Server Setup: App Server

1. Preparation & Media Creation

A. Download ISO Get the Small Installation Image (Netinst).

Architecture

For Lenovo M920q/M70q nodes, ensure you download the amd64 ISO.

B. Flash to USB Use BalenaEtcher, Rufus, or dd to write the ISO to a USB drive (4GB+).

2. BIOS / UEFI Configuration

Mini PCs often ship with settings optimized for Windows. Adjust these for a Linux server.

Enter BIOS: Power on and rapidly tap the setup key (F1 for Lenovo).
Secure Boot: Set to Disabled.
Reasoning: While Debian supports Secure Boot, disabling it prevents headaches with third-party drivers (Nvidia) or unsigned kernel modules later.
Power Behavior: Set "After Power Loss" to Power On.
Boot Order: Prioritize the USB drive.

3. Installation Process

Boot from USB. The Debian installer uses a classic text-based interface. Navigate with Arrow Keys, select with Enter, and toggle options with Space.

A. Initial Settings

Install: Select Graphical Install (easier) or Install (text-only).
Language/Location/Keyboard: Select defaults.
Hostname: vanth-node-01 (or your preference).
Domain Name: Leave blank (unless you have a local domain).

B. User & Password (Crucial)

Sudo Configuration

Leave the 'Root password' field BLANK.

If you leave the root password blank, the installer will automatically install `sudo` and add your new user to the sudo group. If you set a root password now, you will have to manually configure sudo later.

Full name / Username: Enter your details (e.g., username).
Password: Set a strong password for this user.

C. Partitioning

Method: "Guided - use entire disk and set up LVM".
Partition Scheme: "All files in one partition" (easiest for beginners).
Confirm: Select "Finish partitioning and write changes to disk" -> Yes.

D. Software Selection (Tasksel)

The installer will install the base system and then ask for additional software.

Scan extra media? No.
Package Manager: Select a mirror close to you (e.g., deb.debian.org).
Software selection:
[ ] Debian desktop environment (Uncheck this)
[ ] GNOME (Uncheck this)
[x] SSH server (Check this)
[x] Standard system utilities (Check this)

4. Post-Install Configuration

Remove the USB and reboot. Log in via the physical terminal one last time to get the IP.

A. Network Configuration (Static IP)

Debian uses /etc/network/interfaces by default, not Netplan.

Check Interface Name:

ip link
# Look for eno1, eth0, or enp3s0

Edit Config:
```
sudo nano /etc/network/interfaces
```

Modify: Replace allow-hotplug eno1 and iface eno1 inet dhcp with:

# The primary network interface
auto eno1
iface eno1 inet static
    address 192.168.1.50/24
    gateway 192.168.1.1
    # DNS servers
    dns-nameservers 1.1.1.1 8.8.8.8

Apply:
```
sudo systemctl restart networking
```

B. Connect via SSH

Switch to your main PC terminal:

ssh username@192.168.1.50

C. Update System

sudo apt update && sudo apt upgrade -y

5. Quality of Life & Security

A. Install QEMU Guest Agent (If VM)

If this is running as a VM inside Proxmox:

sudo apt install qemu-guest-agent -y
sudo systemctl enable --now qemu-guest-agent

B. Prevent Sleep

Prevent the Mini PC from suspending when idle:

sudo systemctl mask sleep.target suspend.target hibernate.target hybrid-sleep.target

C. Install Vital Tools

Debian "Standard Utilities" is very barebones.

sudo apt install curl wget git htop vim tmux -y

Troubleshooting

"Username is not in the sudoers file": You likely set a root password during install.
Fix: Switch to root (su -), then run usermod -aG sudo your_username. Reboot.
SSH Connection Refused: Check if the service is running (sudo systemctl status ssh). If missing, sudo apt install openssh-server.
DNS failures: Check /etc/resolv.conf. It should contain nameserver 1.1.1.1. If not, your static IP config in /etc/network/interfaces might have a syntax error.