[SOLVED] transfer a file to a gcp vm using provisioner and connection terraform

Issue

the specification of compute_instance which i tried to connect with :

    resource "google_compute_address" "ip_address" {
      name = "ipv4-address"
    }

    resource "google_compute_instance" "controller" {
      name         = "controller"
      machine_type = "n1-standard-2"
      zone         = "us-central1-a"

      boot_disk {
        initialize_params {
          image = "ubuntu-os-cloud/ubuntu-2204-lts"  
        }
      }

      # Pour attribuer une adresse IP dans la plage CIDR : 100.100.20.0/24
      network_interface {
        subnetwork = google_compute_subnetwork.subnet.name
        network_ip = "10.100.20.3"
        access_config {
          nat_ip = google_compute_address.ip_address.address
        }
      }

      metadata_startup_script =  "./'${file("${path.module}/Config_Ansible.sh")}'" 
      
      connection {
        type        = "ssh"
        user        = "MSI"  # Remplacez par votre nom d'utilisateur SSH
        private_key = file("./key")  # Remplacez par le chemin de votre clé privée SSH
        host        = google_compute_address.ip_address.address
      }
      
      provisioner "file" {
        source      = "../Ansible_playbooks/Inventory_create.sh"
        destination = "/home/ubuntu/Inventory_create.sh"
      }

      tags = ["ansible"]

    }

the content of the file "/key" from sshkey gcp service, i think this is the problem. Because the error :

Error: file provisioner error
│
│   with google_compute_instance.controller,
│   on Creation_VM_GCP.tf line 158, in resource "google_compute_instance" "controller":
│  158:   provisioner "file" {
│
│ Failed to read ssh private key: no key found

i tried to connect to this machine and send a file from local to this vm, using provisioner and connection but it failed.

Solution

Private and public ssh keys should be generated on the local machine (here's an example: https://git-scm.com/book/en/v2/Git-on-the-Server-Generating-Your-SSH-Public-Key).

The private key stays on the local machine and you should make sure that no-one has access to it and that it is password-protected, while the public key should be copied to the Virtual Machine so that you can access the VM using private/public key.

If you use something like this

metadata = {
    ssh-keys = "your-ssh-username:${file("local_path/to/your/public-key-file")}"
    # alternatively:
    # ssh-keys = "your-ssh-username:content_of_public_key"
}

and

connection {
  type        = "ssh"
  user        = "your-ssh-username"
  private_key = file("local_path/to/your/private-key-file")
  host        = self.network_interface[0].access_config[0].nat_ip
}

Terraform will copy the public key to the VM in the file $USER/.ssh/authorized_keys. You can also copy the public key manually to $USER/.ssh/authorized_keys on the VM, just make sure that each key in authorized_keys takes exactly one line!

Check ssh-keys example in: https://cloud.google.com/compute/docs/metadata/predefined-metadata-keys

See also: https://cloud.google.com/compute/docs/instances/access-overview#ssh-access

But also check the content of the local file "./'${file("${path.module}/Config_Ansible.sh")}'", maybe this takes care of uoploading the public key?

Edit: you can also have Terraform create a private/public key pair, see: How to create an SSH key in Terraform?

Answered By - user2314737

Answer Checked By - Gilberto Lyons (WPSolving Admin)