Use Official tunnel mod and disable shell of user and minor fixes

main.tf

@@ -1,21 +1,5 @@
 locals {
   resource_name = var.name_prefix == "" ? var.name : "${var.name_prefix}-${var.name}"
-
-  # Default SSH config
-  sshd_config = <<-EOT
-Port ${var.ssh_port}
-AllowTcpForwarding yes
-AuthorizedKeysFile      .ssh/authorized_keys
-ClientAliveCountMax 100
-ClientAliveInterval 30
-GatewayPorts clientspecified
-PasswordAuthentication no
-PermitTunnel yes
-PidFile /config/sshd.pid
-TCPKeepAlive no
-X11Forwarding no
-HostKey /config/ssh_host_keys/ssh_host_rsa_key
-    EOT
 }
 
 resource "kubernetes_config_map" "main" {
@@ -27,7 +11,12 @@ resource "kubernetes_config_map" "main" {
   data = {
     "authorized_keys" = var.ssh_keys
     "motd"            = "Welcome to ${var.motd_name}.\n"
-    "sshd_config"     = var.sshd_config == "" ? local.sshd_config : var.sshd_config
+    "delete-generated-ssh-keys"            = <<EOT
+#!/bin/bash
+echo "**** remove not needed ecdsa and ed25519 keys ****"
+rm /config/ssh_host_keys/ssh_host_ecdsa*
+rm /config/ssh_host_keys/ssh_host_ed25519*
+EOT
   }
 }
 
@@ -95,14 +84,14 @@ resource "kubernetes_deployment" "main" {
         }
 
         volume {
-          name = "sshd-config"
+          name = "delete-generated-ssh-keys"
 
           config_map {
             name = local.resource_name
 
             items {
-              key  = "sshd_config"
-              path = "sshd_config"
+              key  = "delete-generated-ssh-keys"
+              path = "delete-generated-ssh-keys"
             }
           }
         }
@@ -133,82 +122,72 @@ resource "kubernetes_deployment" "main" {
           }
         }
 
-        volume {
-          name = "config"
-          empty_dir {}
-        }
+        container {
+          name  = local.resource_name
+          image = "${var.image_repository}:${var.image_tag}"
 
-        init_container {
-          name  = "${local.resource_name}-init"
-          image = "busybox:1.36.1-uclibc"
+          env {
+            # Ref: https://github.com/linuxserver/docker-mods/tree/openssh-server-ssh-tunnel
+            name  = "DOCKER_MODS"
+            value = "linuxserver/mods:openssh-server-ssh-tunnel"
+          }
 
-          command = ["sh", "-c", "cp -r /defaults/. /config && chmod 600 /config/ssh_host_keys/ssh_host_rsa_key"]
+          env {
+            name  = "PUBLIC_KEY_FILE"
+            value = "/defaults/authorized_keys"
+          }
+
+          env {
+            name  = "SHELL_NOLOGIN"
+            value = var.shell_no_login
+          }
+
+          env {
+            name  = "USER_NAME"
+            value = var.ssh_user
+          }
 
           volume_mount {
             name       = "authorized-keys"
-            mount_path = "/defaults/.ssh/authorized_keys"
+            mount_path = "/defaults/authorized_keys"
             sub_path   = "authorized_keys"
           }
 
           volume_mount {
-            name       = "sshd-config"
-            mount_path = "/defaults/ssh_host_keys/sshd_config"
-            sub_path   = "sshd_config"
+            name       = "delete-generated-ssh-keys"
+            mount_path = "/custom-cont-init.d/delete-generated-ssh-keys"
+            sub_path   = "delete-generated-ssh-keys"
+            read_only = true
           }
 
           volume_mount {
             name       = "ssh-host-rsa-key"
-            mount_path = "/defaults/ssh_host_keys/ssh_host_rsa_key"
+            mount_path = "/config/ssh_host_keys/ssh_host_rsa_key"
             sub_path   = "ssh_host_rsa_key"
           }
 
           volume_mount {
             name       = "ssh-host-rsa-key-public"
-            mount_path = "/defaults/ssh_host_keys/ssh_host_rsa_key_public"
+            mount_path = "/config/ssh_host_keys/ssh_host_rsa_key_public"
             sub_path   = "ssh_host_rsa_key_public"
           }
 
-          volume_mount {
-            name       = "config"
-            mount_path = "/config"
-          }
-        }
-
-        container {
-          name  = local.resource_name
-          image = "${var.image_repository}:${var.image_tag}"
-
-          env {
-            name  = "USER_NAME"
-            value = var.ssh_user
-          }
-
-
           volume_mount {
             name       = "motd"
             mount_path = "/etc/motd"
             sub_path   = "motd"
           }
 
-          volume_mount {
-            name       = "config"
-            mount_path = "/config"
-          }
-
           liveness_probe {
             tcp_socket {
               port = var.ssh_port
             }
-
-            initial_delay_seconds = 30
           }
 
           readiness_probe {
             tcp_socket {
               port = var.ssh_port
             }
-
-            initial_delay_seconds = 30
           }
         }
       }
@@ -247,7 +226,7 @@ resource "kubernetes_service" "main" {
       target_port = var.ssh_port
     }
 
-    type = var.svc_type
+    type                = var.svc_type
     load_balancer_class = var.load_balancer_class
   }
 

variables.tf

@@ -27,12 +27,6 @@ variable "ssh_keys" {
   description = "List of SSH keys to be added to the authorized keys list. Should be in the same format as the 'authorized_keys' file, represented in Heredoc style as a multi-line string value."
 }
 
-variable "sshd_config" {
-  type        = string
-  default     = ""
-  description = "Configuration file for SSH. If not defined it will use the default."
-}
-
 variable "ssh_host_rsa_key" {
   type        = string
   default     = ""
@@ -90,5 +84,12 @@ variable "svc_port" {
 variable "load_balancer_class" {
   type        = string
   default     = null
-  description = "The class of the load balancer implementation this Service belongs to. If specified, the value of this field must be a label-style identifier, with an optional prefix. This field can only be set when the svc_type is LoadBalancer" 
+  description = "The class of the load balancer implementation this Service belongs to. If specified, the value of this field must be a label-style identifier, with an optional prefix. This field can only be set when the svc_type is LoadBalancer"
 }
+
+variable "shell_no_login" {
+  type        = bool
+  default     = true
+  description = "Determines whether it is possible to login into shell when connecting via SSH with the created user. By default the user is not allowed to shell via SSH, to change this behaviour please set this variable to 'false'"
+}
+