Terraform IaC Sheet: Provisioning & State Ops

💡 Terraform IaC Sheet: Provisioning & State Ops — Executive Summary

Technical architectural analysis, practical configuration manifests, and deployment instructions for Terraform IaC Sheet: Provisioning & State Ops.

Setup

brew:
snap:
bash
```
sudo snap install terraform --classic
```

amd64:

bash

sudo apt update
sudo apt install unzip
wget -q https://releases.hashicorp.com/terraform/1.4.5/terraform_1.4.5_linux_amd64.zip
unzip terraform_1.4.5_linux_amd64.zip
rm terraform_1.4.5_linux_amd64.zip
sudo mv terraform /usr/local/bin/terraform
terraform version

Getting start

bash

# 최초 .tf파일 작성 후
terraform init
find .terraform
>>>
.terraform
.terraform/providers
.terraform/providers/registry.terraform.io
.terraform/providers/registry.terraform.io/cloudflare
.terraform/providers/registry.terraform.io/cloudflare/cloudflare
.terraform/providers/registry.terraform.io/cloudflare/cloudflare/4.45.0
.terraform/providers/registry.terraform.io/cloudflare/cloudflare/4.45.0/darwin_arm64
.terraform/providers/registry.terraform.io/cloudflare/cloudflare/4.45.0/darwin_arm64/LICENSE
.terraform/providers/registry.terraform.io/cloudflare/cloudflare/4.45.0/darwin_arm64/CHANGELOG.md
.terraform/providers/registry.terraform.io/cloudflare/cloudflare/4.45.0/darwin_arm64/terraform-provider-cloudflare_v4.45.0
.terraform/providers/registry.terraform.io/cloudflare/cloudflare/4.45.0/darwin_arm64/README.md
<<<
terraform plan
terraform apply --auto-approve

Exec

main

bash

Main commands:
  init          Prepare your working directory for other commands
  validate      Check whether the configuration is valid
  plan          Show changes required by the current configuration
  apply         Create or update infrastructure
  destroy       Destroy previously-created infrastructure

# directory 내 .tf파일을 읽은 후 provider generate
terraform init

# 유효성 검증
terraform plan

# 변경 사항 적용: 테라폼 구성 파일(.tf 파일)에 정의된 리소스를 클라우드 서비스나 인프라에 추가, 수정 또는 삭제
terraform apply 
# 변경 사항 적용, 자동승인
terraform apply --auto-approve

# 특정 리소스를 제거하거나 전체 인프라를 삭제할 경우 사용. -target 옵션을 사용하면 특정 리소스 지정하여 삭제
terraform destroy -target=cloudflare_record.test01

`import`

bash

# 클라우드에서 현재 인프라상태를 tf파일로 가져옴
terraform import $resource ${filename}.tf

The state of the existing infrastructure can be added to the state of terraform, but the resource file must be written directly.

`refresh`

bash

# .tf파일을 클라우드 리소스의 실제 상태와 동기화
terraform refresh

`apply` vs `refresh`

terraform apply:
– Purpose: Apply changes in configuration files to real infrastructure.
– Change infrastructure: Yes, we actually change infrastructure.
– Update state file: Update the state file after changes.
– Yes: Create a new resource or modify an existing resource.
terraform refresh:
– Purpose: Synchronize the current infrastructure state with the state file.
– Infrastructure changes: No, it will not affect the infrastructure.
– Update state file: Update only the state file.
– Yes: Reflects resources that have been manually changed externally.

state

bash

# 상태 파일에 있는 모든 리소스를 나열합니다.
terraform state list
terraform state list $resource

# 특정 리소스를 상태 파일에서 제거합니다(이후 리소스 재생성을 위해 사용).
terraform state rm $resouce

# 리소스를 상태 파일 내에서 다른 이름이나 위치로 이동합니다.
terraform state mv ?

console

bash

# exec
terraform console

in Console

The terraform console command will read the Terraform configuration in the current working directory and the Terraform state file from the configured backend so that interpolations can be tested against both the values in the configuration and the state file.

With the following main.tf:

bash

variable "apps" {
  type = map(any)
  default = {
    "foo" = {
      "region" = "us-east-1",
    },
    "bar" = {
      "region" = "eu-west-1",
    },
    "baz" = {
      "region" = "ap-south-1",
    },
  }
}

resource "random_pet" "example" {
  for_each = var.apps
}

Executing terraform console will drop you into an interactive shell where you can test interpolations to:

Print a value from a map:

bash

> var.apps.foo
{
  "region" = "us-east-1"
}

Filter a map based on a specific value:

bash

> { for key, value in var.apps : key => value if value.region == "us-east-1" }
{
  "foo" = {
    "region" = "us-east-1"
  }
}

Check if certain values may not be known until apply:

bash

> random_pet.example
(known after apply)

