terraform-aws-tfstate-backend

Terraform module to provision an S3 bucket to store terraform.tfstate file and a DynamoDB table to lock the state file to prevent concurrent modifications and state corruption.

The module supports the following:

1. Forced server-side encryption at rest for the S3 bucket
2. S3 bucket versioning to allow for Terraform state recovery in the case of accidental deletions and human errors
3. State locking and consistency checking via DynamoDB table to prevent concurrent operations
4. DynamoDB server-side encryption

https://www.terraform.io/docs/backends/types/s3.html

NOTE: The operators of the module (IAM Users) must have permissions to create S3 buckets and DynamoDB tables when performing terraform plan and terraform apply

NOTE: This module cannot be used to apply changes to the mfa_delete feature of the bucket. Changes regarding mfa_delete can only be made manually using the root credentials with MFA of the AWS Account where the bucket resides. Please see: hashicorp/terraform-provider-aws#62

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It's 100% Open Source and licensed under the APACHE2.

We literally have hundreds of terraform modules that are Open Source and well-maintained. Check them out!

Security & Compliance

Security scanning is graciously provided by Bridgecrew. Bridgecrew is the leading fully hosted, cloud-native solution providing continuous Terraform security and compliance.

Benchmark	Description
	Infrastructure Security Compliance
	Center for Internet Security, KUBERNETES Compliance
	Center for Internet Security, AWS Compliance
	Center for Internet Security, AZURE Compliance
	Payment Card Industry Data Security Standards Compliance
	National Institute of Standards and Technology Compliance
	Information Security Management System, ISO/IEC 27001 Compliance
	Service Organization Control 2 Compliance
	Center for Internet Security, GCP Compliance
	Health Insurance Portability and Accountability Compliance

Usage

IMPORTANT: We do not pin modules to versions in our examples because of the difficulty of keeping the versions in the documentation in sync with the latest released versions. We highly recommend that in your code you pin the version to the exact version you are using so that your infrastructure remains stable, and update versions in a systematic way so that they do not catch you by surprise.

Also, because of a bug in the Terraform registry (hashicorp/terraform#21417), the registry shows many of our inputs as required when in fact they are optional. The table below correctly indicates which inputs are required.

Create

Follow this procedure just once to create your deployment.

1. Add the terraform_state_backend module to your main.tf file. The comment will help you remember to follow this procedure in the future:

    # You cannot create a new backend by simply defining this and then
    # immediately proceeding to "terraform apply". The S3 backend must
    # be bootstrapped according to the simple yet essential procedure in
    # https://github.com/cloudposse/terraform-aws-tfstate-backend#usage
    module "terraform_state_backend" {
      source = "cloudposse/tfstate-backend/aws"
      # Cloud Posse recommends pinning every module to a specific version
      # version     = "x.x.x"
      namespace  = "eg"
      stage      = "test"
      name       = "terraform"
      attributes = ["state"]
   
      terraform_backend_config_file_path = "."
      terraform_backend_config_file_name = "backend.tf"
      force_destroy                      = false
    }
   
    # Your Terraform configuration
    module "another_module" {
      source = "....."
    }

   Module inputs terraform_backend_config_file_path and terraform_backend_config_file_name control the name of the backend definition file. Note that when terraform_backend_config_file_path is empty (the default), no file is created.

2. terraform init. This downloads Terraform modules and providers.

3. terraform apply -auto-approve. This creates the state bucket and DynamoDB locking table, along with anything else you have defined in your *.tf file(s). At this point, the Terraform state is still stored locally.

   Module terraform_state_backend also creates a new backend.tf file that defines the S3 state backend. For example:

    backend "s3" {
      region         = "us-east-1"
      bucket         = "< the name of the S3 state bucket >"
      key            = "terraform.tfstate"
      dynamodb_table = "< the name of the DynamoDB locking table >"
      profile        = ""
      role_arn       = ""
      encrypt        = true
    }

   Henceforth, Terraform will also read this newly-created backend definition file.

