dotfiles

Install system settings:

nixos-rebuild switch --use-remote-sudo --flake .#<hostname>

For pascal:

nixos-rebuild switch --use-remote-sudo --flake .#pascal --target-host pascal

Update:

nix flake update
nixos-rebuild switch --use-remote-sudo --flake .#<hostname>

Swift desktop install with disko and nixos-anywhere

First off, check that the configuration you want to apply has some way to access your machine once the installation is done (e.g. ssh daemon turned on and key configured, or initial password).

In theory, nixos-anywhere is pretty much a one-click install. In practice, the swift notebook still refuses to boot any NixOS stick in UEFI mode which makes things more difficult.

Workaround for booting into nixos installer

On target machine swift:

• Change BIOS setting to allow Legacy and UEFI boot mode
• Boot Ubuntu Live stick
• Change to tty3 with CTRL+ALT+F3 to avoid Ubuntu GUI

# Install and enable openssh daemon
sudo apt install openssh-server
sudo systemctl start ssh
# Note ip address of this machine
ip addr
# Set password for user "ubuntu"
passwd

On source machine:

nix run github:nix-community/nixos-anywhere -- --flake '.#swift' ubuntu@<ip>

This will run kexec and then the target machine will boot into nixos.

The actual install

On the installer at the target machine, login as user nixos and then:

# Create the password file for disk encryption
# -n is important so that echo does not create a newline
echo -n "password" > /tmp/secret.key
# Note down new ip address
ip addr
# Change root password
sudo su
passwd

On source machine:

nix run github:nix-community/nixos-anywhere -- --flake '.#swift' root@<other-ip>

This won't run kexec again because we're already in a nixos installer on the target. It should then run disk formatting, install nixos and then reboot the machine.

On swift, change BIOS settings back to UEFI only after the install.

Manual steps after new desktop install

• Set up custom keyboard shortcuts
  • Some shortcuts are handled by dconf and are applied via home-manager
  • Shortcuts in the "custom" section need to be filled manually:
    • Terminator
    • Firefox
    • Thunderbird
• Set desktop background
• Set up KeePassXC (including browser extension settings)
• Install browser bookmarks
  • Chrome: automatic restore from file in .config/chromium/Default/Bookmarks or restore from bookmarks.html
  • Firefox: restore from bookmarks.json
• Install browser extensions
  • Privacy Badger
  • vim something
  • KeepassXC
• Link signal-desktop
• Enable tailscale (sudo tailscale up)
• Set up nextcloud sync client
• Set up joplin WebDAV sync

Manual steps for a new Raspberry install

Building an SD card image for Raspberry:

nix build --flake .#nixosConfigurations.rust.config.system.build.sdImage

Flash the image to SD card or USB disk, then boot. SSH access should work out of the box.

• Tailscale: sudo tailscale up
• Home assistant: Install backup to ~/home-assistant by extracting the backup.tar file into the directory
• Nextcloud:
  • Restore postgres database backup (see below)
  • Restore nextcloud folder
  • Restore nginx certs and password files
  • Maybe: reinstall "External Storage" App via GUI and enable link to local scanner folder
• Adguard home:
  • Set up login (instructions in adguard.nix)
• Grafana:
  • For a new install admin password is admin.
• ha-relay: Set up access token (copy file)
• nomnombring-backend: Create config file and recipes file

Raspi boot issues - 2023-11-01

So the Raspi 4 suddenly stopped booting. Several hours of debugging later and it turns out that when two USB drives (the one with the OS and the backup drive) are connected, the boot sometimes fails. When attaching a screen you can see that the Raspi attempts to boot from network with various filenames.

Seems to be a U-Boot issue. The order in which the disks are discovered during startup is not fixed and U-Boot only tries to boot the first usb storage disk it finds. So when it finds the backup drive first, it won't manage to boot.

WIP Fix:

Attach screen and keyboard to Raspi, cancel boot process by hitting any key to get to U-Boot command line.

U-Boot> printenv boot_targets
boot_targets=mmc0 mmc1 mmc2 usb0 pxe dhcp
U-Boot> printenv bootcmd_usb0
bootcmd_usb0=devnum=0; run usb_boot
U-Boot> printenv bootcmd_usb1
## Error: "bootcmd_usb1" not defined
U-Boot> usb storage
  Device 0: Vendor: .....
  Device 1: Vendor: .....

-> Only usb0 is available as a boot target even though two disks are attached. You can also reboot multiple times and see if the order changes. usb list is another useful command and it can be executed with usb list 0 as well.

U-Boot> setenv boot_targets 'mmc0 mmc1 mmc2 usb0 usb1 pxe dhcp'
U-Boot> setenv bootcmd_usb1 'devnum=1; run usb_boot'
U-Boot> saveenv ## This last step doesn't work yet, so we can't persist the config
Saving environment to FAT... Card did not respond to voltage select! : -110
** Bad device specification mmc 0 **
Failed (1)

Backups

Swift

Can be started via the systemd user service.

sudo systemctl start backup.mount
systemctl --user start backup-swift.service

Dconf settings (manual)

Gnome settings are not backed up automatically. The file home-manager/dconf-settings.nix manages the most important settings via nix. It can be updated as follows:

# 1. Backup the existing settings
dconf dump / > dconf-settings.ini
# 2. Edit and manually remove everything that should not be transferred (e.g. window positions etc.)
vim dconf-settings.nix
# 3. Convert to nix
nix-shell -p dconf2nix --command "dconf2nix -i dconf-settings.ini -o dconf-settings.nix"
# 4. Compare and overwrite home-manager/dconf-settings.nix

Raspberry Pis

Backups for Home Assistant and Nextcloud are run nightly.

Nextcloud Database (manual backup)

The nextcloud database dump is needed when restoring an entire install (not just the files) from backup.

See also the official docs.

# Create backup
sudo -u postgres pg_dump nextcloud -f /tmp/nextcloud-db_`date +"%Y%m%d"`.bak
# Restore from backup
sudo -u postgres psql -d template1 -c "DROP DATABASE \"nextcloud\";"
sudo -u postgres psql -d template1 -c "CREATE DATABASE \"nextcloud\";"
sudo -u postgres psql -d nextcloud -f nextcloud-db_000000.bak

Garbage collection

sudo nix-collect-garbage --older-than 30d