iac_modules/iac-template/terraform-standard

Terraform Bootstrap for S3 Backend & DynamoDB Lock Table

This repository provides bootstrap Terraform modules that must be applied before enabling a Terraform remote backend on AWS. It creates:

• S3 bucket — to store Terraform remote state
• DynamoDB table — to store Terraform state locks

Both modules can be run independently.

• bootstrap-s3/ # S3 state bucket (versioning + SSE)
• bootstrap-dynamodb/ # DynamoDB lock table (LockID)

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** Note: S3 bucket must be emptied before deletion. **

1. AWS Credentials Setup

Terraform reads AWS credentials through the standard AWS credential chain. You may use either A or B.

A. Environment Variables (recommended for local / CI)

export AWS_ACCESS_KEY_ID="AKIAxxxxxxxxxxxx"
export AWS_SECRET_ACCESS_KEY="xxxxxxxxxxxxxxxx"
export AWS_DEFAULT_REGION="ap-northeast-1"

Terraform will automatically detect them.

B. AWS CLI Credentials File (~/.aws/credentials)

• Run: aws configure
• Credentials file: ~/.aws/credentials

Example:
[default]
aws_access_key_id     = AKIAxxxxxxxxxxxx
aws_secret_access_key = xxxxxxxxxxxxxxxxx
region                = ap-northeast-1

Select profile if needed: export AWS_PROFILE=default

2. Bootstrap: Create S3 Bucket

cd bootstrap-s3
terraform init
terraform apply \
  -var="bucket_name=svc-plus-iac-state" \
  -var="region=ap-northeast-1"

This creates:

• S3 bucket for Terraform state
• Versioning enabled
• Server-side encryption (AES256) enabled

3. Bootstrap: Create DynamoDB Lock Table

cd bootstrap-dynamo-db
terraform init
terraform plan \
  -var="region=ap-northeast-1" \
  -var="table_name=svc-plus-iac-state-dynamodb-lock"
terraform apply \
  -var="region=ap-northeast-1" \
  -var="table_name=svc-plus-iac-state-dynamodb-lock"
terraform output

This creates:

• DynamoDB table: terraform-locks
• Primary key: LockID

PAY_PER_REQUEST billing mode Compatible with Terraform backend locking

4. Use in Terraform Backend

After both bootstrap steps are completed:

terraform { backend "s3" { bucket = "my-terraform-state" key = "envs/dev/terraform.tfstate" region = "ap-northeast-1" encrypt = true dynamodb_table = "terraform-locks" } }

Then run:

terraform init -migrate-state

5. Security Notes

Never store AWS credentials in Terraform variables Never commit credentials to Git

Prefer:

• environment variables
• AWS CLI profiles
• IAM Role / SSO / OIDC (recommended)
• S3 bucket has: Versioning ON

Server-side encryption ON

6. Cleanup

To remove bootstrap resources:

terraform destroy

Access Key + STS 的执行流程（内部机制）

你的 Terraform 执行流程变成：

Terraform 读取你的 Access Key → 用 GET CALLER IDENTITY 验证身份 调用 sts:AssumeRole 获得临时凭证（Session Token） Terraform 使用临时凭证执行所有资源创建

AccessKey → STS → AssumeRole → 临时 Token → Terraform apply