@Chad thanks for writing back! Attached is the collect-logs output. 

For terraform, we're using a provider to hook into our proxmox infrastructure. Under the hood, proxmox is calling QEMU to manage the virtual machines. I installed `qemu-guest-agent` to the cloud-init image using `virt-customize` from the `libguestfs-tools` package.  

On first boot, the hostname is successfully set, but it doesn't appear to be fast enough before networking is brought up. 

To build an identical image to the one i'm using:
Download the cloudinit image 
```
wget https://cloud-images.ubuntu.com/focal/current/focal-server-cloudimg-amd64.img
```

use `virt-customize` to install `qemu-guest-agent`
```
sudo virt-customize -a https://cloud-images.ubuntu.com/focal/current/focal-server-cloudimg-amd64.img --install qemu-guest-agent
```

From there, we upload it to proxmox and have it clone the image for VM's. I would imagine if one used regular Qemu or another provider with terraform the behavior would be the same.  

Here's the output of `terraform apply`
```
module.greeks["attis"].proxmox_vm_qemu.basic_admin: Refreshing state... [id=aramis5/qemu/111]
 
Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following symbols:
  + create

Terraform will perform the following actions:

  # module.greeks["attis"].proxmox_vm_qemu.basic_admin will be created
  + resource "proxmox_vm_qemu" "basic_admin" {
      + additional_wait           = 0
      + agent                     = 1
      + automatic_reboot          = true
      + balloon                   = 0
      + bios                      = "seabios"
      + boot                      = "c"
      + bootdisk                  = "scsi0"
      + ciuser                    = "awx"
      + clone                     = "ubuntu-2004-cloudinit-terraform"
      + clone_wait                = 0
      + cores                     = 4
      + cpu                       = "host"
      + default_ipv4_address      = (known after apply)
      + define_connection_info    = true
      + force_create              = false
      + full_clone                = true
      + guest_agent_ready_timeout = 100
      + hotplug                   = "network,disk,usb"
      + id                        = (known after apply)
      + ipconfig0                 = "ip=dhcp"
      + kvm                       = true
      + memory                    = 8192
      + name                      = "attis"
      + nameserver                = (known after apply)
      + numa                      = false
      + onboot                    = false
      + oncreate                  = true
      + os_type                   = "cloud-init"
      + preprovision              = true
      + reboot_required           = (known after apply)
      + scsihw                    = "virtio-scsi-pci"
      + searchdomain              = (known after apply)
      + sockets                   = 1
      + ssh_host                  = (known after apply)
      + ssh_port                  = (known after apply)
      + sshkeys                   = "<trimmed>"
      + tablet                    = true
      + target_node               = "aramis5"
      + unused_disk               = (known after apply)
      + vcpus                     = 0
      + vlan                      = -1
      + vmid                      = (known after apply)

      + disk {
          + backup       = 0
          + cache        = "none"
          + discard      = "on"
          + file         = (known after apply)
          + format       = (known after apply)
          + iothread     = 0
          + mbps         = 0
          + mbps_rd      = 0
          + mbps_rd_max  = 0
          + mbps_wr      = 0
          + mbps_wr_max  = 0
          + media        = (known after apply)
          + replicate    = 0
          + size         = "32G"
          + slot         = 0
          + ssd          = 0
          + storage      = "ceph-external"
          + storage_type = (known after apply)
          + type         = "scsi"
          + volume       = (known after apply)
        }

      + network {
          + bridge    = "vmbr0"
          + firewall  = false
          + link_down = false
          + macaddr   = (known after apply)
          + model     = "virtio"
          + queues    = (known after apply)
          + rate      = (known after apply)
          + tag       = -1
        }
    }
```

`attis` is the desired hostname that we want for this particular machine