Add steps in install documentation

doc/install.md

@@ -0,0 +1,62 @@
+# Installing NixOS in a new node
+
+This article shows the steps to install NixOS in a node following the
+configuration of the repo.
+
+## Prepare the disk
+
+Create a main partition and label it `nixos` following [the manual][1].
+
+[1]: https://nixos.org/manual/nixos/stable/index.html#sec-installation-manual-partitioning.
+
+```
+# disk=/dev/sdX
+# parted $disk -- mklabel msdos
+# parted $disk -- mkpart primary 1MB 100%
+# parted $disk -- set 1 boot on
+```
+
+Then create an etx4 filesystem, labeled `nixos` where the system will be
+installed. **Ensure that no other partition has the same label.**
+
+```
+# mkfs.ext4 -L nixos "${disk}1"
+# mount ${disk}1 /mnt
+# lsblk -f $disk
+NAME   FSTYPE LABEL UUID                                 MOUNTPOINT
+sdX
+`-sdX1 ext4   nixos 10d73b75-809c-4fa3-b99d-4fab2f0d0d8e /mnt
+```
+
+## Prepare nix and nixos-install
+
+Mount the nix store from the xeon07 node in read-only /nix.
+
+```
+# mkdir /nix
+# mount -o ro xeon07:/nix /nix
+```
+
+Get the nix binary and nixos-install tool from xeon07:
+
+```
+# ssh xeon07 'readlink -f $(which nix)'
+/nix/store/0sxbaj71c4c4n43qhdxm31f56gjalksw-nix-2.13.3/bin/nix
+# ssh xeon07 'readlink -f $(which nixos-install)'
+/nix/store/9yq8ps06ysr2pfiwiij39ny56yk3pdcs-nixos-install/bin/nixos-install
+```
+
+And add them to the PATH:
+
+```
+# export PATH=$PATH:/nix/store/0sxbaj71c4c4n43qhdxm31f56gjalksw-nix-2.13.3/bin
+# export PATH=$PATH:/nix/store/9yq8ps06ysr2pfiwiij39ny56yk3pdcs-nixos-install/bin/
+# nix --version
+nix (Nix) 2.13.3
+```
+
+## Build the nixos kexec image
+
+```
+# nix build .#nixosConfigurations.xeon02.config.system.build.kexecTree -v
+```

xeon02/configuration.nix

@@ -1,12 +1,15 @@
 { config, pkgs, modulesPath, lib, ... }:
 
 {
-  imports = [ ../common/main.nix (modulesPath + "/installer/netboot/netboot-minimal.nix") ];
+  imports = [
+    #(modulesPath + "/installer/netboot/netboot-minimal.nix")
+    ../common/main.nix
+  ];
 
   # Select the this using the ID to avoid mismatches
   boot.loader.grub.device = "/dev/disk/by-id/wwn-0x55cd2e414d535629";
   #programs.ssh.forwardX11 = false;
-  programs.ssh.setXAuthLocation = lib.mkForce true;
+  #programs.ssh.setXAuthLocation = lib.mkForce true;
 
   networking = {
     hostName = "xeon02";