.tfstate terraform.tfvars  variables.tf  version.tf

 

terraform의 상태를 확인하는 명령어이다.

$ terraform state list
aws_instance.ec2
aws_security_group.allow_ssh

 

---

5. terraform destroy

현재 Terraform 구성에서 관리 중인 모든 리소스를 삭제하거나 제거하기 위해 Terraform에서 사용되는 명령이다. 이 명령은 일반적으로 인프라를 정리하고 Terraform에서 생성한 모든 리소스를 제거하려는 경우에 사용된다.

 

terraform destroy를 실행하면 Terraform이 다음을 수행합니다.

 

Terraform 구성 파일과 현재 상태 파일을 분석한다.

주의 모든 자원을 파괴할 계획을 세운다.

리소스 destroy를 진행할 것인지 확인하는 메시지가 표시된다.

destroy 계획을 실행하고 인프라에서 리소스를 제거한다.

 

$ terraform destroy
aws_security_group.allow_ssh: Refreshing state... [id=sg-08e39387827a8c39d]
aws_instance.ec2: Refreshing state... [id=i-0a0f6345fef2c9479]

Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the
following symbols:
  - destroy

Terraform will perform the following actions:

  # aws_instance.ec2 will be destroyed
  - resource "aws_instance" "ec2" {
      - ami                                  = "ami-03221589fd7c8f183" -> null
      - arn                                  = "arn:aws:ec2:ap-northeast-2:611841095956:instance/i-0a0f6345fef2c9479" -> null
      - associate_public_ip_address          = true -> null
      - availability_zone                    = "ap-northeast-2c" -> null
      - cpu_core_count                       = 1 -> null
      - cpu_threads_per_core                 = 1 -> null
      - disable_api_stop                     = false -> null
      - disable_api_termination              = false -> null
      - ebs_optimized                        = false -> null
      - get_password_data                    = false -> null
      - hibernation                          = false -> null
      - id                                   = "i-0a0f6345fef2c9479" -> null
      - instance_initiated_shutdown_behavior = "stop" -> null
      - instance_state                       = "running" -> null
      - instance_type                        = "t2.micro" -> null
      - ipv6_address_count                   = 0 -> null
      - ipv6_addresses                       = [] -> null
      - monitoring                           = false -> null
      - placement_partition_number           = 0 -> null
      - primary_network_interface_id         = "eni-0d96819db9cba0ccf" -> null
      - private_dns                          = "ip-172-31-32-143.ap-northeast-2.compute.internal" -> null
      - private_ip                           = "172.31.32.143" -> null
      - public_dns                           = "ec2-xx-xxx-xxx-xx.ap-northeast-2.compute.amazonaws.com" -> null
      - public_ip                            = "xx.xxx.xxx.xx" -> null
      - secondary_private_ips                = [] -> null
      - security_groups                      = [
          - "allow_ssh",
        ] -> null
      - source_dest_check                    = true -> null
      - subnet_id                            = "subnet-04c0af235bda13016" -> null
      - tags                                 = {} -> null
      - tags_all                             = {
          - "Environment" = "pratice"
          - "Terraform"   = "true"
        } -> null
      - tenancy                              = "default" -> null
      - user_data_replace_on_change          = false -> null
      - vpc_security_group_ids               = [
          - "sg-08e39387827a8c39d",
        ] -> null

      - capacity_reservation_specification {
          - capacity_reservation_preference = "open" -> null
        }

      - credit_specification {
          - cpu_credits = "standard" -> null
        }

      - enclave_options {
          - enabled = false -> null
        }

      - maintenance_options {
          - auto_recovery = "default" -> null
        }

      - metadata_options {
          - http_endpoint               = "enabled" -> null
          - http_put_response_hop_limit = 2 -> null
          - http_tokens                 = "required" -> null
          - instance_metadata_tags      = "disabled" -> null
        }

      - private_dns_name_options {
          - enable_resource_name_dns_a_record    = false -> null
          - enable_resource_name_dns_aaaa_record = false -> null
          - hostname_type                        = "ip-name" -> null
        }

      - root_block_device {
          - delete_on_termination = true -> null
          - device_name           = "/dev/xvda" -> null
          - encrypted             = false -> null
          - iops                  = 3000 -> null
          - tags                  = {} -> null
          - throughput            = 125 -> null
          - volume_id             = "vol-00f49a9b3ca06d1b3" -> null
          - volume_size           = 8 -> null
          - volume_type           = "gp3" -> null
        }
    }

  # aws_security_group.allow_ssh will be destroyed
  - resource "aws_security_group" "allow_ssh" {
      - arn                    = "arn:aws:ec2:ap-northeast-2:611841095956:security-group/sg-08e39387827a8c39d" -> null
      - description            = "Allow SSH inbound traffic" -> null
      - egress                 = [] -> null
      - id                     = "sg-08e39387827a8c39d" -> null
      - ingress                = [
          - {
              - cidr_blocks      = [
                  - "14.32.77.203/32",
                ]
              - description      = ""
              - from_port        = 22
              - ipv6_cidr_blocks = []
              - prefix_list_ids  = []
              - protocol         = "tcp"
              - security_groups  = []
              - self             = false
              - to_port          = 22
            },
        ] -> null
      - name                   = "allow_ssh" -> null
      - owner_id               = "611841095956" -> null
      - revoke_rules_on_delete = false -> null
      - tags                   = {} -> null
      - tags_all               = {
          - "Environment" = "pratice"
          - "Terraform"   = "true"
        } -> null
      - vpc_id                 = "vpc-0be33812ca98ab8fa" -> null
    }

Plan: 0 to add, 0 to change, 2 to destroy.

Changes to Outputs:
  - instance_id                  = "i-0a0f6345fef2c9479" -> null
  - public_ip                    = "xx.xxx.xxx.xx" -> null
  - security_group_id            = "sg-08e39387827a8c39d" -> null
  - security_group_ingress_rules = [
      - {
          - cidr_blocks      = [
              - "14.32.77.203/32",
            ]
          - description      = ""
          - from_port        = 22
          - ipv6_cidr_blocks = []
          - prefix_list_ids  = []
          - protocol         = "tcp"
          - security_groups  = []
          - self             = false
          - to_port          = 22
        },
    ] -> null

Do you really want to destroy all resources?
  Terraform will destroy all your managed infrastructure, as shown above.
  There is no undo. Only 'yes' will be accepted to confirm.

  Enter a value: yes

aws_instance.ec2: Destroying... [id=i-0a0f6345fef2c9479]
aws_instance.ec2: Still destroying... [id=i-0a0f6345fef2c9479, 10s elapsed]
aws_instance.ec2: Still destroying... [id=i-0a0f6345fef2c9479, 20s elapsed]
aws_instance.ec2: Destruction complete after 29s
aws_security_group.allow_ssh: Destroying... [id=sg-08e39387827a8c39d]
aws_security_group.allow_ssh: Destruction complete after 1s

Destroy complete! Resources: 2 destroyed.

 

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마무리

다음시간에는 다양한 변수에 대해 공부해보도록 하겠다!

 

---

Reference

 

https://developer.hashicorp.com/terraform/language/state

 

https://developer.hashicorp.com/terraform/language/values/variables