How to Install Ubuntu Server on a Raspberry Pi (2026 Guide)

Want to build a homelab or run a serious Raspberry Pi project? Then ditch the SD cards and get ready to install Ubuntu Server onto a USB drive using Raspberry Pi Imager. Whether you’re building a multi-node Pi cluster (like we are), running self-hosted apps, or connecting to Azure — this is step one.

This guide works for Raspberry Pi 4 and 5. The steps are the same whether you write the image to a USB SSD, a USB flash stick or an SD card, but for anything that runs 24/7 use a USB SSD (or an NVMe drive on a Pi 5). A USB flash stick is not the durable option it looks like: it uses the same kind of cheap flash as an SD card and wears out the same way. More on that below. Let’s get into it.

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How Do You Install Ubuntu Server on a Raspberry Pi? (Short Answer)

Flash Ubuntu Server 26.04 LTS (or 24.04 LTS) to a USB SSD with Raspberry Pi Imager, preconfigure the hostname, user and SSH key in the Imager’s settings before writing, then boot and connect over SSH – no monitor needed. Booting from an SSD is strongly preferred over microSD or a USB flash stick for reliability. The full walkthrough below covers first-login hardening too.

🧰 What You’ll Need

• Raspberry Pi 4 or 5
• A USB SSD (a SATA SSD in a USB 3 adapter is fine), or for a quick test only, a 32GB or larger USB stick or SD card
• Raspberry Pi Imager (free from raspberrypi.com)
• A laptop or desktop to run the Imager
• Your Wi-Fi SSID & password (if using wireless)
• A hostname and password you want to use

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📥 Step 1: Open Raspberry Pi Imager

After downloading and opening Raspberry Pi Imager:

1. Click “Choose Device” and select your model (we’re using Raspberry Pi 4).
2. Click “Choose OS”
   • Scroll to “Other general purpose OS”
   • Choose “Ubuntu”, then pick Ubuntu Server 26.04 LTS (64-bit), the current LTS (released April 2026). Ubuntu Server 24.04 LTS (64-bit) is still listed and supported.
   • Planning to use Azure Arc or other Microsoft integrations? Check Microsoft’s supported operating system list for the agent first; if 26.04 is not on it yet, use 24.04 LTS.
   • Canonical notes that recent Ubuntu releases need a minimum bootloader (EEPROM) date on the Pi 4 and Pi 5, so update the bootloader first if the Pi has not been updated in a while (see the gotchas below).

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⚙️ Step 2: Set Up Advanced Configuration

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💾 Step 3: Image Your USB (or SD Card)

1. Click “Choose Storage” and select your USB SSD (or stick, or SD card)
2. Hit “Write”
3. Accept any prompts about data being erased
4. Sit back for a couple of minutes (1–5 mins depending on your PC speed)

🎉 That’s it — once it’s done, eject the drive and plug it into your Raspberry Pi.

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✅ Final Step: Boot Your Pi

Plug in your imaged USB (or SD card) and power on your Pi.

• If your config had SSH enabled, you’re ready to log in remotely.
• If you used Wi-Fi, give it a minute to connect before trying SSH.
• You’ll now have a clean, lightweight Ubuntu Server install — ready to build, host, automate, or join your cluster!

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📦 Bonus: Why USB Over SD?

A USB SSD is faster and far more durable than an SD card, which matters in clusters and anything server-like. A USB flash stick is not: it is faster than most SD cards but wears out in the same way, so it is not the upgrade it appears to be. The section below explains why.

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🔗 Links & Resources

• 🛒 Pi Cluster Shopping List
• Raspberry Pi Imager (free Download)
• Ubuntu Repo

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From the homelab: USB Boot Means an SSD, Not a USB Stick

SD cards fail. It is not a question of if, it is when. But moving to USB boot only fixes that if what you plug in is an SSD. My K3s cluster of Raspberry Pi 4s boots from USB flash sticks, and they are wearing out the same way SD cards do: one node is dead and the cluster’s control-plane node is throwing disk medium errors. A busy Kubernetes node (etcd in particular) writes constantly, and a flash stick has nowhere near the wear levelling or spare capacity of an SSD. If you are building something you want to keep running, boot it from an SSD.

Why USB Boot Over SD Cards?

MicroSD cards were designed for cameras and phones — devices that write data occasionally and read it a lot. A server OS is the opposite: constant writes for logs, databases, temp files, swap, and container layers. SD cards have a limited number of write cycles, and a busy Pi will burn through those cycles faster than most people expect.

