01/02: doc: Fix PXE boot procedure documented in infra-handbook.org.

[Maxim Cournoyer]

apteryx pushed a commit to branch master
in repository maintenance.

commit ed575f27e7bdd5fdf4fbb11d2db5e28ff76930c4
Author: Maxim Cournoyer <maxim.cournoyer@gmail.com>
AuthorDate: Mon Apr 24 14:47:57 2023 -0400

    doc: Fix PXE boot procedure documented in infra-handbook.org.
    
    * doc/infra-handbook.org (Repairing a non-bootable Guix System via a
    PXE booted image): Describe procedure as done via the BIOS instead of
    the iDRAC web page.
---
 doc/infra-handbook.org | 43 ++++++++++++++++++++++++++++++++++---------
 1 file changed, 34 insertions(+), 9 deletions(-)

diff --git a/doc/infra-handbook.org b/doc/infra-handbook.org
index f018ab6..a5e0a8f 100644
--- a/doc/infra-handbook.org
+++ b/doc/infra-handbook.org
@@ -144,11 +144,19 @@ mode fallback to a network (PXE) boot, and using the 
serial console to
 navigate the boot menus.
 
 Pressing F12 as suggested during the boot to reach PXE doesn't seem to
-work.  An alternative way is to visit the "BIOS Settings" tab of the
-"Configuration" via the iDAC web interface, navigate to the "One-Time
-Boot Device List" section, choose the PXE device entry for the "UEFI
-Boot Sequence Device" drop-down menu, press the "Apply" button, then
-"Apply And Reboot" at the bottom.
+work.  The most reliable way I've found is to change the ~Boot
+Settings~ in a persistent fashion by entering the System Setup (F2) at
+boot:
+
+System Setup
+ - System BIOS
+   - Boot Settings
+     - UEFI Boot Settings
+
+Leave only the PXE Device checkbox enabled, then press ESC, ESC, ESC,
+Yes, OK, ESC and YES to save and exit.  The PXE boot typically
+succeeds on the second reboot, which it attempts automatically after
+failing once.
 
 The images are made available by the MDC infrastructure team via
 [[https://github.com/cobbler/cobbler][Cobbler]] , and only a few of the images 
available are bootable (sadly,
@@ -164,10 +172,27 @@ connect to from the ~hydra-guix-129~ or ~berlin~ machines.
 You can then mount the file systems and modify ~/boot/grub/grub.cfg~
 or anything.  If you need to reconfigure the machine, you can refer
 to: info:guix#Chrooting to chroot into an existing system, except
-you'll need to pass the ~--no-substitutes~ argument to ~guix-daemon~,
-otherwise it'll loop trying to fetch substitutes from
-https://ci.guix.gnu.org, in vain.  If the reconfiguration hangs, you
-may need to use ~--no-grafts~.
+you'll need to use the
+~--substitute-urls=https://bordeaux.guix.gnu.org~ to avoid blocking on
+attempting to fetch substitutes from https://ci.guix.gnu.org, in vain.
+If the reconfiguration hangs, you may also need to use ~--no-grafts~.
+
+To allow connecting to a root shell from a remote machine
+(e.g. ~berlin~), set the ~PermitRootLogin~ to ~yes~ in
+=/etc/ssh/sshd_config= and set a password for the ~root~ user via the
+~passwd~ command, then ~systemctl restart sshd~.
+
+** Scribbled Notes
+To replicate ~node-129~'s file system under ~/mnt~, use:
+
+#+begin_example
+mount -o subvol=@root /dev/mapper/mpathb /mnt
+mount -o subvol=@cache /dev/mapper/mpathb /mnt/var/cache
+mount -o subvol=@home /dev/mapper/mpathb /mnt/home
+mount /dev/sda3 /mnt/boot/
+mount /dev/sda2 /mnt/boot/efi
+mount /dev/sdb2 /mnt/boot/efi2/
+#+end_example
 
 * Btrfs file system