# Install Ubuntu Server With Autoinstall


### Overview & Core Concepts

> ***TL;DR.*** This guide explains how to automate the installation of **Ubuntu Server 24.04 LTS (Unattended Autoinstall)** using the `auto_install` plugin from **Ventoy** and **Cloud-Init (Subiquity)**. With this method, the OS installation on Mini PCs / Bare-metal Servers can run automatically from start to finish without manual interaction.

- **Scope / Domain:** Automated Server Provisioning, Unattended OS Installation, Homelab / Bare-metal Setup.
- **Tech Stack Related:** Ubuntu Server 24.04 LTS, Ventoy Auto Install Plugin, Cloud-Init / Subiquity (`user-data` & `meta-data`), OpenSSL, LVM.
- **Target Use Case:** Automated local server / Mini PC setup via USB Flash Drive without the need to manually enter hostname, username, password, or network configurations during the boot process.

---
### Setup & Initial Configuration

#### 1. Ventoy Flash Drive Folder Structure

Place the Ubuntu Server ISO and the autoinstall configuration folders on the root of a Ventoy-installed USB Flash Drive with the following structure:

```text
/ (Ventoy Flash Drive Root)
├── ubuntu-24.04-live-server-amd64.iso  <-- Ubuntu Server ISO file
└── ubuntu/
    ├── autoinstall/
    │   ├── meta-data                   <-- Initial instance/hostname identity
    │   └── user-data                   <-- Cloud-config & installation automation script
    └── ventoy/
        └── ventoy.json                 <-- ISO mapping to autoinstall script
```

#### 2. Generating Encrypted Password (SHA-512)

By default, `user-data` requires a password in SHA-512 hash format. Run the following command in a Linux/macOS terminal to generate the password hash:

```bash
openssl passwd -6 "YourStrongPassword"
```

> **Output Result:** `$6$xxxxxx$...` (Copy this hash string into the `identity.password` field in `user-data`).

---
### Usage & Code Snippets

#### 1. Mapping Configuration File: `ventoy.json`

Location: `/ubuntu/ventoy/ventoy.json`

This file tells Ventoy to automatically load the `user-data` template when the Ubuntu Server ISO is selected.

```json
{
  "auto_install": [
    {
      "image": "/ubuntu-24.04-live-server-amd64.iso",
      "template": "/ubuntu/autoinstall/user-data"
    }
  ]
}
```

---

#### 2. Instance Metadata File: `meta-data`

Location: `/ubuntu/autoinstall/meta-data`

```yaml
instance-id: ubuntu-autoinstall
local-hostname: changeme
```

---

#### 3. Autoinstall Main Config File: `user-data`

Location: `/ubuntu/autoinstall/user-data`

```yaml
#cloud-config
autoinstall:
  version: 1

  apt:
    geoip: true
    preserve_sources_list: false
    primary:
    - arches: [ amd64, i386 ]
      uri: http://archive.ubuntu.com/ubuntu
    - arches: [ default ]
      uri: http://ports.ubuntu.com/ubuntu-ports

  identity:
    hostname: changeme
    realname: Changeme
    username: changeme
    password: changeme # Replace with output from: openssl passwd -6 "YourStrongPassword"

  ssh:
    install-server: true
    allow-pw: true
    authorized-keys: []

  keyboard:
    layout: us

  locale: en_US

  storage:
    layout:
      name: lvm
      sizing-policy: all

  network:
    version: 2
    ethernets:
      enp0s31f6:
        dhcp4: true

    wifis:
      wlp3s0:
        dhcp4: true
        access-points:
          "Your WiFi SSID":
            password: "yourwifipassword"

  packages:
  - curl

  late-commands:
  - curtin in-target -- apt update
  - curtin in-target -- systemctl enable ssh
```

---
### Troubleshooting & Known Issues

| Problem / Error | Cause | Solution / Workaround |
| --------------- | ----- | --------------------- |
| **LVM disk capacity truncated (only ~100GB)** | By default, the Ubuntu Subiquity installer with `storage.layout.name: lvm` only allocates a max of **100 GB** for the Logical Volume (`ubuntu-lv`), while the rest of the disk is left *unallocated*. | Run the following commands on the server after installation completes to extend the LV to the remaining disk space:<br>`sudo lvextend -l +100%FREE /dev/ubuntu-vg/ubuntu-lv`<br>`sudo resize2fs /dev/ubuntu-vg/ubuntu-lv` |
| **Network Connection / Interface Not Detected** | Network interface names in `user-data` (`enp0s31f6` / `wlp3s0`) are hardcoded and might differ on each PC hardware. | Adjust the ethernet/Wi-Fi interface names according to the target device, or use generic DHCP/netplan configuration after the OS is installed. |
| **SSH Login Failed with Password Hash** | Entering plain-text password directly into the `identity.password` field without OpenSSL encryption. | Always generate a SHA-512 hash using `openssl passwd -6 "YourPassword"` before inserting it into `user-data`. |
| **Ventoy Does Not Automatically Load Autoinstall** | The ISO or template path in `ventoy.json` does not match the physical location on the USB Flash Drive. | Ensure the ISO and `user-data` template file locations in `ventoy.json` start with a slash `/` from the flash drive root. |

---
### Best Practices & Pitfalls

- **Do:**
  - Use `openssl passwd -6` to encrypt user passwords before saving `user-data`.
  - Perform LVM disk expansion (`lvextend`) post-installation if using disk capacity > 100GB.
  - Verify network interface name compatibility (Ethernet / Wi-Fi) on target hardware.
- **Don't:**
  - Save plain-text passwords in the `user-data` file.
  - Change the `ventoy.json` folder location from the default path `/ventoy/ventoy.json` or `/ubuntu/ventoy/ventoy.json`.

---
### References & Related Links

- [Ventoy Auto Install Plugin Documentation](https://www.ventoy.net/en/plugin_autoinstall.html)
- [Ubuntu Canonical Subiquity Autoinstall Reference](https://canonical-subiquity.readthedocs-server.ubuntu.com/)
- [Cloud-Init Documentation](https://cloudinit.readthedocs.io/)