• 2 Posts
  • 19 Comments
Joined 1 year ago
cake
Cake day: July 2nd, 2023

help-circle
  • I recommend starting with ZeroToNix’s docs and then moving on to nixos.wiki, but here is a minimal, working example that I could deploy to a hetzner VPS that only has nix and ssh installed:

    { config, pkgs, ... }: {
      # generated, this will set up partitions and bootloader in a separate file
      imports = [ ./hardware-configuration.nix ];
      zramSwap.enable = true;
      networking.hostName = "miki";
      # configures SSH daemon with a public key so we can ssh in again
      services.openssh.enable = true;
      users.users.root.openssh.authorizedKeys.keys = [ ''ssh-ed25519 AAAAC3NzaC1lNDI1NTE5AAAAIPJ7FM3wEuWoVuxRkWnh9PNEtG+HOcwcZIt6Qg/Y1jka'' ];
      # creates a timmy user with sudo access and wget installed
      users.users.timmy = {
        isNormalUser = true;
        extraGroups = [ "networkmanager" "wheel" "sudo" ];
        packages = with pkgs; [ wget ];
      };
      # open up SSH port
      networking.firewall.allowedTCPPorts = [ 22 ];
      # start nginx, assumes HTML is present at `/var/www`
      services.nginx = {
        enable = true;
        virtualHosts."default" = {
          forceSSL = true;            # Redirect HTTP clients to an HTTPs connection
          default = true;             # Always use this host, no matter the host name
          root = /var/www;        # Set the web root to ser
        };
      };
      system.stateVersion = "22.11";
    }
    

    This sets up a machine, configures the usual stuff like the ssh daemon, creates a user, and sets up an nginx server. To deploy it you would run nixos-rebuild --target-host root@10.0.0.1 switch. Other tools exist (I use colmena but the idea is the same). Note how easy it was to set up nginx! If I was setting Nomad up, I would just do services.nomad.enable = true.

    As you can see some things you will have to learn (the nix language, what the configs are…) but I think it is worth it.


  • I see no one else commented my stack, so I suggest:

    Nomad for managing containers if you want something high availability. Essentially the same as k8s but much much much simpler to deploy, learn, and maintain. Perfect for homelabs imo. Most of the concepts of Nomad translate well to k8s if you do want to learn it later. It integrates really well with Terraform too if you are also hoping to learn that, but it’s not a requirement.

    NixOS for managing the bare metal. It’s a lot more work to learn than say, Debian, but it is just as stable, and all configuration will be defined as code, down to the bootloader config (no bash scripts!). This makes it super robust. You can also deploy it remotely. Once you grow beyond a handful of nodes it’s important to use a config management tool, and Nix has been by far my favourite so far.

    If you really want everything to be infra-as-code, you can manage cloud providers via Terraform too.

    For networking I use wireguard, and configure it with NixOS. Specifically, I have a mesh network where every node can reach every node without extra hops. This is a requirement if you don’t want a single point of failure (hub and spoke) to disconnect your entire cluster.

    Everything in my setup is defined ‘as-code’, immutable, and multi-node (I have 7 machines) which seems to be what you want, from what you say in your post. I’ll leave my repo here, and I’m happy to answer questions!

    My opinions on the alternatives:

    Docker compose is great but doesn’t scale if you want high availability (ie, have a container be rescheduled on node failure). If you don’t want higher availability, anything more than docker might be overkill.

    Ansible and Puppet are alright but are super stateful, and require scripting. If you want immutability you will love Nix/NixOS

    k8s works (I use it at work) but is extremely hard to get right, even for well-resourced infra teams. Nomad achieves the same but with the leanings of having come afterwards, and without the history.


  • I think there are two approaches to infrastructure as code (and even code in general):

    • as steps (ansible, web UI like pihole…)
    • declarative (nix, k8s, nomad, terraform…)

    Both should scale (in my company we use templating a lot) but I find the latter easier to debug, because you can ‘see’ the expected end result. But it boils down to personal preference really.

    As for your case, ideally you don’t write custom code to generate your template (I agree with you in that it’s tedious!), but you use the templating tool of your framework of choice. You can see this example, it’s on grimd (what I forked leng from) and Nomad, but it might be useful to you.

    P.S also added to the docs on the signal reloading here


  • I have a similar use case where I also need my records to change dynamically.

    Leng doesn’t support nsupdate (feel free to make an issue!), but it supports changing the config file at runtime and having leng reread it by issuing a SIGUSR1 signal. I have not documented this yet (I’ll get to it today), but you can see the code here

    Alternatively, you can just reload the service like you do with pihole - I don’t know how quick pihole is to start, but leng should be quick enough that you won’t notice the interim period when it is restarting. This is what I used to do before I implemented signal reloading.

    Edit: my personal recommendation is you use templating to render the config file with your new records, then reload via SIGUSR1 or restart the service. nsupdate would make leng stateful, which is not something I desire (I consider it an advantage that the config file specifies the server’s behaviour exactly)









  • What you described is correct! How to replicate this will depend heavily on your setup.

    In my specific scenario, I make the containers of all my apps use leng as my DNS server. If you use plain docker see here, if you use docker compose you can do:

    version: 2
    services:
     application:
      dns: [10.10.0.0] # address of leng server here!
    

    Personally, I use Nomad, so I specify that in the job file of each service.

    Then I use wireguard as my VPN and (in my personal devices) I set the DNS field to the address of the leng server. If you would like more details I can document this approach better in leng’s docs :). But like I said, the best way to do this won’t be the same if you don’t use docker or wireguard.

    If you are interested in Nomad and calling services by name instead of IP, you can see this tangentially related blog post of mine as well








  • Yep I am using traefik -> nginx. I simply add the traefik tags to the nginx service. I didn’t include that in the example file to keep it simple.

    As for the storage, I use SeaweedFS (has a CSI plugin, really cool, works well with nomad) but as a CSI volume it’s not suitable for backing postgres’ filesystem. The lookups are so noticeably slower that your Lemmy instance will be laggy. So I decided to use a normal host volume, so the DB writes to disk directly, and you can back that up to an S3-compatible storage with this (also cool). Could be SeaweedFS, AWS, Backblaze…

    I think SeaweedFS is suitable for your pictrs storage though, be it through its S3 API (supported by pictrs) or through a SeaweedFS CSI volume that stores the files directly.

    I hope that answers it! Do let me know what you end up with


  • There are dozens of us!

    • nomad fmt was applied already - granted it is not a small easy to read job file, it might be easier to split it up into separate jobs
    • I will look into making this into a Pack - I have never built one because I have never shared my config like this before. I don’t know how popular they are among selfhosters either!

    I think an easy first step would be to contribute a sample job file like this into the Lemmy docs website. Then people can adapt to their setups. I find there is a lot more to configure in Nomad than in Docker compose for example because you stop assuming everything will be in a single box, which changes networking considerably. There is also whether to use Consul, Vault etc.