EWC - Create a new VM using Terraform or OpenTofu

This page describes how to create a new VM by using Terraform or OpenTofu.

Pre-requisites

The following pre-requisites must be satisfied.

• Have read and followed the EWC - IaC via Terraform and OpenTofu page.
• The Terraform or OpenTofu CLI installed. 
• Application credentials to access the Openstack cloud project

There is a set of mandatory inputs required to create a new VM which are:

• image_name  :  the Virtual Machine image (see EWC - VM images and default users )
• flavor_name  :  the resources (CPU, RAM, Disk) configuration for the VM (see as reference EWC VM plans )
• key_pair  :  configured SSH key which is needed to connect to the VM (see EWC - OpenStack Command-Line client for how to import it ) 
• security_groups : security groups are sets of applied IP filter rules which define networking access to the instance 
• network  : the network to be attached to the VM : external-internet: access to the Internet with public IP ; private-<tenant>: local private network within the tenant.

The available selectable options could also be checked using the Opnstack CLI commands :

$ openstack keypair list
 
$ openstack image list
 
$ openstack flavor list 
 
$ openstack network list

Write configuration files

Create a directory for your configuration and change directory into it:

$ mkdir example-create-vm

$ cd example-create-vm

Create the main configuration file to define the infrastructure:

$ touch main.tf

Open the main.tf file in a text editor and fill it as needed like in the following example :

# Define required providers
terraform {
required_version = ">= 0.14.0"
  required_providers {
    openstack = {
      source  = "terraform-provider-openstack/openstack"
      version = "~> 1.53.0"
    }
  }
}

# Configure the OpenStack Provider
provider "openstack" {
  # ...
}


resource "openstack_compute_instance_v2" "server-name" {
  name            = "server-name"
  image_name      = "image-name"
  flavor_name     = "flavor-name"
  key_pair        = "key-name"
  security_groups = ["secgroup-name-1", "secgroup-name-2", ...]

  network {
    name = "network-name"
  }
}

Replace the following fields as desired:

• server-name
• image-name
• flavor-name
• key-name
• secgroup-name-1 , secgroup-name-2
• network-name

For instance for ECMWF can be :

resource "openstack_compute_instance_v2" "test-server" {
  name            = "test-server"
  image_name      = "Rocky-9.4-20240717094419"
  flavor_name     = "2cpu-2gbmem-30gbdisk"
  key_pair        = "mykey"
  security_groups = ["default", "ssh"]

  network {
    name = "private-cci1-ewcloud-ms-nmhs-project"
  }
}

Run Terraform or OpenTofu to create a VM

Initialize the directory :

$ terraform init

$ tofu init

Review the required changes: 

$ terraform plan

Apply the changes to create the VM :

$ terraform apply

$ tofu apply

Status can be then seen via:

$ terraform show

$ tofu show

Destroy the VM

The created VM can be then destroyed by simply running:

$ terraform destroy

$ tofu destroy