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A NixOS flake. It is a work-in-progress rewrite of my old configurations.

Design

Wrappers as configurations

Instead of symlinking configuration files to their appropriate directories, e.g. ~, we instead

• package configuration files with Nix,
• place them on the /nix/store, and
• wrap our binaries to point them to their appropriate configuration files.

Almost all programs should support this. A notable exception is GTK, for which we still use symlinks.

For programs with sufficiently complex configurations, and/or a need to be portable, we separate their configurations into their own flakes. These are done for

• Neovim,
• tmux, and
• the Suckless suite.

A notable advantage of this is that it leaves the home directory with almost purely just state. The use of this will be further explored below.

Impermanence

This is the wiping of root at every reboot, which can be done by either

• placing root on tmpfs, or
• maintaining an 'empty' snapshot (with filesystems such as ZFS or BtrFS), and rolling back to it.

This results in our machines being stateless by default. To maintain state, we would

• maintain a persistence directory, e.g. /nix/persist),
• place it on an actual volume, and
• bind-mount paths for which we want to maintain state to it.

Reverse-impermanence

Unfortunately, bind mounts incurs a non-trivial performance overhead. This renders read and write speeds much slower.

Since this flake handles mostly desktop configurations, I would imagine this to be more an issue in the home directories, where the user would spend most of their time.

Fortunately, as mentioned above the use of wrappers as configuration renders the home directory to be comprised of almost entirely just state. As a result, we can simply place the entirety of ~ on its own drive, instead of a volatile tmpfs.

To eliminate unwanted state, we could instead mount tmpfs there. Some examples of paths we would want to do this for includes

• ~/.cache,
• ~/.local, and
• ~/.icons.

We would therefore be able to minimise the performance overhead experienced in actual day-to-day use.