4. terraform init -force-copy. Terraform detects that you want to move your Terraform state to the S3 backend, and it does so per -auto-approve. Now the state is stored in the S3 bucket, and the DynamoDB table will be used to lock the state to prevent concurrent modification.

This concludes the one-time preparation. Now you can extend and modify your Terraform configuration as usual.

Destroy

Follow this procedure to delete your deployment.

1. In main.tf, change the terraform_state_backend module arguments as follows:

    module "terraform_state_backend" {
        ...
      terraform_backend_config_file_path = ""
      force_destroy                      = true
    }

2. terraform apply -target module.terraform_state_backend -auto-approve. This implements the above modifications by deleting the backend.tf file and enabling deletion of the S3 state bucket.
3. terraform init -force-copy. Terraform detects that you want to move your Terraform state from the S3 backend to local files, and it does so per -auto-approve. Now the state is once again stored locally and the S3 state bucket can be safely deleted.
4. terraform destroy. This deletes all resources in your deployment.
5. Examine local state file terraform.tfstate to verify that it contains no resources.

Bucket Replication (Disaster Recovery)

To enable S3 bucket replication in this module, set s3_replication_enabled to true and populate s3_replica_bucket_arn with the ARN of an existing bucket.

 module "terraform_state_backend" {
   source = "cloudposse/tfstate-backend/aws"
   # Cloud Posse recommends pinning every module to a specific version
   # version     = "x.x.x"
   namespace  = "eg"
   stage      = "test"
   name       = "terraform"
   attributes = ["state"]

   terraform_backend_config_file_path = "."
   terraform_backend_config_file_name = "backend.tf"
   force_destroy                      = false

   s3_replication_enabled = true
   s3_replica_bucket_arn  = "arn:aws:s3:::eg-test-terraform-tfstate-replica"
 }

Makefile Targets

Available targets:

  help                                Help screen
  help/all                            Display help for all targets
  help/short                          This help short screen
  lint                                Lint terraform code

