terraform-configs

Various configuration files for terraform.

Terraform is infrastructure as code. It's not meant to interact with cloud providers to query and set account information in the same way that doctl, aws, or Az does. It uses your account authorization to build infrastructure.

Install terraform

Validate your install with one of these public keys:

• hashicorp public keys C874 011F 0AB4 0511 0D02 1055 3436 5D94 72D7 468F
• hashicorp public keys on keybase.io C874 011F 0AB4 0511 0D02 1055 3436 5D94 72D7 468F
• [hashicorp gpg apt key]https://apt.releases.hashicorp.com/gpg) 798A EC65 4E5C 1542 8C8E 42EE AA16 FCBC A621 E701

The CLI tool can be installed via apt.

• terraform CLI tool

Ubuntu/Debian install:

wget -O- https://apt.releases.hashicorp.com/gpg | sudo gpg --dearmor -o /usr/share/keyrings/hashicorp-archive-keyring.gpg
echo "deb [signed-by=/usr/share/keyrings/hashicorp-archive-keyring.gpg] https://apt.releases.hashicorp.com $(lsb_release -cs) main" | sudo tee /etc/apt/sources.list.d/hashicorp.list
sudo apt update && sudo apt install terraform

Platform Requirements

terraform: Azure

• terraform + Azure
  • Az PowerShell Module

terraform: Digital Ocean

• terraform + Digital Ocean
• You need a (usually 90 day) personal access token. Save it to your credential manager, as it's only shown during creation
• When using a Yubikey + GPG for SSH, the var.pvt_key variable should be commented out, and replaced with agent = true instead

terraform: AWS

• TO DO

Quick Start

Make sure terrform's in your $PATH:

terraform version

Write a provider file. The example below is for Digital Ocean.

• source = "digitalocean/digitalocean" tells terraform the cloud provider you're using
• variable "do_token" {} will prompt you for your personal access token
• variable "pvt_key" {} is the path to a private key file (remove this variable if using GPG + Yubikey for SSH)
• name = "example_key_name" is what you named the corresponding public key stored in your Digital Ocean account

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

variable "do_token" {}
#variable "pvt_key" {}

provider "digitalocean" {
  token = var.do_token
}

data "digitalocean_ssh_key" "terraform" {
  name = "example_key_name"
}

Write a terraform config file (.tf).

resource "digitalocean_droplet" "terraform-test" {
  count = 1
  image = "ubuntu-22-04-x64"
  name = "terraform-test-${count.index}"
  region = "sfo3"
  size = "s-1vcpu-1gb"
  ssh_keys = [
    data.digitalocean_ssh_key.terraform.id
  ]
  connection {
    host = self.ipv4_address
    user = "root"
    type = "ssh"
    # Use `private_key` if you're using a private key file
    #private_key = file(var.pvt_key)
    # Use `agent = true` if your ssh key is on a Yubikey and the agent can read it
    # Be patient while it's "Still creating...", it can take a minute or two before the Yubikey is called
    agent = true
    timeout = "2m"
  }
  provisioner "remote-exec" {
    inline = [
      "export PATH=$PATH:/usr/bin",
      "export DEBIAN_FRONTEND=noninteractive",
      # Update the package cache, enable UFW, install ansible, add a public GPG key, clone git repos
      "sudo apt-get update -yq",
      "sudo ufw allow ssh",
      "echo 'y' | sudo ufw enable",
      "apt install -yq python3-pip",
      "python3 -m pip install --user ansible",
      "gpg --keyid-format long --keyserver hkps://keyserver.ubuntu.com:443 --recv-keys '9906 9EB1 2D40 9EA9 3BD1  E52E B09D 00AE C481 71E0'",
      "cd ~/; git clone https://github.com/straysheep-dev/ansible-configs.git",
      "cd ~/; git clone https://github.com/straysheep-dev/linux-configs.git"
    ]
  }
}

Finally, the bash lines below do the following three things:

1. Initialize the directory (you only really do this once per directory)
2. Create a plan file (this shows you what you're about to deploy, do this every time)
3. Apply the plan file (deploy the infrastructure)

terraform init
terraform plan -out=infra.plan
terraform apply "infra.plan"

