Merge pull request 'Worktree debian pxe' (#73) from worktree-debian-pxe into main

Reviewed-on: #73

docs/pxe-boot.md

@@ -15,6 +15,7 @@ rescue/inspection use.
 - TFTP root for first-stage bootloaders: `/srv/pxe/tftp`
 - iPXE entry script: `/srv/pxe/http/boot.ipxe`
 - Generated iPXE menu: `/srv/pxe/http/menu.ipxe`
+- Debian Minimal iPXE script: `/srv/pxe/http/debian.ipxe`
 - SystemRescue iPXE script: `/srv/pxe/http/systemrescue.ipxe`
 - TFTP fallback script: `/srv/pxe/tftp/autoexec.ipxe`
 - Boot binaries copied from the Nix `ipxe` package:
@@ -28,18 +29,23 @@ The host creates these directories with systemd tmpfiles:
 ```text
 /srv/pxe
 /srv/pxe/http
-/srv/pxe/http/images
+/srv/pxe/http/images  -> /mnt/pxe-images  (symlink to NFS share)
 /srv/pxe/http/auto-installer
 /srv/pxe/http/nixos-minimal
+/srv/pxe/http/debian
 /srv/pxe/http/systemrescue
 /srv/pxe/http/ubuntu
 /srv/pxe/http/rescue
 /srv/pxe/tftp
 ```
 
-Mount shared image storage under `/srv/pxe/http`, preferably
-`/srv/pxe/http/images` unless a menu entry expects files in a specific
-directory such as `/srv/pxe/http/auto-installer`.
+`/srv/pxe/http/images` is a symlink to `/mnt/pxe-images`, which is an NFSv4.2
+mount of `server.sweet.home:/tank/proxmox/pxe-images`
+(`modules/pxe-boot/mount-pxe-images.nix`). Place large images there (ISOs,
+disk images) rather than on the pxe-boot host's own root disk. For an LXC
+pxe-boot container the mount uses `nofail` (eager, non-blocking on server
+unavailability); for a Proxmox VM it uses `x-systemd.automount` (lazy,
+triggered on first access).
 
 The HTTP iPXE chain is:
 
@@ -54,6 +60,7 @@ The generated menu currently exposes entries for:
 
 - NixOS Auto-Installer
 - NixOS Minimal
+- Debian Minimal
 - SystemRescue environment
 - iPXE shell
 - Reboot
@@ -84,12 +91,38 @@ directory name (`auto-installer` / `nixos-minimal`), so each one's
 generated system name (`nixos-system-<name>-*`) is self-describing rather
 than the nixpkgs default of `nixos-system-nixos-*` for both.
 
+The Debian Minimal entry chains `http://<pxeServerIp>/debian.ipxe`, which loads
+the Debian bookworm netboot kernel and initrd from `/srv/pxe/http/debian/`. The
+`fetch-debian-netboot.service` oneshot downloads these files from
+`deb.debian.org` on first boot (idempotent — skips if files are already
+present):
+
+```text
+/srv/pxe/http/debian/linux      (Debian bookworm netboot kernel)
+/srv/pxe/http/debian/initrd.gz  (Debian bookworm netboot initrd)
+```
+
+The service requires outbound internet access on the pxe-boot host. To
+re-download (e.g. after a Debian point release), delete the files and restart
+the service:
+
+```bash
+rm /srv/pxe/http/debian/linux /srv/pxe/http/debian/initrd.gz
+systemctl restart fetch-debian-netboot.service
+```
+
+To update to a different Debian release, change `debianRelease` in
+`modules/build-types/pxe-boot.nix` and redeploy.
+
 The SystemRescue entry expects the source ISO at:
 
 ```text
 /srv/pxe/http/images/systemrescue.iso
 ```
 
