Terraform Tutorials: Templating in Terraform

In Terraform, the template process refers to the process of using a template engine to dynamically generate configuration files or values based on a set of input parameters.

Terraform supports various template engines, including Go’s text/template and html/template, as well as the Jinja2 template engine. These template engines enable you to write dynamic templates with placeholders for values that will be replaced by actual values at runtime.

The template process in Terraform involves the following steps:

  1. Define a template file: Create a template file with placeholders for the values that will be replaced at runtime.
  2. Define variables: Define input variables that will be used to replace the placeholders in the template file.
  3. Use the template engine: Use the templatefile() function or template_file data source to render the template and generate the final output.
  4. Use the output: Use the generated output in your Terraform configuration, such as passing it to a resource as a value.

The template process is useful for generating dynamic configuration files, such as cloud-init scripts, Kubernetes manifests, and shell scripts, among others. It enables you to generate configuration files based on the specific needs of your environment, without having to hard-code the values in your Terraform configuration.

Example – 1

Example 2

List 10 real use case where i can use Template template_file of Terrraform

  1. Cloud-init Configuration: You can use Terraform’s template_file data source to create cloud-init configuration files for your virtual machines or instances.
  2. Nginx Configuration: With template_file, you can create an Nginx configuration file to customize the web server based on your specific needs.
  3. DNS Records: Use template_file to create custom DNS records and add them to your DNS server configuration files.
  4. Configuration Files for Services: template_file can be used to generate configuration files for various services such as Apache, MySQL, Postgres, etc.
  5. SSL/TLS Certificates: You can use template_file to generate SSL/TLS certificate configuration files for various web servers.
  6. Bash Scripts: Use template_file to generate bash scripts to automate repetitive tasks such as backing up files or deploying code.
  7. User Data for EC2 Instances: With template_file, you can create EC2 instance user data scripts to configure your instances when they launch.
  8. Load Balancer Configuration: You can use template_file to create load balancer configuration files for services like AWS Elastic Load Balancer (ELB) or NGINX.
  9. Kubernetes Manifests: template_file can be used to create Kubernetes manifest files for deploying applications to a Kubernetes cluster.
  10. Database Configuration Files: Use template_file to generate database configuration files for various databases like MongoDB, Redis, Cassandra, etc.

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