infra/main.tf

@@ -14,6 +14,9 @@ locals {
   bootstrap_script = templatefile("${path.module}/scripts/bootstrap.sh.tftpl", {
     deploy_user = var.deploy_user
   })
+
+  # IDs for every named key in var.ssh_key_names - installed on every server.
+  ssh_key_ids = [for k in data.hcloud_ssh_key.main : k.id]
 }
 
 module "network" {
@@ -30,7 +33,7 @@ module "dev" {
   server_type            = var.dev_server_type
   image                  = var.server_image
   location               = var.location
-  ssh_key_id             = data.hcloud_ssh_key.main.id
+  ssh_key_ids            = local.ssh_key_ids
   network_id             = module.network.id
   private_ip             = var.dev_private_ip
   volume_size            = var.dev_volume_size
@@ -51,7 +54,7 @@ module "prod" {
   server_type            = var.prod_server_type
   image                  = var.server_image
   location               = var.location
-  ssh_key_id             = data.hcloud_ssh_key.main.id
+  ssh_key_ids            = local.ssh_key_ids
   network_id             = module.network.id
   private_ip             = var.prod_private_ip
   volume_size            = var.prod_volume_size
@@ -69,7 +72,7 @@ module "vpn" {
   server_type            = var.vpn_server_type
   image                  = var.server_image
   location               = var.location
-  ssh_key_id             = data.hcloud_ssh_key.main.id
+  ssh_key_ids            = local.ssh_key_ids
   allowed_ssh_source_ips = var.allowed_ssh_source_ips
   bootstrap_script       = local.bootstrap_script
   ssh_private_key_path   = var.ssh_private_key_path

infra/modules/dev/main.tf

@@ -54,7 +54,7 @@ resource "hcloud_server" "this" {
   server_type  = var.server_type
   image        = var.image
   location     = var.location
-  ssh_keys     = [var.ssh_key_id]
+  ssh_keys     = var.ssh_key_ids
   firewall_ids = [hcloud_firewall.this.id]
 
   network {

infra/modules/dev/variables.tf

@@ -13,9 +13,9 @@ variable "location" {
   type        = string
 }
 
-variable "ssh_key_id" {
+variable "ssh_key_ids" {
-  description = "ID of the Hetzner Cloud SSH key to install on the server."
+  description = "IDs of the Hetzner Cloud SSH keys to install on the server."
-  type        = string
+  type        = list(string)
 }
 
 variable "network_id" {
@@ -49,7 +49,7 @@ variable "bootstrap_script" {
 }
 
 variable "ssh_private_key_path" {
-  description = "Local path to the private key matching var.ssh_key_id, used to run the bootstrap script over SSH."
+  description = "Local path to the private key matching one of var.ssh_key_ids, used to run the bootstrap script over SSH."
   type        = string
 }
 

infra/modules/prod/main.tf

@@ -81,7 +81,7 @@ resource "hcloud_server" "this" {
   server_type  = var.server_type
   image        = var.image
   location     = var.location
-  ssh_keys     = [var.ssh_key_id]
+  ssh_keys     = var.ssh_key_ids
   firewall_ids = [hcloud_firewall.this.id]
 
   network {

infra/modules/prod/variables.tf

@@ -13,9 +13,9 @@ variable "location" {
   type        = string
 }
 
-variable "ssh_key_id" {
+variable "ssh_key_ids" {
-  description = "ID of the Hetzner Cloud SSH key to install on the server."
+  description = "IDs of the Hetzner Cloud SSH keys to install on the server."
-  type        = string
+  type        = list(string)
 }
 
 variable "network_id" {
@@ -49,6 +49,6 @@ variable "bootstrap_script" {
 }
 
 variable "ssh_private_key_path" {
-  description = "Local path to the private key matching var.ssh_key_id, used to run the bootstrap script over SSH."
+  description = "Local path to the private key matching one of var.ssh_key_ids, used to run the bootstrap script over SSH."
   type        = string
 }

infra/modules/vpn/main.tf

@@ -36,7 +36,7 @@ resource "hcloud_server" "this" {
   server_type  = var.server_type
   image        = var.image
   location     = var.location
-  ssh_keys     = [var.ssh_key_id]
+  ssh_keys     = var.ssh_key_ids
   firewall_ids = [hcloud_firewall.this.id]
 
   connection {

infra/modules/vpn/variables.tf

@@ -13,9 +13,9 @@ variable "location" {
   type        = string
 }
 
-variable "ssh_key_id" {
+variable "ssh_key_ids" {
-  description = "ID of the Hetzner Cloud SSH key to install on the server."
+  description = "IDs of the Hetzner Cloud SSH keys to install on the server."
-  type        = string
+  type        = list(string)
 }
 
 variable "allowed_ssh_source_ips" {
@@ -29,6 +29,6 @@ variable "bootstrap_script" {
 }
 
 variable "ssh_private_key_path" {
-  description = "Local path to the private key matching var.ssh_key_id, used to run the bootstrap script over SSH."
+  description = "Local path to the private key matching one of var.ssh_key_ids, used to run the bootstrap script over SSH."
   type        = string
 }

infra/ssh.tf

@@ -1,3 +1,4 @@
 data "hcloud_ssh_key" "main" {
-  name = var.ssh_key_name
+  for_each = toset(var.ssh_key_names)
+  name     = each.value
 }

infra/terraform.tfvars.example

@@ -4,12 +4,13 @@
 # The Hetzner API token is NOT set here: export it as HCLOUD_TOKEN in your shell
 # before running tofu plan/apply.
 