+Since `/srv/pxe/http/images` is the NFS-backed symlink, place the ISO on the
+NFS share at `server.sweet.home:/tank/proxmox/pxe-images/systemrescue.iso`.
+
 The `stage-systemrescue.service` oneshot extracts that ISO into:
 
 ```text
@@ -113,6 +146,9 @@ After deployment by an operator, basic service checks are:
 ```bash
 curl http://pxe-boot/boot.ipxe
 curl http://pxe-boot/menu.ipxe
+curl http://pxe-boot/debian.ipxe
+curl -I http://pxe-boot/debian/linux
+curl -I http://pxe-boot/debian/initrd.gz
 curl http://pxe-boot/systemrescue.ipxe
 curl -I http://pxe-boot/systemrescue/sysresccd/boot/x86_64/vmlinuz
 curl -I http://pxe-boot/systemrescue/sysresccd/boot/x86_64/sysresccd.img

modules/build-types/pxe-boot.nix

@@ -21,6 +21,39 @@ let
     chain ${pxeBaseUrl}/boot.ipxe
   '';
 
+  debianRelease = "bookworm";
+  debianMirror = "https://deb.debian.org/debian";
+  debianNetbootBase = "${debianMirror}/dists/${debianRelease}/main/installer-amd64/current/images/netboot/debian-installer/amd64";
+
+  debianIpxe = pkgs.writeText "debian.ipxe" ''
+    #!ipxe
+
+    set base ${pxeBaseUrl}
+
+    kernel ''${base}/debian/linux
+    initrd ''${base}/debian/initrd.gz
+    boot
+  '';
+
+  fetchDebianNetboot = pkgs.writeShellScript "fetch-debian-netboot" ''
+    set -eu
+
+    dir="${httpRoot}/debian"
+    mirror="${debianNetbootBase}"
+
+    if [ -f "$dir/linux" ] && [ -f "$dir/initrd.gz" ]; then
+      echo "Debian ${debianRelease} netboot files already present; skipping download."
+      exit 0
+    fi
+
+    echo "Downloading Debian ${debianRelease} netboot kernel and initrd from $mirror ..."
+    ${pkgs.curl}/bin/curl -fsSL -o "$dir/linux.tmp" "$mirror/linux"
+    ${pkgs.curl}/bin/curl -fsSL -o "$dir/initrd.gz.tmp" "$mirror/initrd.gz"
+    mv "$dir/linux.tmp" "$dir/linux"
+    mv "$dir/initrd.gz.tmp" "$dir/initrd.gz"
+    echo "Debian ${debianRelease} netboot files staged."
+  '';
+
   systemRescueIpxe = pkgs.writeText "systemrescue.ipxe" ''
     #!ipxe
 
@@ -70,6 +103,7 @@ let
     menu PXE Boot Menu
     item auto-installer NixOS Auto-Installer
     item nixos-minimal NixOS Minimal
+    item debian Debian Minimal
     item rescue Rescue Environment
     item shell iPXE Shell
     item reboot Reboot
@@ -82,6 +116,9 @@ let
     :nixos-minimal
     chain ''${base}/nixos-minimal/netboot.ipxe
 
+    :debian
+    chain ''${base}/debian.ipxe
+
     :rescue
     chain ''${base}/systemrescue.ipxe
 
@@ -95,6 +132,7 @@ in
 {
   imports = [
     ../pxe-boot/stage-installer-artifacts.nix
+    ../pxe-boot/mount-pxe-images.nix
   ];
 
   environment.systemPackages = with pkgs; [
@@ -129,34 +167,56 @@ in
     openssh.settings.PermitRootLogin = "yes";
   };
 
