From 0e79a9fe0cb628f0492bb6ba0d02a27e803a8cce Mon Sep 17 00:00:00 2001 From: Marc Coquand Date: Sat, 20 Jan 2024 16:57:53 -0600 Subject: Using Git to Deploy Nix Configurations --- posts/git-to-deploy.njk | 63 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) create mode 100644 posts/git-to-deploy.njk (limited to 'posts/git-to-deploy.njk') diff --git a/posts/git-to-deploy.njk b/posts/git-to-deploy.njk new file mode 100644 index 0000000..244e987 --- /dev/null +++ b/posts/git-to-deploy.njk @@ -0,0 +1,63 @@ +--- +layout: post.njk +title: Using Git to Deploy Nix Configurations +tags: post +date: 2024-01-20 +--- + +

Lately I have been learning Nix, which is configured using a +declarative programming language. What is nice about that is that allows +us to reproduce a system very easily. However, I googled around and +tried to figure out how to easily deploy my config from a local machine +to a Nix machine. I started off SSHing into the machine and making edits +using nano in the config, but it’s tedious and I’d rather use my local +machine to change the configurations. There is also little advantage to +having a declarative config if I can’t reuse it elsewhere.

+

There are tools out there like deploy-rs +and Nixops. I found them a +bit overkill for my need, which was just to make changes to a personal +development machine, so I came up with a script to make the setup easy. +It makes use of git, and levarages hooks to validate and apply changes with a simple push. In the end, it creates a workflow similar to Heroku. Here is what the script looks like, which you can run +on a new machine with a fresh Nix installation:

+
# Start of by adding git to our configuration.nix, we will levarage this to
+# be able to easily make changes to our machine without SSH.
+sed -i 's/}/  programs.git.enable = true;\n}/g' /etc/nixos/configuration.nix
+
+# Rebuild nix so we have git available
+nixos-rebuild switch
+
+# Set up a git repository where our nixos configuration lives
+cd /etc/nixos
+git init
+
+# Change branch name to main instead of master
+git branch -m main
+
+# Add existing config and commit
+git add .
+git commit -m "Initial commit"
+
+# Allow us to push changes to our machine and have those changes immediately reflected in the files
+git config receive.denyCurrentBranch updateInstead
+
+# Add a git hook to validate incoming changes
+echo -e '#!/bin/sh \nnixos-rebuild dry-run' > /etc/nixos/.git/hooks/pre-receive
+
+# Make the hook executable
+chmod +x /etc/nixos/.git/hooks/pre-receive
+
+# Add a git hook to apply the changes afterward
+echo -e '#!/bin/sh \nnixos-rebuild switch' > /etc/nixos/.git/hooks/post-receive
+
+# Make the hook executable
+chmod +x /etc/nixos/.git/hooks/post-receive
+

Once set up, you can clone the repo on your local computer:

+
git clone root@your-machine:/etc/nixos
+

And if you’d like to set up a backup on Sourcehut, you can do so easily:

+
git remote add backup git@git.sr.ht:~username/reponame
+git push backup main
+

This script can be ran on a new machine. I used Nixos-infect +to setup NixOS on a VPC that I rent on Hetzner cloud.

-- cgit v1.2.3