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.