Docker in 2026: install it the way Docker actually recommends

BASIC

Tested for real: I ran every command in this guide top-to-bottom on a fresh Ubuntu 24.04 virtual machine (4 CPUs, 8 GB RAM) on 13 August 2026. Versions at test time: Docker Engine 29.7.2, Docker Compose v5.4.0, containerd 2.3.3, Buildx v0.36.1, on Ubuntu 24.04.4 LTS.

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What you'll end up with

Docker installed from Docker's own package source, the way their documentation says to do it. You will run a real container and see it work. You will also know how to remove every trace of it, because I tested that too.

Hello from Docker!
This message shows that your installation appears to be working correctly.

Who this is for

BASIC. One path, copy-paste-safe, no branching. If you can open a terminal on your Ubuntu server, you can do this.

Time and cost

The commands themselves took under 3 minutes of machine time when I ran them. Allow 20 minutes end to end, including reading and one log-out-and-back-in. Cost: free. About 400 MB of disk space.

Words you'll meet

• Container — a way to run a program in its own sealed box, with everything it needs packed inside. See /basics.
• Image — the frozen template a container starts from. You download an image once; you can run many containers from it.
• Repository — a source your system downloads software from. Ubuntu has its own; here we add Docker's.
• GPG key — a signature file. Your system uses it to check that downloaded packages really came from Docker.
• Daemon — a program that runs in the background. Docker's daemon does the actual work; the docker command talks to it.
• Compose — Docker's tool for describing a whole service in one file. We only check it exists today; it gets its own guide.

Placeholders

Anywhere you see CAPS-WITH-DASHES like YOUR-USERNAME-HERE, swap in your own value. This guide uses one — YOUR-USERNAME-HERE in the group commands near the end; everything else is copy-paste as written.

Before you start

• An Ubuntu 24.04 server you can log into.
• A normal user account with sudo, not root. If you set the server up with my first hour guide, you have this.
• An internet connection on the server.

A note before the first command

If you have seen older Docker guides, many still say apt-key add. Do not use them. apt-key is deprecated and should not be used in new guides. The modern pattern is a keyring file plus signed-by, which is exactly what Docker's own documentation does — and what we do below.

The steps

Step 1 — Clear out any old Docker bits

Ubuntu ships its own, older Docker packages under different names. They clash with the official ones, so Docker's docs say to remove them first. This is Docker's own removal loop, copied exactly.

for pkg in docker.io docker-doc docker-compose docker-compose-v2 podman-docker containerd runc; do sudo apt-get remove -y $pkg; done

Check it worked. On a fresh machine you'll see a string of "not installed" lines — that is the good outcome:

Package 'docker-compose' is not installed, so not removed
Package 'containerd' is not installed, so not removed
0 upgraded, 0 newly installed, 0 to remove and 26 not upgraded.

The important line is 0 upgraded, 0 newly installed, 0 to remove. If it removed real packages instead, that's fine too. That was the point.

Step 2 — Download Docker's signing key

First, refresh the package lists and make sure the two tools we need are present.

sudo apt-get update

sudo apt-get install -y ca-certificates curl

A passing run includes:

ca-certificates is already the newest version (20260601~24.04.1).
curl is already the newest version (8.5.0-2ubuntu10.11).

Your versions may be newer — that's fine.

Now make the folder where Ubuntu keeps signing keys. It may already exist; this command is safe either way.

sudo install -m 0755 -d /etc/apt/keyrings

Download Docker's key into that folder, and make it readable.

sudo curl -fsSL https://download.docker.com/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.asc

sudo chmod a+r /etc/apt/keyrings/docker.asc

Check it worked.

ls -l /etc/apt/keyrings/docker.asc

The important line is:

-rw-r--r-- 1 root root 3817 Aug 13 16:05 /etc/apt/keyrings/docker.asc

The -rw-r--r-- at the start matters — the key is readable by everyone, as apt needs. The three commands before this print nothing on success — silence is normal here.

Step 3 — Tell Ubuntu about Docker's repository

This long command writes one line into a file. The line says: fetch Docker packages from download.docker.com, and only trust them if they're signed by the key we just saved. The $(...) parts fill in your machine's details automatically — no editing needed.

echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/ubuntu $(. /etc/os-release && echo "${UBUNTU_CODENAME:-$VERSION_CODENAME}") stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

Check it worked.

cat /etc/apt/sources.list.d/docker.list

Your output will vary, but look for:

deb [arch=amd64 signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/ubuntu noble stable

Your architecture and codename fill in the amd64 and noble slots; the shape of the line is what matters.

