TerraSnow Enterprise

Enables the deployment of terraform defined AWS resources from ServiceNow via Terraform Enterprise

Overview

This project contains a terraform template to deploy a Ngnix reverse proxied, Flask based endpoint that handles Gitlab Tag and Push events by creating a ServiceNow Terraform Module Catalog Item within your target ServieNow Catalog.

Additionally, this project enables ServiceNow to create a Terraform Enterprise workspace from the source terraform resource catalog item.

Requirements

• Pre-configured AWS account
• Latest version of terraform installed on your local machine
• Pre-configured Gitlab instance
• Pre-configured ServiceNow Instance
• Pre-configured Terraform Enterprise Instance
• Credentials of ServiceNow user with API access

How to Use

Deploy Terraform scripting instance

1. Create a terraform.tfvars file in the scripting_host folder and add your environment variables.
2. Deploy scripting host using terraform apply.
3. Grab the ssh public key using the URL providded in the pub_deployment_key output, so it can be added to GitLab.
4. Note the URL of the gitlab_webhook output.

Adding Terraform Modules to ServiceNow Catalog

Note: Module repositories must meet the same requirements as those outlined for addition to the Terraform Module Private Registry

1. Create a Gitlab repo with the terraform-<PROVIDER>-<MODULE_NAME> name format
2. Add the terraform scripting host (tfsh) url as a webhook under Repo > Settings > Integrations
   • Select Tag push events and Enable SSL verification
   • Click the Add Webhook button to complete
3. Add the terraform scripting host public key to the repo
4. Add a version tag to your project before commit that follows the PEP 440 standard (ex: 1.0.2)

Deploying Terraform Resources from ServiceNow

Setup

ServiceNow

• ServiceNow instance REST api account credentials

Terraform Enterprise

• Generate a USER oauth token
• Add Gitlab as a VCS in your Terraform Enterprise organization

Generate conf.ini

Create this file and upload it to an encrypted S3 bucket.

[SERVICENOW]
INSTANCE_NAME=
SN_API_USER_NAME=
SN_API_USER_PWD=

[TERRAFORM_ENTERPRISE]
INSTANCE_NAME=
ATLAS_TOKEN=

Scripting Host (Deploy it)

1. Clone this repo
2. Configure your local env to target the correct AWS account
3. Navigate to the scripting_host folder and create a terraform.tfvars file specific to your target AWS env
4. Run terraform apply

Gitlab

• Add the Scripting Host as an application in your gitlab account
• Add the Scripting Host's public key (available at https://yourscriptinghost/pub-key/key.txt) as a Deploy Key with read access

Workflow Overview

1. A Gitlab project is created for the source terraform module and associated with the webhook listener on tag update
2. When the webhook receives a tag update event it queries the target servicenow instance for a catalog item matching the project name and version number.

• if a catalog item is not found it creates a new one
• if a catalog item is found and the version is the same as the previous it takes no action

Documentation

For more information on installing and using TerraSnow Enterprise, go to https://terrasnow-enterprise.readthedocs.io