Nix package manager install (single user) on Fedora Silverblue

Nix_package_manager_on_Fedora_Silverblue.md

Nix package manager on Fedora Silverblue

Warning

Disable composefs or enable root.transient before install and use nix on Fedora Silverblue 42.

Disable composefs

sudo rpm-ostree kargs --append='ostree.prepare-root.composefs=0' --reboot

Install nix

curl --proto '=https' --tlsv1.2 -sSf -L https://install.determinate.systems/nix | \
    sh -s -- install ostree --no-confirm --persistence=/var/lib/nix

Fix sudo

echo "Defaults  secure_path = /nix/var/nix/profiles/default/bin:/nix/var/nix/profiles/default/sbin:$(sudo printenv PATH)" | sudo tee /etc/sudoers.d/nix-sudo-env

Old way

• This is a single user install.

• For multi user install and without changing selinux mode: https://gist.github.com/matthewpi/08c3d652e7879e4c4c30bead7021ff73

• Please note that these instructions are not offically supported or condoned by Nix and are not guaranteed to always work, but from my testing everything seems to work perfectly fine.

• Change SELinux mode to permissive

  sudo setenforce Permissive
  sudo sed -i 's/SELINUX=enforcing/SELINUX=permissive/' /etc/selinux/config

• Create the nix directory in a persistent location

  sudo mkdir /var/lib/nix
  sudo chown $USER:$USER /var/lib/nix

• /etc/systemd/system/[email protected]

  [Unit]
  Description=Enable mount points in / for ostree
  ConditionPathExists=!%f
  DefaultDependencies=no
  Requires=local-fs-pre.target
  After=local-fs-pre.target
  
  [Service]
  Type=oneshot
  ExecStartPre=chattr -i /
  ExecStart=mkdir -p '%f'
  ExecStopPost=chattr +i /

• /etc/systemd/system/nix.mount

  [Unit]
  Description=Nix Package Manager
  DefaultDependencies=no
  After[email protected]
  Wants[email protected]
  Before=sockets.target
  After=ostree-remount.service
  BindsTo=var.mount
  
  [Mount]
  What=/var/lib/nix
  Where=/nix
  Options=bind
  Type=none
  
  [Install]
  WantedBy=local-fs.target

• Enable and mount the nix mount.

  # Ensure systemd picks up the newly created units
  sudo systemctl daemon-reload
  # Enable the nix mount on boot.
  sudo systemctl enable nix.mount
  # Mount the nix mount now.
  sudo systemctl start nix.mount

• Install Nix

  sh <(curl -L https://nixos.org/nix/install) --no-daemon

• Load Nix into your environment. Enable bash/fish/zhs completion for nix installed commands

  Load Nix into your environment. The installer modified ~/.bash_profile, but it isn't used when you start a terminal from desktop, it's only used when using a full shell login with bash -l, which doesn't happen on silverblue.

  tee --append $HOME/.bashrc <<EOF
  # Nix Package Manager
  if [ -e $HOME/.nix-profile/etc/profile.d/nix.sh ]; then
      source $HOME/.nix-profile/etc/profile.d/nix.sh;
  fi
  EOF

• Links:

  • https://tecadmin.net/how-to-disable-selinux-on-fedora/
  • https://gist.github.com/matthewpi/08c3d652e7879e4c4c30bead7021ff73
  • https://gist.github.com/queeup/26e36c6e3e701c0ba96c17dc5e5251be

currently getting errors when trying to install

 INFO Step: Enable (and start) the systemd unit `nix.mount`
ERROR Error saving receipt: RecordingReceipt("/nix", Os { code: 30, kind: ReadOnlyFilesystem, message: "Read-only file system" })
Error: 
   0: Install failure
   1: Error executing action
   2: Action `start_systemd_unit` errored
   3: Failed to execute command `"systemctl" "start" "nix.mount"`
      stdout: 
      stderr: A dependency job for nix.mount failed. See 'journalctl -xe' for details.

   3: exited with status code: 1
   3: 

and i see

nix-directory.service - Enable mount points in / for ostree
     Loaded: loaded (/etc/systemd/system/nix-directory.service; static)
    Drop-In: /usr/lib/systemd/system/service.d
             └─10-timeout-abort.conf, 50-keep-warm.conf
     Active: failed (Result: exit-code) since Mon 2025-04-21 18:24:43 CDT; 2min 45s ago
 Invocation: de9c4fc3f7a04a6bb48b69570af4797f
    Process: 8199 ExecStartPre=chattr -i / (code=exited, status=1/FAILURE)
    Process: 8200 ExecStopPost=chattr +i / (code=exited, status=1/FAILURE)
   Mem peak: 1.4M
        CPU: 6ms

any ideas?
composefs is disabled

i was able to fix it enabling composefs and doing this

I have no idea. Did you reboot after disabling composefs and before installing nix?

I have no idea. Did you reboot after disabling composefs and before installing nix?

Yes, on the other thread they report that in some instances disabling composefs is not enought, doing the other suggestion work tho