Now refresh the package lists again, so Ubuntu reads that new file.

sudo apt-get update

A passing run includes:

Get:1 https://download.docker.com/linux/ubuntu noble InRelease [48.5 kB]
Hit:2 http://archive.ubuntu.com/ubuntu noble InRelease
[...snipped...]

The load-bearing line is the download.docker.com one. If it's there with no errors, the repository is trusted and live.

Step 4 — Install Docker

Five packages: the engine, the command-line tool, the container runtime, and the Buildx and Compose plugins. This is the exact set Docker's documentation installs.

sudo apt-get install -y docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

In my test this downloaded 102 MB and finished in 20 seconds. On a slower line, expect a few minutes.

Check it worked. Docker starts itself immediately — verify that:

sudo systemctl is-active docker

active

One word, active, is the whole answer.

Step 5 — Run your first container

hello-world is Docker's tiny self-test image. This one command downloads it, runs it, and prints a message from inside the container.

sudo docker run hello-world

You should see something like:

Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world
[...snipped...]
Hello from Docker!
This message shows that your installation appears to be working correctly.
[...snipped...]

The important line is Hello from Docker! — that message was produced inside a container. Docker works.

Step 6 — Drop the sudo (and understand what that costs)

Right now only sudo can talk to Docker. Try it without:

docker ps

The important line is:

permission denied while trying to connect to the docker API at unix:///var/run/docker.sock

The fix is adding yourself to the docker group. But be honest with yourself about what this means: membership of the docker group is effectively root access. Anyone in that group can start a container that mounts the whole disk and read anything on the machine. Docker's own docs say the same. On a personal server that trade is usually fine; on a shared machine, think first — sticking with sudo docker is a valid choice.

sudo usermod -aG docker YOUR-USERNAME-HERE

(Or use $USER and it fills in your name automatically.)

Group changes only apply to new logins. Log out, log back in, then:

Check it worked.

groups

Your output will vary, but look for:

tester docker

The important word is docker at the end of your group list. And now, no sudo needed:

docker run hello-world

Hello from Docker!
[...snipped...]

Step 7 — Confirm Compose came along

The Compose plugin installed in step 4. One check now saves confusion later.

docker compose version

You should see something like:

Docker Compose version v5.4.0

Your version may be newer — that's fine. Note the command is docker compose with a space. The old hyphenated command is legacy; use the plugin form here. If a guide tells you to install docker-compose, that guide is out of date.

Something went wrong?

• You see permission denied ... docker.sock → it means your user isn't in the docker group yet, or you haven't logged out and back in since adding it → log out fully (close the terminal or SSH session) and log back in, then run groups to confirm docker is listed.
• You see groups without docker in an old terminal, but a new login shows it → it means group membership is stamped at login time → any terminal opened before the change won't have it. New login, new powers.
• You see E: Package 'docker-ce' has no installation candidate → it means step 3's repository line didn't take → run cat /etc/apt/sources.list.d/docker.list, compare with the expected output above, then sudo apt-get update and look for the download.docker.com line.

Undo all of this

Tested for real on the same machine, straight after the install. Five commands take you back to a Docker-free system.

Remove the packages and their configuration:

sudo apt-get purge -y docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin docker-ce-rootless-extras

Delete all images, containers and volumes. This is the destructive one — anything you built in Docker goes with it.

sudo rm -rf /var/lib/docker

sudo rm -rf /var/lib/containerd

Remove the repository and key we added:

sudo rm /etc/apt/sources.list.d/docker.list

sudo rm /etc/apt/keyrings/docker.asc

Check it worked.

docker --version

docker: command not found

The refusal is the pass mark.

Optionally, take yourself back out of the (now empty) docker group:

sudo gpasswd -d YOUR-USERNAME-HERE docker

Removing user tester from group docker

Where to go next

• Docker Compose for real: one file, whole service — and the firewall trap — the GOING FURTHER follow-on, where Docker starts earning its keep.
• Official reference: docs.docker.com/engine/install/ubuntu — this guide follows it step for step, with real outputs added.

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Last tested: 13 August 2026 on Ubuntu 24.04.4. Versions: Docker Engine 29.7.2, Compose v5.4.0, containerd 2.3.3, Buildx v0.36.1.