We learned from the previous experience that, setting up a full system out of only Nix package manager, is a tough task. However, NixOs exists for that exact purpose: leverage the Nix package manager to the max and allow you to have a reproducible system. Plus, you can find a lot of documentation and examples out there where you can get inspired from.

In particular, I came across Gabriel Volpe's NixOs configuration and I was quite impressed by what he had done. It seems very easy to setup, very complete and it uses XMonad, a tiling window manager written in Haskell. Plus, he has an article on that!! So, it should be easy to extend and that's exactly what I want. Let's write down the steps to take

• Setup a NixOs Virtual Machine
• Take my previous Nix configuration
• Fork Gabriel's Configuration
• Merge them together
• Try the result on a NixOs virtual machine

In addition, NixOs comes also as minimal ISO, so you can configure it from the ground up instead of having to remove the software you might not want.

Ah, I forgot to say that Gabriel is still developing his configuration! Then, if he will add something I might end up stealing it just by doing a quick merge from his repository. 😎

let's install minimal NixOs on a VirtualBox. You can find the ISO here. I just noticed how you can directly download a VirtualBox Virtual Machine straight out from the site! Unfortunately it is the Plasma version, meanwhile we want to start from the minimal one.

At this stage, I'm just going to install the plain system and then work on the configuration on the host machine. When, I will feel confident and satisfied enough about the configuration, I will clone it into the Virtual Machine and test it out.

I do so because it's extremely easier to work into the host machine instead of doing the changes inside the virtual machine. Basically, I'll use that as a compiler until everything is fine.

It boots into a shell as expected, but what I liked is the suggestion to type nixos-help and get back the whole detailed manual about the system. A comprehensive guide with all the links to different sections

You have to be patient and read the manual about the different options you have for installation, but at the end it's not that difficult to do, you need to:

• Partition your drive
• Format the drive
• Generate and write your configuration file
• install the system

# for Legacy boot, see manual for uefi
sudo parted /dev/sda -- mklabel msdos
 # Create primary partition, but 8gb for the swap
sudo parted /dev/sda -- mkpart primary 1MiB -8GiB
# Create the Swap partition
sudo parted /dev/sda -- mkpart primary linux-swap -8GiB 100%
# Format primary partition
sudo mkfs.ext4 -L nixos /dev/sda1
# Format Swap
sudo mkswap -L swap /dev/sda2
# Mount the primary partition into mnt
sudo mount /dev/disk/by-label/nixos /mnt
# Enable the swap
sudo swapon /dev/sda2
# Generate the configuration
sudo nixos-generate-config --root /mnt
# Edit configurations
sudo nano /mnt/etc/nixos/configuration.nix
# Install the system
sudo nixos-install

I can see how it could be tedious, but if you want there's already someone else online who has crafted scripts to make this pretty much automatic, eg this installation script. If you want to see a video regarding installing NixOs, you can find it in here.

Edit: after nixos-install, the laptop crashed 😄

OK, seems that, after login you need to log as a root and then set the password for the new user. Not so great.

End of the day: I took the configuration straight out from the box, apart of my username, but I couldn't make it work. I got some DBus error that's seems related to gnome somehow, Not very promising.

Since we will follow the idea of: installing more then necessary and then remove/add/replace software with your own, at this point we can just download the virtual box pre-cooked Virtual Machine from the site and try with that. Apparently, I'm not able to start from minimal ISO 😢

The good thing about using the ready-to-go is that you can just:

• Import it into VirtualBox
• Mount the main partition as above
• Generate the configuration
• Install NixOs

So you can skip all the commands about the file system.

Well, I worked on the configuration, but I did a great mistake: I started to change it without regarding if it worked or not. Guess what, the result is that it didn't work and I didn't know why. I assume all the guilty, I should just start from something that works and, VERY SLOWLY, start changing it as I wish.