-# Name of an SSH key already uploaded to your Hetzner Cloud project
+# Names of SSH keys already uploaded to your Hetzner Cloud project
-# (Console > Security > SSH Keys). Required.
+# (Console > Security > SSH Keys). All of them are installed on every server. Required.
-ssh_key_name = "your-key-name"
+ssh_key_names = ["your-key-name", "laptop", "phone"]
 
-# Local path to the private key matching ssh_key_name above. OpenTofu uses this
+# Local path to the private key matching ONE of ssh_key_names above (doesn't need
-# once per server to upload and run the post-install bootstrap script
+# to be all of them - just one you hold). OpenTofu uses this once per server to
+# upload and run the post-install bootstrap script
 # (infra/scripts/bootstrap.sh.tftpl) immediately after creation. Required.
 ssh_private_key_path = "~/.ssh/id_ed25519"
 

infra/variables.tf

@@ -70,9 +70,9 @@ variable "prod_private_ip" {
   default     = "10.0.1.11"
 }
 
-variable "ssh_key_name" {
+variable "ssh_key_names" {
-  description = "Name of an SSH key already uploaded to your Hetzner Cloud project (Console > Security > SSH Keys)."
+  description = "Names of SSH keys already uploaded to your Hetzner Cloud project (Console > Security > SSH Keys). All are installed on every server."
-  type        = string
+  type        = list(string)
 }
 
 variable "allowed_ssh_source_ips" {
@@ -82,7 +82,7 @@ variable "allowed_ssh_source_ips" {
 }
 
 variable "ssh_private_key_path" {
-  description = "Local path to the private key matching var.ssh_key_name. Used once per server by OpenTofu to upload and run the post-install bootstrap script over SSH immediately after creation (see infra/scripts/bootstrap.sh.tftpl)."
+  description = "Local path to the private key matching one of var.ssh_key_names - only needs to be a key you hold yourself, not all of them. Used once per server by OpenTofu to upload and run the post-install bootstrap script over SSH immediately after creation (see infra/scripts/bootstrap.sh.tftpl)."
   type        = string
 }
 

readme.md

@@ -68,9 +68,9 @@ architecture-beta
 .
 ├── infra/                    # OpenTofu (Terraform-compatible) config — provisions the 3 servers, network, firewalls, volumes
 │   ├── main.tf                # root module: wires network + dev/prod/vpn modules together
-│   ├── variables.tf           # shared inputs (sizes, locations, IP ranges, SSH key name)
+│   ├── variables.tf           # shared inputs (sizes, locations, IP ranges, SSH key names)
 │   ├── outputs.tf             # pass-through outputs from each host module
-│   ├── ssh.tf                 # looks up the SSH key already uploaded to Hetzner Cloud
+│   ├── ssh.tf                 # looks up each SSH key already uploaded to Hetzner Cloud
 │   ├── versions.tf            # provider requirements
 │   ├── terraform.tfvars.example
 │   ├── scripts/
@@ -98,7 +98,7 @@ Each of `services/dev`, `services/prod`, `services/vpn` follows the same convent
 ## Prerequisites
 
 - A [Hetzner Cloud](https://console.hetzner.cloud/) project and API token
-- An SSH key uploaded to that project (Console → Security → SSH Keys), and the matching private key available locally (OpenTofu uses it once per server to run the post-install bootstrap — see below)
+- One or more SSH keys uploaded to that project (Console → Security → SSH Keys) - all are installed on every server - plus the private key matching one of them available locally (OpenTofu uses it once per server to run the post-install bootstrap — see below)
 - [OpenTofu](https://opentofu.org/docs/intro/install/) `>= 1.6.0`
 - DNS records for the domains in [Service inventory](#service-inventory) pointed at the relevant server's public IP
 
@@ -110,7 +110,7 @@ Docker + the Compose plugin no longer need installing by hand — the bootstrap
 cd infra
 export HCLOUD_TOKEN=your-hetzner-api-token   # never commit this
 cp terraform.tfvars.example terraform.tfvars
-$EDITOR terraform.tfvars                     # set ssh_key_name and ssh_private_key_path at minimum
+$EDITOR terraform.tfvars                     # set ssh_key_names and ssh_private_key_path at minimum
 
 tofu init
 tofu plan
@@ -131,7 +131,7 @@ Useful outputs: `tofu output dev_ipv4`, `tofu output prod_ipv4`, `tofu output vp
 Immediately after each `hcloud_server` is created, OpenTofu uploads and runs [`infra/scripts/bootstrap.sh.tftpl`](infra/scripts/bootstrap.sh.tftpl) over SSH as `root` (`connection` + `file`/`remote-exec` provisioners in each `modules/<host>/main.tf`). It:
 
 - installs Docker Engine + the Compose plugin
-- creates a non-root sudo user (`var.deploy_user`, default `deploy`) with the same SSH key as root, in the `sudo` and `docker` groups
+- creates a non-root sudo user (`var.deploy_user`, default `deploy`) with the same SSH keys as root, in the `sudo` and `docker` groups
 - hardens `sshd`: password authentication off, root login restricted to key-only (`PermitRootLogin prohibit-password`)
 - installs and enables `unattended-upgrades` for automatic security patches