Terraform AWS RDS Postgres

A Terraform module for deploying an RDS PostreSQL instance in AWS.

The AWS RDS requires:

• An existing VPC

The RDS consists of:

• security groups
• subnet groups

Usage

To use the module, include something like the following in your Terraform configuration:

module "database" {
  source = "infrablocks/rds-postgres/aws"
  version = "0.1.8"

  region = "eu-west-2"
  vpc_id = "vpc-b197da6b"
  private_subnet_ids = "subnet-7cd8832a,subnet-0199db7c"
  private_network_cidr = "10.0.0.0/16"

  component = "identity-server"
  deployment_identifier = "2f3eddcb"

  database_instance_class = "db.t2.medium"
  database_version = "9.6.8"

  database_name = "identity"
  database_master_user = "admin"
  database_master_password = "1D$£#J!LKeE£(9d9"
}

As mentioned above, the database deploys into an existing base network:

• AWS Base Networking

See the Terraform registry entry for more details.

Inputs

Name	Description	Default	Required
region	The region into which to deploy the database	-	yes
vpc_id	The ID of the VPC into which to deploy the database	-	yes
component	The component this database will serve	-	yes
deployment_identifier	An identifier for this instantiation	-	yes
private_network_cidr	The CIDR of the private network allowed access to the ELB	-	yes
private_subnet_ids	The IDs of the private subnets to deploy the database into	-	yes
database_instance_class	The instance type of the RDS instance.	-	yes
database_version	The database version. If omitted, it lets Amazon decide.	-	no
database_name	The DB name to create. If omitted, no database is created initially.	-	yes
database_master_user_password	The password for the master database user.	-	yes
database_master_user	The username for the master database user.	-	yes
use_multiple_availability_zones	Whether to create a multi-availability zone database ("yes" or "no").	"no"	yes
use_encrypted_storage	Whether or not to use encrypted storage for the database ("yes" or "no").	"no"	yes
snapshot_identifier	The identifier of the snapshot to use to create the database.	-	no
backup_retention_period	The number of days to retain database backups.	7	yes
backup_window	The time window in which backups should take place.	"01:00-03:00"	yes
maintenance_window	The time window in which maintenance should take place.	"mon:03:01-mon:05:00"	yes
include_self_ingress_rule	Whether or not to add a self-referencing ingress rule on the security group	"no"	no
allow_major_version_upgrade	Whether or not to allow major version upgrades	"no"	no
auto_minor_version_upgrade	Whether or not to enable auto minor version upgrades	"yes"	no
storage_type	The storage type of the RDS instance ("standard" or "gp2")	"standard"	no
performance_insights_enabled	Whether or not performance insights are enabled	"no"	no
max_allocated_storage	When configured, the upper limit to which Amazon RDS can automatically scale the storage of the DB instance. See the terraform documentation for more information.	0	no

Outputs

Name	Description
postgres_database_port	The database port
postgres_database_host	The database host
postgres_database_name	The database name
postgres_database_sg_id	The database security group id

Compatibility

This module is compatible with Terraform versions greater than or equal to Terraform 1.0.

Development

Machine Requirements

In order for the build to run correctly, a few tools will need to be installed on your development machine:

• Ruby (3.1.1)
• Bundler
• git
• git-crypt
• gnupg
• direnv
• aws-vault

Mac OS X Setup

Installing the required tools is best managed by homebrew.

To install homebrew:

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

Then, to install the required tools:

# ruby
brew install rbenv
brew install ruby-build
echo 'eval "$(rbenv init - bash)"' >> ~/.bash_profile
echo 'eval "$(rbenv init - zsh)"' >> ~/.zshrc
eval "$(rbenv init -)"
rbenv install 3.1.1
rbenv rehash
rbenv local 3.1.1
gem install bundler

# git, git-crypt, gnupg
brew install git
brew install git-crypt
brew install gnupg

# aws-vault
brew cask install

# direnv
brew install direnv
echo "$(direnv hook bash)" >> ~/.bash_profile
echo "$(direnv hook zsh)" >> ~/.zshrc
eval "$(direnv hook $SHELL)"

direnv allow <repository-directory>

Running the build

Running the build requires an AWS account and AWS credentials. You are free to configure credentials however you like as long as an access key ID and secret access key are available. These instructions utilise aws-vault which makes credential management easy and secure.

To provision module infrastructure, run tests and then destroy that infrastructure, execute:

aws-vault exec <profile> -- ./go

To provision the module prerequisites:

aws-vault exec <profile> -- ./go deployment:prerequisites:provision[<deployment_identifier>]

To provision the module contents:

aws-vault exec <profile> -- ./go deployment:root:provision[<deployment_identifier>]

To destroy the module contents:

aws-vault exec <profile> -- ./go deployment:root:destroy[<deployment_identifier>]

To destroy the module prerequisites:

aws-vault exec <profile> -- ./go deployment:prerequisites:destroy[<deployment_identifier>]

Configuration parameters can be overridden via environment variables:

DEPLOYMENT_IDENTIFIER=testing aws-vault exec <profile> -- ./go

When a deployment identifier is provided via an environment variable, infrastructure will not be destroyed at the end of test execution. This can be useful during development to avoid lengthy provision and destroy cycles.

By default, providers will be downloaded for each terraform execution. To cache providers between calls:

TF_PLUGIN_CACHE_DIR="$HOME/.terraform.d/plugin-cache" aws-vault exec <profile> -- ./go

Common Tasks

Generating an SSH key pair

To generate an SSH key pair:

ssh-keygen -m PEM -t rsa -b 4096 -C [email protected] -N '' -f config/secrets/keys/bastion/ssh

Generating a self-signed certificate

To generate a self signed certificate:

openssl req -x509 -newkey rsa:4096 -keyout key.pem -out cert.pem -days 365

To decrypt the resulting key:

openssl rsa -in key.pem -out ssl.key

Add a git-crypt user

To adding a user to git-crypt using their GPG key:

gpg --import ~/path/xxxx.pub
git-crypt add-gpg-user --trusted GPG-USER-ID

Managing CircleCI keys

To encrypt a GPG key for use by CircleCI:

openssl aes-256-cbc \
  -e \
  -md sha1 \
  -in ./config/secrets/ci/gpg.private \
  -out ./.circleci/gpg.private.enc \
  -k "<passphrase>"

To check decryption is working correctly:

openssl aes-256-cbc \
  -d \
  -md sha1 \
  -in ./.circleci/gpg.private.enc \
  -k "<passphrase>"

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/infrablocks/terraform-aws-rds-postgres. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The library is available as open source under the terms of the MIT License.