To Systemd or not to Systemd

[2q2code]

That is the question. 😅

I am a fan of systemd. I know it gets a bunch of hate but with my Arch setups it has done a lot more good than bad.

I wanted to know, is there a significant resource or performance benefit to justify the effort of changing Komodo and/or periphery from docker containers to native-run binaries?

My original perspective was "well, they're FOR Docker, might as well run them there", but I would appreciate input from the 🐴 👄.

[mbecker20]

With Container, you have to deal with the file system seperation, which leads to several complications:

• Say you make a Repo Resource in Komodo, and specify /home/🐴/👄 as the clone path. You click button to clone it and check your host for the repo. But oh wait, its not there! Is Komodo broken? No, its because you cloned it inside the container, you didn't mount /home/🐴:/home/🐴. This issue has come up several times in various forms, commonly for Files on Server mode Stacks.

• You like to use relative file paths in your compose file mounts. When Komodo deploys a Stack, it sends command to Periphery, and Periphery does some setup and runs a shell command docker compose ..... You can see the breakdown of the steps if you click on the Deploy Stack update. If Periphery is running inside Container, the shell command is also inside the container. So then docker compose is running inside the container. If you were docker compose, wouldn't you be confused about which relative directory to mount, is it relative to the container filesystem or host filesystem? The discussion Are relative paths for mounting functioning? #180 has the solution, there is a solution, but you have to know about it, understand it, and edit your config files to compensate.

• You have multiple Disks mounted. Without additional configuration, Periphery inside container won't pick up the disks for usage tracking / alerting. You also need to mount them like -v /mnt/example:/mnt/example:ro.

With systemd, Periphery runs on the host, with no seperation with the host filesystem, making all these confusing file system mapping issues go away. The fact is, Periphery is designed to communicate directly with the system, so the container separation gets in the way.

I can see why this requires more trust in the application to operate outside container, but also note that you can leverage the User option in service file, and have the Periphery binary run as a user you configure, with non root system priviledges. If you then try cloning a repo in /etc/docker or another protected directory, it will fail with permissions issue. You can permission the user only to have write access to a specific folder, something like that. For my personal homelab, I just use my linux user and use systemctl --user start periphery. See https://github.com/mbecker20/komodo/tree/main/scripts#user.

So overall, I prefer systemctl to avoid the file system seperation issues I mentioned, and would recommend this where possible. However I also have a pretty good understanding of systemctl in general and can get it to do what I want about as easily as I can containers. If you don't already know systemctl / linux user permissioning, it may be easier for you to just deal with the container issues though.

It sounds like you like systemctl, in your case I'd say yeah, use systemctl, and do the deploy with Ansible. Like I mentioned before, its fully automatable as well, and you can do it as a Komodo Stack deployed on git push.

- name: Deploy Periphery
  hosts: periphery
  tasks:
    - name: Ensure config dir
      file:
        path: "{{ HOME }}/.config/komodo"
        state: directory
        mode: '0755'

    - name: Download config
      get_url:
        url: https://your.git.provider/komodo/periphery/raw/branch/main/periphery.config.toml
        dest: "{{ HOME }}/.config/komodo/periphery.config.toml"
        mode: '0644'

    - name: Ensure service dir
      file:
        path: "{{ HOME }}/.config/systemd/user"
        state: directory
        mode: '0755'

    - name: Download service
      get_url:
        url: https://your.git.provider/komodo/periphery/raw/branch/main/periphery.service
        dest: "{{ HOME }}/.config/systemd/user/periphery.service"
        mode: '0644'

    - name: Ensure bin dir
      file:
        path: "{{ HOME }}/.local/bin"
        state: directory
        mode: '0755'

    - name: Download bin
      get_url:
        url: https://github.com/mbecker20/komodo/releases/download/v1.16.12/periphery-x86_64 # or -aarch64
        dest: "{{ HOME }}/.local/bin/periphery"
        mode: '0755'

    - name: Restart periphery
      shell: |
        systemctl --user daemon-reload
        systemctl --user restart periphery
      args:
        executable: /bin/bash

services:

  ansible:
    image: alpine/ansible
    user: 1000:1000
    network_mode: host
    working_dir: /project
    command: ansible-playbook -i hosts.ini playbook.yaml --extra-vars "HOME=$HOME"
    volumes:
      - /etc/passwd:/etc/passwd
      - $HOME/.ssh:$HOME/.ssh
      - ./.ansible:$HOME/.ansible
      - ./hosts.ini:/project/hosts.ini
      - ./playbook.yaml:/project/playbook.yaml

🦎