So what I do now is, let's just apply the configuration I forked from and then let's see what we can do to make it mine 😃

Well, seems that, even just not touching anything from Gabriel's configuration I got:

error: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name ca.desrt.dconf was not provided by any .service files

I tried applying the solution described in here and in other places, but it didn't work. Then I tried with nix-env -i dconf installing the package manually and it seemed to work. Plus, I had to add a couple of lines into the install script since there were some configuration conflicts to solve.

Well, after the restart, XMonad started but I got this new error:

org.freedesktop.DBus.Error.ServiceUnknown: The name org.blueman.Mechanism was not provided by any .service files

And then the screen stays grey. Apparently we need to install more stuff on to our configuration, I'm going to revert the NixOs and try to do the add from here. Good news, the oldest configuration seems to have the XMonad, so I'm not able to login to the system as before. I'll try to see if I can access a terminal from the grub and commit my changes.

Did I just debunked the Reproducibility and Reversibility of NixOs?? (or I just can't make it work)

Let's take a different approach, I will:

• Take the default /etc/nixos/configuration.conf and the home.nix file I created from my previous experiment
• See if everything works
• Keep tweaking the configuration until a satisfactory result

After a little effort in editing this and that, this seems to be the right way to go. The only problem is that, I did quite some changes, I run a switch command and now the virtual machine is frozen. Time for a break.

There are a bad and a good news, the good one is that I restarted into an XFCE environment, the bad is that it doesn't seems to have any software available from the ones I specified into my home.nix and now I encountered this error:

error: attribute 'anything' missing, at /mix/var/nix/profiles/pre-user/root/channels/home-manager/modules/programs/matplotlib.nix

The fun fact is that I can't change it since the file system is read only!! 😠 At least I was able to push all the changes to the repository, so I can retry a fresh install, since that's what we are looking for, it needs to work right from the start (if it ever does)

I'm not that kind of person who stops at first issue, so let's keep trying and trying again.

• I restarted from a new NixOs machine
• I applied the changes following the guideline and I kept track of each command I did.
• I first applied the configuration.nix, installed NixOs, applied home.nix and finally I ran the home-manager. It seems there's a different way of install home-manager in NixOs since you have to be careful about the specific version you are going to use

And now, finally, I'm able to have a simple setup that works in the Virtual Machine!!!! I can now proceed into tweaking the configuration details until I'm fully happy with it. At each step I will just use the Nix configuration to apply all the changes.

commit ← this is the commit that seems to work now ☺

Now that I'm able to comfortably configure the system, I must say it's pretty fast doing so:

• Adding a new software is usually just

adding it to the packages lines

• Dot files are easy to configure and check
• Stuff like environment variables or daemons are built-in the configuration of NixOs or home-manager.

Once you start understanding how things works you move quickly then a bash script. Anyway, you can always fallback to a script for some tasks.

For simplicity I used xfce as window manager, but now that everything seems fine, I really wish to move to a tiling window manager.

I just tried with i3 and I messed up with the configuration as expected. Well, I think it's time to put the NixOs time machine mechanism to the test…and I was able to go back to a previous working configuration of my system, change the configuration and try a different setup, Benkio is happy now!!! 😃

At the end of the day I did some progress, but half of my Virtual Machine snapshots are broken due to bad configuration.

edit: when I say «up to speed» I mean, «most of the time». For example, it took me half a day to setup Firefox extensions using home-manager and nur due to the fact that I needed to apply a package Override and it was not so easy to figure it out.

I think I reached quite a fine initial configuration by now: I just have all the software I need (Emacs and Firefox basically 😃) and I have a basic tiling window manager (i3) with simple configuration to manage windows and so on.

What I will do now is:

• Playing more into the Virtual Machine: trying to develop in it for a bit and do my classic tasks.
• Work more on the startup installation: setup everything from the minimal NixOs as smoothly as possible. Probably creating one or more basic shell scripts.

After a while, when I feel confident I might format my main machine entirely and switch to NixOs. I might add a new section later on in case of relevant updates.