# 💻 Machine Preparation


# System requirements

📍 *k3s default behaviour is that all nodes are able to run workloads, including control nodes. Worker nodes are therefore optional.*

📍 *If you have 3 or more nodes it is strongly recommended to make 3 of them control nodes for a highly available control plane.*

📍 *Ideally you will run the cluster on bare metal machines.*

| Role             | Cores     | Memory         | System Disk                |
|------------------|-----------|----------------|----------------------------|
| Control          | 4 *(6\*)* | 8GB *(24GB\*)* | 100GB *(500GB\*)* SSD/NVMe |
| Worker           | 4 *(6\*)* | 8GB *(24GB\*)* | 100GB *(500GB\*)* SSD/NVMe |
| *\* recommended* |           |                |                            |


# Debian for AMD64

1.  [Download the latest stable release of Debian](https://cdimage.debian.org/debian-cd/current/amd64/iso-dvd), then follow [this guide](https://www.linuxtechi.com/how-to-install-debian-12-step-by-step) to get it installed.

    Deviations from the guide:

    > ``` txt
    > Choose "Guided - use entire disk"
    > Choose "All files in one partition"
    > Delete Swap partition
    > Uncheck all Debian desktop environment options
    > ```

2.  \[Post install\] Remove CD/DVD as apt source

    ``` sh
    su -
    sed -i '/deb cdrom/d' /etc/apt/sources.list
    apt update
    exit
    ```

3.  \[Post install\] Enable sudo for your non-root user

    ``` sh
    su -
    apt update
    apt install -y sudo
    usermod -aG sudo ${username}
    echo "${username} ALL=(ALL) NOPASSWD:ALL" | tee /etc/sudoers.d/${username}
    exit
    newgrp sudo
    sudo apt update
    ```

4.  \[Post install\] Add SSH keys (or use `ssh-copy-id` on the client that is connecting)

    1.  Add with `ssh-copy-id`

    ``` sh
    ssh-copy-id -i ~/.ssh/id_ed25519 <user>@<host>
    ```

    2.  Add with github

    📍 *First make sure your ssh keys are up-to-date and added to your github account as [instructed](https://docs.github.com/en/authentication/connecting-to-github-with-ssh/adding-a-new-ssh-key-to-your-github-account).*

    ``` sh
    mkdir -m 700 ~/.ssh
    sudo apt install -y curl
    curl https://github.com/${github_username}.keys > ~/.ssh/authorized_keys
    chmod 600 ~/.ssh/authorized_keys
    ```