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1.2 Operating system

We use Ubuntu Server 26.04.1 LTS ("Resolute Raccoon"): a long-term-support release with five years of security updates, a minimal footprint and no graphical desktop.

Download and verify the image

On your regular computer, open Tor Browser, so these downloads go through Tor too. Download into one folder:

Then verify them. (The large ISO can take a while over Tor; that's normal.)

# Import Ubuntu's CD image signing key
gpg --show-keys ubuntu-cdimage.asc
gpg --import ubuntu-cdimage.asc

# Verify that the checksum file is signed by Ubuntu
gpg --keyid-format long --verify SHA256SUMS.gpg SHA256SUMS

# Check the ISO against the signed checksum file
sha256sum --check --ignore-missing SHA256SUMS

Install GnuPG first (GPG Suite or brew install gnupg), then:

gpg --show-keys ubuntu-cdimage.asc
gpg --import ubuntu-cdimage.asc
gpg --keyid-format long --verify SHA256SUMS.gpg SHA256SUMS
shasum -a 256 --check --ignore-missing SHA256SUMS

Install Gpg4win, then in PowerShell:

gpg --show-keys ubuntu-cdimage.asc
gpg --import ubuntu-cdimage.asc
gpg --keyid-format long --verify SHA256SUMS.gpg SHA256SUMS
Get-FileHash .\ubuntu-26.04.1-live-server-amd64.iso -Algorithm SHA256
Select-String "ubuntu-26.04.1-live-server-amd64.iso" SHA256SUMS

The two hashes printed by the last two commands must be identical (PowerShell prints its hash in capitals; that's fine).

Validation

gpg --show-keys must show this fingerprint, on the line below pub, before you import the key:

843938DF228D22F7B3742BC0D94AA3F0EFE21092

Then you should see:

gpg: Good signature from "Ubuntu CD Image Automatic Signing Key (2012) <cdimage@ubuntu.com>" [unknown]
ubuntu-26.04.1-live-server-amd64.iso: OK

The warning "This key is not certified with a trusted signature" is expected: it only means you haven't personally signed Ubuntu's key.

Danger

If you see BAD signature, or the ISO check doesn't say OK, delete the files and download them again. Don't install from an image that fails these checks.

Write the USB stick

Use balenaEtcher, Ventoy or dd to write the ISO to the USB stick. Writing erases everything on the stick.

Using dd on Linux

Find the stick's device name with lsblk (for example /dev/sdb), and double-check it: dd overwrites whatever you point it at. 

sudo dd if=ubuntu-26.04.1-live-server-amd64.iso of=/dev/sdX bs=4M status=progress oflag=sync

Install

Boot the node from the USB stick (usually F12, F10 or Esc at power-on opens the boot menu) and follow the installer:

  1. Language and keyboard: your choice.
  2. Type of install: Ubuntu Server (minimized) is fine. Check Search for third-party drivers only if your network card needs it.
  3. Network: use the wired interface and DHCP. You'll pin the address in your router in 1.3.
  4. Storage: Use an entire disk, on the SSD. With a single drive, untick Set up this disk as an LVM group to keep things simple.
  5. Profile:
    • Your name: anything
    • Server name: monerobox
    • Username: nodeadmin (Ubuntu reserves admin, so it can't be used)
    • Password: Password [A]
  6. Ubuntu Pro: skip.
  7. SSH: tick Install OpenSSH server. Don't import any keys yet.
  8. Featured snaps: install none.

When it finishes, remove the USB stick and choose Reboot now.

Validation

Log in once at the node's console as nodeadmin, then check the system:

lsb_release -d
uname -m
df -h /

Expected output, roughly:

Description:    Ubuntu 26.04.1 LTS
x86_64
Filesystem      Size  Used Avail Use% Mounted on
/dev/nvme0n1p2  1.8T  5.1G  1.7T   1% /

The Size of / should be close to your SSD's full size. If it's much smaller, see the first item under Troubleshooting.

From here on you continue from your regular computer.

Troubleshooting

The root filesystem is much smaller than my SSD

You left LVM enabled in the storage step. Ubuntu's installer then gives the root volume only part of the disk and leaves the rest unallocated. Grow it to use all free space: 

sudo lvextend -r -l +100%FREE /dev/ubuntu-vg/ubuntu-lv
df -h /
-r also grows the filesystem, so no reboot is needed.

The PC doesn't boot from the USB stick
  • Use the boot menu key shown at power-on (often F12, F11, F10 or Esc), not the normal boot order.
  • In the BIOS/UEFI settings, make sure USB boot is enabled. If the stick still isn't listed, disable Secure Boot temporarily, or rewrite the stick with a different tool.
The installer finds no network

Plug in an Ethernet cable before starting the installer. If the network card still isn't detected, tick Search for third-party drivers in step 2.