Terraform tigger a module after a resouce is created

user_17212864 0
Viewed 447

Very new to Terraform so give all the simple advice you got.

I want to setup a RKE-Cluster using/getting the Digital Ocean's newly created droplet IP address. I've setup a local_file to create a txt file in the RKE module (a real weird way to do it but not sure what else I can do.) When I try to terraform plan it I get

on modules/rke/rke.tf line 14, in data "template_file" "rkeip":
│   14:   template = file("${path.module}/rkeip.txt")
│     ├────────────────
│     │ path.module is "modules/rke"
│ 
│ Invalid value for "path" parameter: no file exists at modules/rke/rkeip.txt; this function works only with files
│ that are distributed as part of the configuration source code, so if this file will be created by a resource in
│ this configuration you must instead obtain this result from an attribute of that resource.

Here's what my droplet file looks like

 terraform {
  required_providers {
    digitalocean = {
      source = "digitalocean/digitalocean"
      version = "~> 2.0"
    }
  }
}

variable "do_token" {}
variable "ssh_key_name" {}

provider "digitalocean" {
  token = var.do_token
}

data "digitalocean_ssh_key" "default" {
  name = "${var.ssh_key_name}"
}
#this installs Docker
data "template_file" "cloud-yaml" {
  template = file("${path.module}/modules/cloud.yaml")
}

resource "digitalocean_droplet" "terra" {
  image  = "ubuntu-20-04-x64"
  name   = "terra"
  region = "sfo3"
  size   = "s-1vcpu-1gb"
  ssh_keys = ["${data.digitalocean_ssh_key.default.fingerprint}"]
  user_data = data.template_file.cloud-yaml.rendered
}

resource "local_file" "rkeip" {
    content  = "${digitalocean_droplet.terra.ipv4_address}"
    filename = "${path.module}/modules/rke/rkeip.txt"
}

module "RKE" {
    source = "./modules/rke/"
}

and my RKE module

terraform {
  required_providers {
    rke = {
      source  = "rancher/rke"
      version = "1.2.4"
    }
  }
}

data "template_file" "rkeip" {
  template = file("${path.module}/rkeip.txt")
}

provider "rke" {
  log_file = "rke_debug.log"
}

resource "rke_cluster" "test" {
   nodes {
     address = data.template_file.rkeip.rendered
     user    = "root"
     role    = ["controlplane", "etcd", "worker"]
     ssh_key = file("~/.ssh/id_rsa")
    }
}

I've tried to use depends_on in rke.tf and droplet.tf but still same error.

rke digital-ocean terraform
2 Answers

Alrighty it seems that Terraform's rke cannot be made via a droplet in a one-shot so I have decided to use Provisioners to deal with all the mini-steps so for folks in similar positions here's my added code in the droplet.tf.

resource "null_resource" "rke" {
  connection {
            host = "${digitalocean_droplet.terra.ipv4_address}"
            type = "ssh"
            user = "root"
            private_key = file("${path.module}/YOURDOKEY")
            agent = false
        }

    provisioner "file" {
    source      = "${path.module}/keys.sh"
    destination = "/root/keys.sh"
  }
  
  provisioner "remote-exec" {
    inline = [
    "chmod +x /root/keys.sh",
    "./keys.sh",
    "rm keys.sh",
    "wget https://github.com/rancher/rke/releases/download/v1.3.2/rke_linux-amd64",
    "mv rke_linux-amd64 rke",
    "chmod +x rke",
    "printf '%s\n' 'nodes:' '  - address:' '    user: root' '    docker_socket: /var/run/docker.sock' '    role:' '      - controlplane' '      - etcd' '      - worker' '    ssh_key_path: ~/.ssh/id_rsa' >cluster.yml",
    "myip=$(curl ifconfig.co)",
    "sed -i \"s/address:/address: $myip/\" cluster.yml",
    ]
  }
}

Unfortunately it throws an error if you try ./rke up in remote-exec so you have to run it in the droplet.

Also I made keys.sh to bypass errors in inline since it did not like the commands. If you managed to place these commands without any errors feel free to comment.

#!/bin/bash
# keys.sh
# create ssh keys without direct input
ssh-keygen -t rsa -b 4096 -N '' <<<$'\n'
# so the droplet can ssh itself
cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys
sed -i '/AllowTcpForwarding/d' /etc/ssh/sshd_config
echo "AllowTcpForwarding yes" >> /etc/ssh/sshd_config
# not needed but I wanted to see the output
grep AllowTcpForwarding /etc/ssh/sshd_config

this is to fix docker errors in rke.

user_172128640

Your RKE module has different capitalization than the "rke" directory in the path. Do you think that might have something to do with it?

resource "local_file" "rkeip" {
    content  = "${digitalocean_droplet.terra.ipv4_address}"
    filename = "${path.module}/modules/rke/rkeip.txt"
}

module "RKE" {
    source = "./modules/rke/"
}

I would go one step further and say that, if all you're doing is passing a value which the child module requires, pass it in as a variable. Creating static files to pass information is an IAC anti-pattern IMO.

Note that "depends_on" is meant to be used as a last resort, and should include notation about why such a work-around was required.

user_71121160
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