-  systemd.tmpfiles.rules = [
-    "d ${pxeRoot} 0755 root root -"
-    "d ${httpRoot} 0755 root root -"
-    "d ${httpRoot}/images 0755 root root -"
-    "d ${httpRoot}/auto-installer 0755 root root -"
-    "d ${httpRoot}/nixos-minimal 0755 root root -"
-    "d ${httpRoot}/systemrescue 0755 root root -"
-    "d ${httpRoot}/ubuntu 0755 root root -"
-    "d ${httpRoot}/rescue 0755 root root -"
-    "d ${tftpRoot} 0755 root root -"
-    "C+ ${httpRoot}/boot.ipxe 0644 root root - ${bootIpxe}"
-    "C+ ${httpRoot}/menu.ipxe 0644 root root - ${menuIpxe}"
-    "C+ ${httpRoot}/systemrescue.ipxe 0644 root root - ${systemRescueIpxe}"
-    "C+ ${tftpRoot}/autoexec.ipxe 0644 root root - ${autoexecIpxe}"
-    "C+ ${tftpRoot}/ipxe.efi 0644 root root - ${pkgs.ipxe}/ipxe.efi"
-    "C+ ${tftpRoot}/undionly.kpxe 0644 root root - ${pkgs.ipxe}/undionly.kpxe"
-  ];
-
-  systemd.services.stage-systemrescue = {
-    description = "Stage SystemRescue ISO contents for HTTP PXE boot";
-    after = [
-      "local-fs.target"
-      "systemd-tmpfiles-setup.service"
+  systemd = {
+    tmpfiles.rules = [
+      "d ${pxeRoot} 0755 root root -"
+      "d ${httpRoot} 0755 root root -"
+      "L+ ${httpRoot}/images - - - - ${vars.nfsShares.proxmoxPxeImages.mountpoint}"
+      "d ${httpRoot}/auto-installer 0755 root root -"
+      "d ${httpRoot}/nixos-minimal 0755 root root -"
+      "d ${httpRoot}/systemrescue 0755 root root -"
+      "d ${httpRoot}/debian 0755 root root -"
+      "d ${httpRoot}/ubuntu 0755 root root -"
+      "d ${httpRoot}/rescue 0755 root root -"
+      "d ${tftpRoot} 0755 root root -"
+      "C+ ${httpRoot}/boot.ipxe 0644 root root - ${bootIpxe}"
+      "C+ ${httpRoot}/menu.ipxe 0644 root root - ${menuIpxe}"
+      "C+ ${httpRoot}/debian.ipxe 0644 root root - ${debianIpxe}"
+      "C+ ${httpRoot}/systemrescue.ipxe 0644 root root - ${systemRescueIpxe}"
+      "C+ ${tftpRoot}/autoexec.ipxe 0644 root root - ${autoexecIpxe}"
+      "C+ ${tftpRoot}/ipxe.efi 0644 root root - ${pkgs.ipxe}/ipxe.efi"
+      "C+ ${tftpRoot}/undionly.kpxe 0644 root root - ${pkgs.ipxe}/undionly.kpxe"
     ];
-    wantedBy = [ "multi-user.target" ];
-    serviceConfig = {
-      Type = "oneshot";
-      ExecStart = stageSystemRescue;
+
+    services = {
+      fetch-debian-netboot = {
+        description = "Download Debian ${debianRelease} netboot kernel and initrd for HTTP PXE boot";
+        after = [
+          "local-fs.target"
+          "systemd-tmpfiles-setup.service"
+          "network-online.target"
+        ];
+        wants = [ "network-online.target" ];
+        wantedBy = [ "multi-user.target" ];
+        serviceConfig = {
+          Type = "oneshot";
+          ExecStart = fetchDebianNetboot;
+          RemainAfterExit = true;
+        };
+      };
+
+      stage-systemrescue = {
+        description = "Stage SystemRescue ISO contents for HTTP PXE boot";
+        after = [
+          "local-fs.target"
+          "systemd-tmpfiles-setup.service"
+        ];
+        wantedBy = [ "multi-user.target" ];
+        serviceConfig = {
+          Type = "oneshot";
+          ExecStart = stageSystemRescue;
+        };
+      };
     };
   };
 

modules/pxe-boot/mount-pxe-images.nix

@@ -0,0 +1,24 @@
+{ config, vars, ... }:
+
+let
+  # Use the same FQDN approach as docker/mount-data.nix — a bare hostname is
+  # unreliable: systemd-resolved only tries LLMNR for single-label names, and
+  # a global search domain causes it to skip the interface-scoped LAN DNS.
+  nfsServer = "${vars.nfsServerHost}.${vars.homeDomain}";
+
+  # x-systemd.automount is unsupported inside LXC containers (systemd logs
+  # "Starting of <unit>.automount unsupported" and never mounts). Use nofail
+  # there so a boot with the NFS server unreachable doesn't hang instead.
+  automountOpts = if config.boot.isContainer then [ "nofail" ] else [ "x-systemd.automount" ];
+in
+{
+  fileSystems.${vars.nfsShares.proxmoxPxeImages.mountpoint} = {
+    device = "${nfsServer}:${vars.storageRoot}/${vars.nfsShares.proxmoxPxeImages.subpath}";
+    fsType = "nfs";
+    options = [
+      "nfsvers=4.2"
+      "_netdev"
+      "noatime"
+    ] ++ automountOpts;
+  };
+}