Here is what you actually gain by switching to USB boot:

• Reliability. SSDs are built for sustained read/write workloads, with a proper controller, wear levelling and spare capacity. SD cards and USB flash sticks are built for occasional writes, and a busy Pi can wear one out within months.
• Speed. The difference is not subtle. Sequential read speeds on a decent USB SSD are 300-400 MB/s compared to 40-90 MB/s on a fast SD card. Boot times drop noticeably. Docker image pulls are faster. Anything that touches disk — which is everything — benefits.
• Longevity. Even a budget SSD comes with a published write endurance rating (a 120GB Kingston A400 is rated for 40TB written, and bigger drives for more). Most microSD cards and USB flash sticks carry no endurance rating at all. For a device running 24/7 as a server, this matters.
• Cost. A small SATA SSD plus a USB-to-SATA adapter costs a fraction of the Pi itself. Flash prices have moved a lot recently, so check current prices, but this is still the cheapest reliable option.

What You Need for USB Boot

The hardware list is short and cheap:

• Raspberry Pi 5 (or Pi 4 — both support USB boot natively). The Pi 5 supports USB boot out of the box. The Pi 4 may need a one-time firmware update via SD card to enable USB boot — more on that in the gotchas section below.
• A USB SSD. Two main options:
  • SATA SSD + USB-to-SATA adapter: A 120GB Kingston A400 or similar budget SSD plus a Sabrent or StarTech USB 3.0 to SATA adapter. This is the cheapest reliable option.
  • NVMe SSD + NVMe HAT (Pi 5 only): Faster than SATA, but requires a Pi 5 compatible NVMe HAT/base board. The official Raspberry Pi M.2 HAT+ works well.
  • Not a USB flash stick if the Pi will run around the clock. See above.
• A computer to flash the image. Any laptop or desktop running Raspberry Pi Imager.

You do not need a large SSD. Unless you are storing media files directly on the Pi, 120GB is more than enough for the OS, Docker, and a dozen containers. If you need more storage later, you can always mount a network share or add a second drive.

What Each Step Actually Does

The imaging process above uses Raspberry Pi Imager to write Ubuntu Server to your USB drive. Here is what is happening under the surface, so you understand the process rather than just following commands blindly:

• Choosing the device model tells the Imager which bootloader configuration to write. Pi 4 and Pi 5 have different boot processes, and the Imager adjusts accordingly.
• Choosing the OS downloads the selected Ubuntu Server image (or uses a cached copy) and prepares it for the target architecture (ARM64 for all modern Pis).
• Advanced configuration (hostname, SSH, Wi-Fi, username) writes a cloud-init configuration to the boot partition. On first boot, Ubuntu reads this config and applies it automatically — setting your hostname, creating your user, enabling SSH, and connecting to Wi-Fi. This is why you can SSH in immediately without ever connecting a monitor.
• Writing the image partitions the USB drive, writes the boot partition and root filesystem, and applies the cloud-init config. The verification step reads back what was written to confirm there were no errors.

When you plug the USB drive into your Pi and power it on, the Pi’s bootloader detects the USB device, loads the kernel from the boot partition, and hands off to Ubuntu’s init system. Cloud-init runs on first boot, applies your configuration, and within a couple of minutes you have a fully configured Ubuntu Server ready for SSH.

Gotchas and Troubleshooting

USB boot is reliable once it is working, but there are a few things that catch people out:

• Not all USB adapters work. Some cheap USB-to-SATA adapters have issues with UAS (USB Attached SCSI), which is the protocol the Pi uses for USB storage. If your Pi will not boot from a USB drive, the adapter is the most likely culprit. The Sabrent EC-SSHD and StarTech USB3S2SAT3CB are both known to work reliably. If in doubt, check the community compatibility lists.
• Pi 4 firmware update. The Pi 5 supports USB boot out of the box. Early Pi 4 boards shipped with firmware that booted from SD card only, and Canonical lists a minimum bootloader date for recent Ubuntu releases on both models. If your Pi 4 will not boot from USB, you need to update the bootloader firmware. Flash Raspberry Pi OS to an SD card, boot from it, run sudo rpi-eeprom-update -a, then reboot. After the firmware update, the Pi 4 will boot from USB natively.
• Power supply. An SSD draws more power than an SD card. If you are using a marginal power supply, adding an SSD can push it over the edge. The Pi 5 wants a 5V 5A (27W) USB-C supply. The Pi 4 wants 5V 3A (15W). Using the official Raspberry Pi power supplies avoids this issue entirely.
• First boot takes longer. Cloud-init runs on the first boot and applies all your configuration. This can take 1-3 minutes. Do not panic if the Pi seems unresponsive after first power-on. Wait a few minutes, then try to SSH in.
• Wi-Fi takes a moment. If you configured Wi-Fi in the Imager settings, the Pi needs to connect to your network before you can SSH in. This adds another 30-60 seconds after boot. If you can use Ethernet for the initial setup, it is faster and more reliable — you can always configure Wi-Fi later.