05(a)-Setup-virtual-network-using-Terraform.md

05(a)-Setup virtual network using Terraform

Learning Goals

The 5th exercise is designed to be deployed in two parts - in the first part you will set up the network configurations and in the second part you will deploy VMs using Terraform.

In this exercise, you will gain hands-on experience with Terraform to provision a virtual network in Azure.

Objective

• Create and configure a virtual network and subnets using Terraform.

Step-by-Step Instructions

• Go to the folder labs/05-Setup-VM-Using-Terraform/start. That is where your exercise files should be created.

Define Variables in variables.tf

We are going to define our variables seperately in a file. This will help in managing configurations effectively and maintaining modularity.

Some of the variables we are going to set are:

• exercise for prefixing some of our objects so they are easy to manage together
• admin_username and admin_password for setting up a user on the new VM's which you will provision in the next part of the exercise.
• source_image_reference for the image that the VM's are going to use for provisioning in the next part of the exercise.

Variable Declarations and Descriptions:

1. Go to the project directory:

   • Navigate to labs/05-Setup-VM-Using-Terraform/start where your exercise files should be created.

2. Create the variables.tf file:

   • Create a new file named variables.tf in the labs/05-Setup-VM-Using-Terraform/start directory.

3. Open the variables.tf file:

   • Open the file you just created (variables.tf).

4. Define the exercise variable:

   • This variable should be of type string.
   • It will be used to make the names of some resources unique.
   • Provide a description that explains its purpose.

5. Define the network variable:

   • This variable should be an object containing a property ranges (a list of strings)
   • Set a default value with a typical network range, for example, "10.0.0.0/16".
   • Provide a description that explains it is the virtual netwrok address range.

6. Define the client_subnet variable:

   • This variable should be an object with two properties: name (a string) and ranges (a list of strings).
   • Set default values for name and ranges (e.g., "client" and "10.0.0.0/24" respectively).
   • Provide a description that explains it is the subnet and address range for clients.

7. Define the server_subnet variable:

   • This variable should be an object with two properties: name (a string) and ranges (a list of strings).
   • Set default values for name and ranges (e.g., "server" and "10.0.3.0/24" respectively).
   • Provide a description that explains it is the subnet and address range for servers.

8. Define the admin_password variable:

   • This variable should be of type string.
   • Mark it as sensitive.
   • Provide a description that it is the default password to connect to the servers we deploy.

9. Define the admin_username variable:

   • This variable should be of type string.
   • Provide a description that it is the default admin user to connect to the servers we deploy.

10. Define the source_image_reference variable:

• This variable should be an object with four properties: publisher, offer, sku, and version (all strings).

• Set default values for each property:

  • publisher: Use "Canonical".
  • offer: Use "0001-com-ubuntu-server-jammy".
  • sku: Use "22_04-lts-gen2".
  • version: Use "latest".

• Provide a multi-line description explaining it is the SKU details for the image to be deployed.

  Example for object with properties that are lists of strings:

  To define a variable that is an object with properties that are lists of strings, you can use the object type with the appropriate property types. Consider this example:

variable "network" {
 type = object({
   ranges = list(string)
 })
 default = {
   ranges = [
     "192.0.0.0/16"
   ]
 }

 description = "virtual address range"
}

In this example, network is an object with a property ranges that is a list of string.

11. Save the variables.tf file:

• Ensure all your variable definitions are correctly formatted and saved.

Reference these variables in your future configurations using var.<variable_name> to dynamically configure resources based on defined values.

2. Set Values in _config.auto.tfvars

1. Create the config.auto.tfvars file:

   • In the same directory (labs/05-Setup-VM-Using-Terraform/start), create a new file named _config.auto.tfvars.

2. Declare variable values in _config.auto.tfvars:

   • Open config.auto.tfvars and add the following content to set values for the variables:

     exercise = "exercise5"
     
     server_subnet = {
       name = "server"
       ranges = [
         "10.0.1.0/24"
       ]
     }
     
     admin_password = "aflk89!nknvlknglkvgew"
     admin_username = "adminuser"

3. Save the _config.auto.tfvars file:

   • Ensure the values are correctly formatted and saved.

Checkpoint 1: Initialize Terraform

After defining your variables, initialize Terraform to ensure everything is set up correctly.

terraform init
terraform plan

This will ensure that your Terraform configuration is initialized and will allow you to verify that the variable setup is correct.

1. Introduction to Virtual Network Setup

A virtual network allows VMs and other resources to communicate with each other. Let's start with creating that.

2. Configure Network and Subnets

Creating 00_create_network.tf

This configuration sets up the virtual network and associated subnets. This is crucial as it forms the foundational network infrastructure in which the VMs will operate.

Task Instructions:

1. Go to the project directory:

   • Navigate to labs/05-Setup-VM-Using-Terraform/start where your exercise files should be created.

2. Create the 00_create_network.tf file:

   • Create a new file named 00_create_network.tf in the labs/05-Setup-VM-Using-Terraform/start directory.

3. Open the 00_create_network.tf file:

   • Open the file you just created (00_create_network.tf).

4. Start the Terraform Block:

   • Begin by adding an empty terraform {} block to indicate this file contains Terraform configuration.

     terraform {}

5. Define the Virtual Network Resource:

   • Add the azurerm_virtual_network resource block.
   • Set the resource name to exercise5.
   • Set the name property to "vnet-exercise5".
   • Set the resource_group_name property to data.azurerm_resource_group.studentrg.name.
   • Set the location property to data.azurerm_resource_group.studentrg.location.
   • Reference the address_space property to the variable you created earlier for network range like var.network.ranges.

6. Define the Client Subnet Resource:

   • Add the azurerm_subnet resource block for the client subnet.
   • Set the resource name to client.
   • Reference the name property to the variable you created earlier for client subnet name likevar.client_subnet.name.
   • Set the resource_group_name property to data.azurerm_resource_group.studentrg.name.
   • Set the virtual_network_name property to azurerm_virtual_network.exercise5.name.
   • Reference the address_prefixes to the variable you created earlier for client subnet ranges like var.client_subnet.ranges.

7. Define the Server Subnet Resource:

   • Add the azurerm_subnet resource block for the server subnet.
   • Set the resource name to server.
   • Refernece the name property to the variable you created earlier for server subnet name like var.server_subnet.name.
   • Set the resource_group_name property to data.azurerm_resource_group.studentrg.name.
   • Set the virtual_network_name property to azurerm_virtual_network.exercise5.name.
   • Reference the address_prefixes property to the variable you created earlier for server subnet range like var.server_subnet.ranges.

8. Save the 00_create_network.tf file:

   • Ensure all configurations are correctly formatted.
   • Save the file in the labs/05-Setup-VM-Using-Terraform/start directory.

Initialize Terraform, Plan and Apply Network Configuration

After defining the network and subnets, initialize Terraform again to make sure it's ready for the new resources and then validate your setup by running the following:

terraform init
terraform plan

If the plan looks correct, apply the configuration to create the network and subnets:

terraform apply

Congratulations 🎉 🎉

By completing this exercise, you've learned to set up and manage network configurations in Azure using Terraform, which is crucial for effective cloud infrastructure management.

Note: Do not destroy the resources yet.. you will need them for the next part of the exercise.