terraform-scripts

This repository holds our common Terraform Open edX deployment scripts. They can be used to provision and manage the infrastructure required by an Open edX instance on AWS.

Architecture map

See this document.

Conventions

Resource naming

Every resource provisioned by Terraform should be created using the following naming schema:

`{prefix}-{environment}-{resource}-{additional_info}`

prefix: name prefix for all the Terraform provisioned resources.
environment: stage, production, upgrade.
resource and additional_info: Defined by the modules when instancing resources.

Examples:

opencraftx-production-appserver-1 - Appserver from the production environment of client OpenCraftX
example-stage-alb - Alb resource for client Example

To ease the migration and import process, for resources where renaming implies changing credentials or replacement, a name override variable is available.

The variables that allow name overrides are detailed on each module, and should be named as following:

override_{resource_name}_name

Module categories & repo folder structure

The Terraform modules must be categorized in one of the following categories:

Core: used to provision a vanilla Open edX instance and it's required dependencies, such as S3 buckets, databases, load balancer, security groups, etc.
Optional: depend on resources provisioned by the core module and are used to automate parts of the provisioning that might change from a customer to another one, as well as deploy additional services and functionality to the platform. Examples of modules here are: DNS management, email provisioning, marketing websites, auto-scaling and analytics.

These categories dictate the directory a given module will live in:

# Main Open edX services are provisioned here
/modules/core/openedx

# Other modules should live here
/modules/optional/analytics
/modules/optional/marketing_site
/modules/optional/ses_email_setup

This folder structure serves two purposes:

Allow developers to easily differentiate between optional and core services to an Open edX instance.
Accomodate for differences in deployment types between clients without making modules unecessarily complex with toggles and settings.

State storage

The Terraform state file should be stored in a versioned and encrypted storage. Some acceptable options are listed below:

Legacy documentation

Currently it actually contains two different ways to provision AWS resources

First Approach

Everything inside the modules/openedx folder.

TODOS:

Explanation of how to use these modules
rds and s3 modules should be merged into the application module
Simplify configuration variables and remove most deprecated settings (check client requirements first)
Rename application to openedx and move wordpress to outside of the openedx directory
Automatically provision ACM certificates and domain names
Move VPC creation from private-repo to openedx module

Second Approach

Pretty basic way of provisioning, it contains the following modules:

modules/email
modules/route53
modules/s3
modules/services/director
modules/services/elasticsearch
modules/services/mongodb
modules/services/openedx
modules/services/sql
modules/services/analytics

Please check each of those module folders to see what the module does. For a simple AWS OpenedX provisioning, you could reuse these modules on the following way:

One Terraform project with you'll only need to setup once (Route53, email):

provider "aws" {
  region = <AWS Region>
  ...
}

module "route53" {
  source = "[email protected]:open-craft/terraform-scripts.git//modules/route53?ref=<LATEST RELEASE>"

  customer_domain = <CUSTOMER DOMAIN>
}

module "email" {
  source = "[email protected]:open-craft/terraform-scripts.git//modules/email?ref=<LATEST RELEASE>"

  customer_domain = <CUSTOMER DOMAIN>
  custom_emails_to_verify = <LIST OF EMAILS>
  internal_emails = <LIST OF INTERNAL EMAILS>
  route53_id = module.route53.route53_id

  customer_name = <CUSTOMER NAME>
  environment = <CUSTOMER ENVIRONMENT>
}

And another one for all the resources used in conjunction with the OpenedX instance:

provider "aws" {
  region = "<AWS Region>"
  ...
}

module "director" {
  source = "[email protected]:open-craft/terraform-scripts.git//modules/services/director?ref=<LATEST RELEASE>"
  director_key_pair_name = <AWS DIRECTOR KEY PAIR NAME>
  image_id = <AWS DIRECTOR IMAGE ID>
  instance_type = <AWS DIRECTOR INSTANCE TYPE>
}

module "s3" {
  source = "[email protected]:open-craft/terraform-scripts.git//modules/s3?ref=<LATEST RELEASE>"
  customer_name = <CUSTOMER NAME>
  environment = <CUSTOMER ENVIRONMENT>
}

module "openedx" {
  source = "[email protected]:open-craft/terraform-scripts.git//modules/services/openedx?ref=<LATEST RELEASE>"
  customer_name = <CUSTOMER NAME>
  director_security_group_id = module.director.director_security_group_id
  environment = <CUSTOMER ENVIRONMENT>
  customer_domain = <CUSTOMER DOMAIN>
}

module "sql" {
  source = "[email protected]:open-craft/terraform-scripts.git//modules/services/sql?ref=<LATEST RELEASE>"

  customer_name = <CUSTOMER NAME>
  environment = <CUSTOMER ENVIRONMENT>

  allocated_storage = <SQL ALLOCATED STORAGE>
  database_root_username = <SQL ROOT USERNAME>
  database_root_password = <SQL ROOT PASSWORD>

  edxapp_security_group_id = module.openedx.edxapp_security_group_id

  instance_class = <SQL INSTANCE CLASS>
}

module "elasticsearch" {
  source = "[email protected]:open-craft/terraform-scripts.git//modules/services/elasticsearch?ref=<LATEST RELEASE>"
  customer_name = <CUSTOMER NAME>
  edxapp_security_group_id = module.openedx.edxapp_security_group_id
  environment = <CUSTOMER ENVIRONMENT>
}

resource aws_instance edxapp {
  ami = <AWS EDX IMAGE ID>
  instance_type = <AWS EDX INSTANCE TYPE>
  vpc_security_group_ids = [module.openedx.edxapp_security_group_id]

  root_block_device {
    volume_size = 50        # setting only 50 GB for the edxapp disk space
    volume_type = "gp2"
  }

  key_name = <AWS EDX KEY PAIR NAME>

  tags = {
    Name = "edxapp-1"  # keep adding resources and change the name
  }
}

// adding the edx instance into the load balancer
resource aws_lb_target_group_attachment edxapp {
  target_group_arn = module.openedx.edxapp_lb_target_group_arn
  target_id = aws_instance.edxapp.id
  port = 80

  lifecycle {
    create_before_destroy = true
  }
}

// adding the edx instance into the main domain load balancer
resource aws_lb_target_group_attachment "edxapp_main_domain" {
  target_group_arn = module.openedx.edxapp_main_domain_lb_target_group_arn
  target_id = aws_instance.edxapp.id
  port = 80
}

For more information on how to deploy an OpenedX instance with Terraform, please go to our internal AWS terraform deployment tutorial

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