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docs/terraform/ansible-inventory-generation.md

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+# Generating a Ansible Inventory File from Terraform
+
+## Overview
+
+Often when working with automated deployments you will want to generate a dynamic inventory file for Ansible (usually after your infrastructure has been provisioned). This is a simple snippet to generate an inventory file from Terraform.
+
+## Terraform Snippet
+
+First we need to create an ouput variable to hold the inventory file.
+
+::: code-group
+
+```hcl [ouputs.tf]
+output "ansible_inventory_yml" {
+  description = "An Ansible inventory (in YAML format) containing IP addresses as required by the Ansible playbook to configure the servers."
+  value = local.ansible_inventory_yml
+}
+```
+
+:::
+
+Next we will create the local variable that will hold the inventory file.
+
+::: info
+
+In this example we are using a DigitalOcean droplet, but you can use any Terraform resource that has an IP address.
+
+:::
+
+::: code-group
+
+```hcl [locals.tf]
+locals {
+  ansible_inventory_yml = <<-EOF
+    all:
+      hosts:
+        app:
+          ansible_host: ${digitalocean_droplet.server.ipv4_address}
+  EOF
+}
+```
+
+:::
+
+::: tip
+
+It's better to use a local and output variable rather then a local_file as this avoids spurious plan noise when running on CI runners.
+
+:::
+
+Once all configured you can run `terraform apply` and the inventory file will be ouput to the console. To create the file you can pipe the output to a file (either in the console or in your CI pipeline).
+
+```bash
+terraform output -raw ansible_inventory_yml > ansible-inventory.yml
+```

docs/terraform/index.md

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+# Terraform Snippets and Musings
+
+#### [Generating a Ansible Inventory File from Terraform](./ansible-inventory-generation.md)