Requirements

Name	Version
terraform	>= 0.13.0
aws	>= 2.0
local	>= 1.3
template	>= 2.0

Providers

Name	Version
aws	>= 2.0
local	>= 1.3
template	>= 2.0

Inputs

Name	Description	Type	Default	Required
acl	The canned ACL to apply to the S3 bucket	string	"private"	no
additional_tag_map	Additional tags for appending to tags_as_list_of_maps. Not added to tags.	map(string)	{}	no
arn_format	ARN format to be used. May be changed to support deployment in GovCloud/China regions.	string	"arn:aws"	no
attributes	Additional attributes (e.g. 1)	list(string)	[]	no
billing_mode	DynamoDB billing mode	string	"PROVISIONED"	no
block_public_acls	Whether Amazon S3 should block public ACLs for this bucket	bool	true	no
block_public_policy	Whether Amazon S3 should block public bucket policies for this bucket	bool	true	no
context	Single object for setting entire context at once. See description of individual variables for details. Leave string and numeric variables as null to use default value. Individual variable settings (non-null) override settings in context object, except for attributes, tags, and additional_tag_map, which are merged.	any	{ "additional_tag_map": {}, "attributes": [], "delimiter": null, "enabled": true, "environment": null, "id_length_limit": null, "label_key_case": null, "label_order": [], "label_value_case": null, "name": null, "namespace": null, "regex_replace_chars": null, "stage": null, "tags": {} }	no
delimiter	Delimiter to be used between namespace, environment, stage, name and attributes. Defaults to - (hyphen). Set to "" to use no delimiter at all.	string	null	no
enable_point_in_time_recovery	Enable DynamoDB point-in-time recovery	bool	true	no
enable_public_access_block	Enable Bucket Public Access Block	bool	true	no
enable_server_side_encryption	Enable DynamoDB server-side encryption	bool	true	no
enabled	Set to false to prevent the module from creating any resources	bool	null	no
environment	Environment, e.g. 'uw2', 'us-west-2', OR 'prod', 'staging', 'dev', 'UAT'	string	null	no
force_destroy	A boolean that indicates the S3 bucket can be destroyed even if it contains objects. These objects are not recoverable	bool	false	no
id_length_limit	Limit id to this many characters (minimum 6). Set to 0 for unlimited length. Set to null for default, which is 0. Does not affect id_full.	number	null	no
ignore_public_acls	Whether Amazon S3 should ignore public ACLs for this bucket	bool	true	no
label_key_case	The letter case of label keys (tag names) (i.e. name, namespace, environment, stage, attributes) to use in tags. Possible values: lower, title, upper. Default value: title.	string	null	no
label_order	The naming order of the id output and Name tag. Defaults to ["namespace", "environment", "stage", "name", "attributes"]. You can omit any of the 5 elements, but at least one must be present.	list(string)	null	no
label_value_case	The letter case of output label values (also used in tags and id). Possible values: lower, title, upper and none (no transformation). Default value: lower.	string	null	no
logging	Bucket access logging configuration.	object({ bucket_name = string prefix = string })	null	no
mfa_delete	A boolean that indicates that versions of S3 objects can only be deleted with MFA. ( Terraform cannot apply changes of this value; hashicorp/terraform-provider-aws#629 )	bool	false	no
name	Solution name, e.g. 'app' or 'jenkins'	string	null	no
namespace	Namespace, which could be your organization name or abbreviation, e.g. 'eg' or 'cp'	string	null	no
prevent_unencrypted_uploads	Prevent uploads of unencrypted objects to S3	bool	true	no
profile	AWS profile name as set in the shared credentials file	string	""	no
read_capacity	DynamoDB read capacity units	number	5	no
regex_replace_chars	Regex to replace chars with empty string in namespace, environment, stage and name. If not set, "/[^a-zA-Z0-9-]/" is used to remove all characters other than hyphens, letters and digits.	string	null	no
restrict_public_buckets	Whether Amazon S3 should restrict public bucket policies for this bucket	bool	true	no
role_arn	The role to be assumed	string	""	no
s3_bucket_name	S3 bucket name. If not provided, the name will be generated by the label module in the format namespace-stage-name	string	""	no
s3_replica_bucket_arn	The ARN of the S3 replica bucket (destination)	string	""	no
s3_replication_enabled	Set this to true and specify s3_replica_bucket_arn to enable replication	bool	false	no
stage	Stage, e.g. 'prod', 'staging', 'dev', OR 'source', 'build', 'test', 'deploy', 'release'	string	null	no
tags	Additional tags (e.g. map('BusinessUnit','XYZ')	map(string)	{}	no
terraform_backend_config_file_name	Name of terraform backend config file	string	"terraform.tf"	no
terraform_backend_config_file_path	Directory for the terraform backend config file, usually .. The default is to create no file.	string	""	no
terraform_backend_config_template_file	The path to the template used to generate the config file	string	""	no
terraform_state_file	The path to the state file inside the bucket	string	"terraform.tfstate"	no
terraform_version	The minimum required terraform version	string	"0.12.2"	no
write_capacity	DynamoDB write capacity units	number	5	no

Outputs

Name	Description
dynamodb_table_arn	DynamoDB table ARN
dynamodb_table_id	DynamoDB table ID
dynamodb_table_name	DynamoDB table name
s3_bucket_arn	S3 bucket ARN
s3_bucket_domain_name	S3 bucket domain name
s3_bucket_id	S3 bucket ID
terraform_backend_config	Rendered Terraform backend config file

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Related Projects

Check out these related projects.

• terraform-aws-dynamodb - Terraform module that implements AWS DynamoDB with support for AutoScaling
• terraform-aws-dynamodb-autoscaler - Terraform module to provision DynamoDB autoscaler

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Andriy Knysh	Erik Osterman	Maarten van der Hoef	Vladimir	Chris Weyl	John McGehee	Oliver L Schoenborn