Installing Ubuntu via Minimal ISO: Build Only What You Need

Most Ubuntu installations come packed with unnecessary software. If you've ever provisioned a VM or physical server and immediately spent time uninstalling GNOME games or PulseAudio, you know the cost of bloat: wasted disk, extra services, broader attack surface. Using the minimal ISO (~70 MB), you assemble Ubuntu on your terms—essential, tailored, and efficient.

Minimal ISO: What It Really Is

The Ubuntu minimal ISO isn’t just “smaller.” It leverages network-based installation, pulling only what you select from current Ubuntu repositories (e.g., 22.04 LTS). No pre-built desktop environment. No kitchen sink. You start with a base root filesystem and critical boot components, adding packages as needed. If your Ethernet drivers aren’t in mainline, bring a dongle—or plan for a headache.

Why Choose Minimal Over Full ISO?

Critical reason: less attack surface and no unwanted daemons.

Workflow: Deploying Ubuntu via Minimal ISO

Assume: Ubuntu Server 22.04 LTS, x86_64 hardware, regular Ethernet.

1. Download Minimal ISO

Current Ubuntu minimal ISO:
https://help.ubuntu.com/community/Installation/MinimalCD

Example for 22.04 (Jellyfish):
mini.iso (note: SHA256-check your download)

2. Write Minimal ISO to USB

• Windows: Rufus (write-as-ISO mode)
• Linux/macOS: dd (or cp for some USB drives)

sudo dd if=mini.iso of=/dev/sdX bs=4M status=progress conv=fsync

Replace /dev/sdX—double-check with lsblk or fdisk -l.
Tip: conv=fsync reduces chance of incomplete writes.

3. Boot Target Machine

Plug USB in.
Interrupt boot (F12/F10/Del—varies) to select your install media.

4. Network Initialization

Minimal ISO needs active network during install—wired is smooth, WiFi can be non-trivial (missing firmware; think iwlwifi). For WiFi, be ready to supply firmware blobs via secondary USB.

5. Partitioning

• Guided (LVM recommended—enables snapshots and later resize)
• Manual (for custom RAID setups or non-standard layouts)

Typical error for full disk encryption (if you set a weak password):

ERROR: The supplied passphrase is too short

Set at least 8 characters; save your luks header backup.

6. Base System Installation

Configure:

• Root/primary user
• Hostname (minimal-X avoids ambiguity in multi-server environments)
• Mirror selection (default OK if standard geo/fast path is available)

7. Software Selection

Don’t select “Ubuntu Desktop” unless you want the regular GUI stack.

Minimal initial stack for servers:

• [x] standard system utilities
• [x] OpenSSH server (optional, but without it remote access is a pain)
• [] Ubuntu desktop

Tip: For true minimal, skip everything—the resulting install drops you at a shell. You’ll need to sudo apt update && sudo apt install everything by hand.

8. Bootloader and Reboot

Install GRUB to /dev/sda (usually safe).

Known issue: On some laptops with Secure Boot, GRUB may fail without shim—disable Secure Boot or preload required drivers before install.

Post-Install: Real-World Examples

Install a lightweight desktop (Xfce):

sudo apt update
sudo apt install xfce4 lightdm

Note: Xfce is reasonably light (~250 MB after dependencies), but still brings in layers (Xorg, session manager).

Minimum viable dev environment:

sudo apt update
sudo apt install build-essential git curl vim

Non-obvious Details

• Mirror Choice: Custom mirror can drastically reduce install time, especially on constrained bandwidth—edit /etc/apt/sources.list post-install if regional mirrors misbehave.

• IPv6: If using minimal ISO in an enterprise VLAN segment with no IPv6, pre-emptively disable via kernel command line, or expect odd apt failures like:

  Temporary failure resolving 'archive.ubuntu.com'
  

• SSH vs. local console: With only “standard utilities” installed, you must manually install OpenSSH if remote, no way around this. Missed it? Mount root disk elsewhere to chroot and install.

Side Note: Alternatives

For custom hypervisor images (e.g., KVM, VMware), debootstrap or cloud-init images can be leaner still, but minimal ISO is quickest path for on-prem, non-cloud workloads.

No installer is perfect. Minimal ISO is sometimes unforgiving—hardware requiring proprietary drivers or manual firmware can stall deployment. Yet, for controlled infrastructure, this method is the foundation of stable, predictable systems.

Summary Table:

For environments where you can't afford surprises, and every service counts, building up from the minimal ISO is worth the initial effort.