Test various functions:

bash

> cidrnetmask("172.16.0.0/12")
"255.240.0.0"

Features

Reflecting existing resources in terraform state

bash

#terraform import cloudflare_record.terraform_managed_resource_8334085269f2bfedeec66692be31e568_0 ee7cc1e47eda0114152493a289367e3f/8334085269f2bfedeec66692be31e568
# zone resource
terraform import ${resource_type}.${record_name} zones/${zone_id}/${record_id}
# account resource
terraform import ${resource_type}.${record_name} accounts/${account_id}/${record_id}

Scenario

bash

# already exist 발생
terraform apply
>>>
│ Error: expected DNS record to not already be present but already exists
│
│   with cloudflare_record.terraform_managed_resource_8334085269f2bfedeec66692be31e568_0,
│   on main-cloudflare_record.tf line 1, in resource "cloudflare_record" "terraform_managed_resource_8334085269f2bfedeec66692be31e568_0":
│    1: resource "cloudflare_record" "terraform_managed_resource_8334085269f2bfedeec66692be31e568_0" {
│
╵
╷
│ Error: expected DNS record to not already be present but already exists
│
│   with cloudflare_record.terraform_managed_resource_4481868c29b29cbfe3db0e29b4925cf0_1,
│   on main-cloudflare_record.tf line 10, in resource "cloudflare_record" "terraform_managed_resource_4481868c29b29cbfe3db0e29b4925cf0_1":
│   10: resource "cloudflare_record" "terraform_managed_resource_4481868c29b29cbfe3db0e29b4925cf0_1" {
│
<<<

# 항상 creating 상태
terraform plan
>>>
Terraform will perform the following actions:

  # cloudflare_record.terraform_managed_resource_4481868c29b29cbfe3db0e29b4925cf0_1 will be created
  + resource "cloudflare_record" "terraform_managed_resource_4481868c29b29cbfe3db0e29b4925cf0_1" {
      + allow_overwrite = false
      + content         = "\"f9ab45e0-52b0-494c-b780-1c064cae4a92\""
      + created_on      = (known after apply)
      + hostname        = (known after apply)
      + id              = (known after apply)
      + metadata        = (known after apply)
      + modified_on     = (known after apply)
      + name            = "_cf-custom-hostname"
      + proxiable       = (known after apply)
      + proxied         = false
      + ttl             = 1
      + type            = "TXT"
      + value           = (known after apply)
      + zone_id         = "ee7cc1e47eda0114152493a289367e3f"
    }

  # cloudflare_record.terraform_managed_resource_8334085269f2bfedeec66692be31e568_0 will be created
  + resource "cloudflare_record" "terraform_managed_resource_8334085269f2bfedeec66692be31e568_0" {
      + allow_overwrite = false
      + content         = "domain-placeholder.cloudflare-ui.com"
      + created_on      = (known after apply)
      + hostname        = (known after apply)
      + id              = (known after apply)
      + metadata        = (known after apply)
      + modified_on     = (known after apply)
      + name            = "fredric18.uk"
      + proxiable       = (known after apply)
      + proxied         = true
      + ttl             = 1
      + type            = "CNAME"
      + value           = (known after apply)
      + zone_id         = "ee7cc1e47eda0114152493a289367e3f"
    }
<<<

# import 수행
terraform import ${resource_type}.${record_name} ${zone_id}/${record_id}

# 다시 Planning
terraform plan
>>>
  # cloudflare_record.terraform_managed_resource_4481868c29b29cbfe3db0e29b4925cf0_1 will be updated in-place
  ~ resource "cloudflare_record" "terraform_managed_resource_4481868c29b29cbfe3db0e29b4925cf0_1" {
      + allow_overwrite = false
      + content         = "\"f9ab45e0-52b0-494c-b780-1c064cae4a92\""
        id              = "4481868c29b29cbfe3db0e29b4925cf0"
        name            = "_cf-custom-hostname"
        tags            = []
        # (10 unchanged attributes hidden)
    }

  # cloudflare_record.terraform_managed_resource_8334085269f2bfedeec66692be31e568_0 will be updated in-place
  ~ resource "cloudflare_record" "terraform_managed_resource_8334085269f2bfedeec66692be31e568_0" {
      + allow_overwrite = false
      + content         = "domain-placeholder.cloudflare-ui.com"
        id              = "8334085269f2bfedeec66692be31e568"
        name            = "fredric18.uk"
        tags            = []
        # (10 unchanged attributes hidden)
    }
<<<

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Terraform IaC Sheet: Provisioning & State Ops

Setup

Getting start

Exec

main

import

refresh

apply vs refresh

state

console

in Console

Features

Reflecting existing resources in terraform state

Comments

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`import`

`refresh`

`apply` vs `refresh`