How to add optional 2nd disk?

[LucEast]

Hello.

I use this provider to create cloud-init vm's as the following:

.
├── README.md
├── main.tf
├── modules
│   ├── cloud-init
│   │   └── cloud-init-files
│   └── vms
│       ├── cloud-init-template.yaml
│       ├── main.tf
│       └── variables.tf
└── variables.tf

I define the vm's as modules within the main.tf.
E.g.:

main.tf

terraform {
  required_providers {
    proxmox = {
      source  = "Telmate/proxmox"
      version = "3.0.1-rc3"
    }
  }
}

provider "proxmox" {
  pm_api_url          = var.pm_api_url
  pm_api_token_id     = var.pm_api_token_id
  pm_api_token_secret = var.pm_api_token_secret
  pm_tls_insecure     = true
}

module "harbor" {
  source          = "./modules/vms"
  hostname        = "harbor"
  ip_address      = "192.168.1.10/24"
  cores           = 2
  memory          = 4096
  sockets         = 1
  disk_size       = "40G"
  agent           = var.agent
  pve_host        = var.pve_host
  pve_user        = var.pve_user
  pve_private_key = var.pve_private_key
  protection      = true
  onboot          = true
}

modules/vms/main.tf

terraform {
  required_providers {
    proxmox = {
      source  = "Telmate/proxmox"
      version = "3.0.1-rc3"
    }
  }
}

resource "local_file" "cloud_init_config" {
  content = templatefile("${path.module}/cloud-init-template.yaml", {
    hostname   = var.hostname,
    ip_address = var.ip_address,
    gateway    = var.gateway,
    dns1       = var.dns1,
    dns_search = var.dns_search
  })
  filename = "${path.module}/cloud-init-${var.hostname}.yaml"
}

resource "null_resource" "cloud_init_config_files" {
  connection {
    type        = "ssh"
    user        = var.pve_user
    private_key = file(var.pve_private_key)
    host        = var.pve_host
  }

  provisioner "file" {
    source      = local_file.cloud_init_config.filename
    destination = "/tmp/user_data_vm-${var.hostname}.yaml"
  }

  provisioner "remote-exec" {
    inline = [
      "sudo mv /tmp/user_data_vm-${var.hostname}.yaml /var/lib/vz/snippets/user_data_vm-${var.hostname}.yaml",
      "sudo chown root:root /var/lib/vz/snippets/user_data_vm-${var.hostname}.yaml"
    ]
  }
}

resource "proxmox_vm_qemu" "vm" {
  name        = var.hostname
  target_node = var.target_node
  clone       = var.template_name
  full_clone  = var.full_clone
  agent       = var.agent

  # VM resources
  cores   = var.cores
  cpu     = var.cpu
  memory  = var.memory
  sockets = var.sockets

  # Network configuration

  ipconfig0    = "ip=${var.ip_address},gw=${var.gateway}"
  nameserver   = var.dns1
  searchdomain = var.dns_search

  # Cloud-Init settings
  cicustom = "user=local:snippets/user_data_vm-${var.hostname}.yaml"

  # Disk settings
  disks {
    scsi {
      scsi0 {
        disk {
          size    = var.disk_size
          storage = var.disk_storage
        }
      }
    }
    ide {
      ide2 {
        cloudinit {
          storage = var.disk_storage
        }
      }
    }
  }

  scsihw = var.scsihw

  # Network settings
  network {
    model  = var.network_model
    bridge = var.network_bridge
  }

  protection = var.protection

  kvm     = true
  balloon = 0

  # Start VM after creation
  vm_state = var.vm_state

  onboot = var.onboot
}

I now try to add an optional 2nd scsi disk for kubernetes downstream nodes but don't know how to make it truely optional.
My idea was, that it only get created when I specify a disk_size2 within the module.

Kind regards
Lucas

[julienym]

Good question! With the older disk {} way it was easy with dynamic block, exemple here: https://github.com/julienym/myTerraformModules/blob/2.1.1/proxmox/main.tf#L21

But now if you import a VM, it will by default use the new disks {} which I don't see how can be used dynamically

[Tinyblargon]

@julienym when the disk block is specified it takes priority over the disks block. disk is for modules and doesn't diff as neatly, disks is for direct configuration and the diff is exa4as expected. You can make a dynamic module around disks but that would require a lot of code in the module.

[julienym]

@Tinyblargon I just check and unless the provider resource block 'disks' is configured to use labels, I don't think it's possible to be use with dynamic_block. ref. https://kodekloud.com/blog/terraform-dynamic-block/
Therefore it would be hard to make any module to create a VM with diff. disk setup - aka based on variables. Having a TF resource per VM is then the only way? :(

[StoffelCPR]

Any news on this? I have the same problem. and wanted to post my own discussion, appending my question text:

Introduction

Hello together,

I'm struggling with something and I can't find a solution in the documentation nor can ChatGPT.

I've written my own module to generate virtualmachines inside a Proxmox cluster.

Code basis

resource "proxmox_vm_qemu" "virtualmachine" {
  name        = var.vm_name
  desc        = var.vm_description
  target_node = var.target_node
  vmid        = var.vm_id

  clone = var.clone_vm_name
  agent = var.agent
  pool  = var.pool

  os_type = var.os_name
  cores   = var.cores
  sockets = var.sockets
  memory  = var.memory
  balloon = var.memory
  tags    = var.tags

  scsihw = var.scsihw

  disks {
    ide {
      dynamic "ide3" {
        for_each = var.cloudinit == true ? [1] : []
        content {
          cloudinit {
            storage = var.storage
          }
        }
      }
    }
    scsi {
      scsi0 {
        disk {
          size    = var.main_disk_size
          storage = var.storage
        }
      }
    }
  }

  network {
    bridge   = var.bridge
    model    = "virtio"
    firewall = var.firewall
    tag      = var.network_tag
  }

  ipconfig0 = var.ipconfig0
  ciuser    = var.ciuser
  cipassword = var.cipassword
  sshkeys   = var.ssh_keys

  boot = "order=scsi0"
}

My question is about the disks{}

I have my main disk and a possible cloudinit disk set up for all VMs. They will always be the same.

Some VMs will receive multiple disks for LVM encryption so I need to generate these.

Question

Can I somehow generate additional SCSI disks here with tofu code that depend on a variable?

e.g.

variable "additional_disks" {
  description = "List of additional disks to be attached to the VM"
  type        = list(object({
    size     = string
    storage  = string
  }))
  default     = []
}

With this variable I'd like to have scsi1, scsi2 and scsi3 generated if they're present in the additional_disks variable.

Any ideas?