Enable console on serial port and print public ssh host key when booting

configuration/common/default.nix

@@ -51,5 +51,23 @@
     preliminarySelfsigned = true;
   };
 
+  # Print the ed25519 public ssh host key to console when booting
+  systemd.units."print-public-ssh-host-key.service" = {
+    enable = true;
+    text = ''
+      [Unit]
+      Description=print-public-ssh-host-key.service
+      Before=getty@tty1.service
+
+      [Service]
+      Type=oneshot
+      ExecStart=/run/current-system/sw/bin/bash -c "/run/current-system/sw/bin/echo ----- ED25519 PUBLIC SSH HOST KEY -----\
+                && /run/current-system/sw/bin/cut -d ' ' -f 1-2 /etc/ssh/ssh_host_ed25519_key.pub"
+      RemainAfterExit=no
+      StandardOutput=tty
+    '';
+    wantedBy = [ "multi-user.target" ];
+  };
+
   services.fstrim.enable = true;
 }

configuration/proxmox-vm/default.nix

@@ -1,4 +1,10 @@
 { ... }:
 {
+  # Enable console output on TTY1 and serial console
+  boot.kernelParams = [
+    "console=tty1"
+    "console=ttyS0,115200"
+  ];
+
   services.qemuGuest.enable = true;
 }