Once terraform is done, get the current state of the deployed resources (includes IP information):

terraform show

To stop and destroy / delete the resources:

terraform plan -destroy -out=destroy.plan
terraform apply "destroy.plan"

Deploy Specific Resources

If you have multiple .tf files in a project, but only want to deploy one or some of them, use the -target=<some.resource> option.

terraform plan -target=digitalocean_droplet.some-resource[0] [-target=digitalocean_droplet.some-resource[1] ...] -out=infra.plan
terraform apply infra.plan

Modifying Partial Resources in a Deployment

Force Recreation of Tainted Resources

If one or more resources in a deployment fails to deploy correctly, it will appear in the terraform show output as (tainted). You can replace the tainted resource(s) with -replace=<resource-name>, or destroy and re-apply them using the -target=<resource-name> option for each resource. In both cases this is done without tearing down the entire deployment.

The resource ID is the commented line above each resource block. This is also where the (tainted) indicator will appear. For example:

<SNIP>
# digitalocean_droplet.some-resource[0]: (tainted)
resource "digitalocean_droplet" "some-resource" {
<SNIP>

Use terraform show to show all resource ID's in the current deployment, and parse out which ones need fixed.

This bash snippet could be a starting point to iterate through all tainted resources and plan to replace them:

targets=""
keyword='tainted'
for resource in $(terraform show | grep -i "$keyword" | grep -P "^# \w+" | cut -d ' ' -f 2 | awk -F ':' '{print $1}'); do targets+="-replace=$resource "; done
terraform plan $targets -out=replace.plan
# terraform apply replace.plan

TIP: replace the keyword= variable with another string if, for example a set of resources you can match based on a keyword is not necessarily tainted, but need reprovisioned.

Your -replace commands to fix tainted resources would be:

terraform plan -replace=digitalocean_droplet.some-resource[0] [-replace=digitalocean_droplet.some-resource[1] ...] -out=infra.plan
terraform apply infra.plan

If you need to destroy resources instead of replace, this bash snippet could be a starting point to find all resources with "fedora" in the ID and plan to destroy them:

targets=""
keyword='fedora'
for resource in $(terraform show | grep -i "$keyword" | grep -P "^# \w+" | cut -d ' ' -f 2 | awk -F ':' '{print $1}'); do targets+="-target=$resource "; done
terraform plan -destroy $targets -out=destroy.plan
# terraform apply destroy.plan

The full -target commands to redeploy the resource(s) would be:

terraform plan -destroy -target=digitalocean_droplet.some-resource[0] [-target=digitalocean_droplet.some-resource[1] ...] -out=destroy.plan
terraform apply destroy.plan
terraform plan -target=digitalocean_droplet.some-resource[0] [-target=digitalocean_droplet.some-resource[1] ...] -out=infra.plan
terraform apply infra.plan

Terraform + Ansible

If you plan to deploy resources with terraform, and provision them with ansible, you can easily generate an inventory file from within the terraform project working directory.

group_name='[remotegroup]'
echo "$group_name" | tee inventory.ini; terraform show | grep -P '\bipv4_address\b' | awk -F'"' '{print $2":22 ansible_user=root"}' | tee -a inventory.ini

Reference the resulting file when using ansible -i <inventory-file>.

Secrets Management

Quick Start: Environment Variables

Configure Terraform Environment Variables

Environment variables are almost always needed in some way for DevOps, and they're also the best option for passing secrets to scripts if you do not have a vaulting solution.

The DigitalOcean documentation (and other sources) use this method to read input to write a secret into an environment variable without it appearing in the command line history.

echo "Enter API Key"; read -s api_key; export TF_VAR_do_token=$api_key

Using this method, the api_key environment variable only appears in the env of that shell session. Another shell running under the context of that user cannot see the api_key value.

Vaults

TO DO

• https://developer.hashicorp.com/vault/docs/what-is-vault
• https://bitwarden.com/help/secrets-manager-overview/

Vaults (or secrets managers) should be used to prevent secrets from appearing in scripts, configs, or environment variables.