Featured · 21 August 2026 · 6 min read
Install Docker Engine from Docker’s official apt repository on Ubuntu 20.04+, verify the daemon with systemctl, and run your first hello-world container.
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Docker packages applications into lightweight containers so you can run the same stack on a laptop, a CI runner, or a production host. This guide shows how to install Docker on Ubuntu from Docker’s official apt repository, what each command should print, and how to run your first containers.
Install steps follow Docker’s current apt repository flow (GPG key +
sources.listentry). For a long-form community walkthrough of the same topic, see DigitalOcean’s Ubuntu Docker tutorial.
docker-ce, CLI, containerd, Buildx, and Composehello-worldsudodocker commands with sample outputsudo userapt can reach download.docker.comsudo apt update
Expected output (truncated; package counts vary):
Hit:1 http://archive.ubuntu.com/ubuntu jammy InRelease
Get:2 http://security.ubuntu.com/ubuntu jammy-security InRelease [129 kB]
Fetched 2,184 kB in 2s (1,012 kB/s)
Reading package lists... Done
Building dependency tree... Done
Then install packages apt needs for HTTPS repositories:
sudo apt install ca-certificates curl gnupg
Expected output (when packages are new):
Reading package lists... Done
Building dependency tree... Done
The following NEW packages will be installed:
ca-certificates curl gnupg
...
Setting up ca-certificates (20240203) ...
Setting up curl (7.81.0-1ubuntu1.20) ...
Setting up gnupg (2.2.27-3ubuntu2.1) ...
If they are already installed, apt reports 0 upgraded, 0 newly installed.
sudo install -m 0755 -d /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/ubuntu/gpg \
| sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
sudo chmod a+r /etc/apt/keyrings/docker.gpg
Expected output: these commands print nothing on success (curl is silent with -s). Errors usually mean no network or a bad path under /etc/apt/keyrings.
Add the Docker apt source and refresh the index:
echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu $(. /etc/os-release && echo "$VERSION_CODENAME") stable" \
| sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
sudo apt update
Expected output from apt update should include a line from Docker’s host, for example:
Hit:1 https://download.docker.com/linux/ubuntu jammy InRelease
Hit:2 http://archive.ubuntu.com/ubuntu jammy InRelease
Reading package lists... Done
Your Ubuntu codename (focal, jammy, noble, …) replaces jammy above.
apt-cache policy docker-ce
Expected output (version numbers change over time):
docker-ce:
Installed: (none)
Candidate: 5:27.5.1-1~ubuntu.22.04~jammy
Version table:
5:27.5.1-1~ubuntu.22.04~jammy 500
500 https://download.docker.com/linux/ubuntu jammy/stable amd64 Packages
Installed: (none) is correct before the first install. The Candidate must list https://download.docker.com/linux/ubuntu — not only Ubuntu’s universe mirror.
sudo apt install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin
Expected output (abbreviated):
Reading package lists... Done
The following NEW packages will be installed:
containerd.io docker-buildx-plugin docker-ce docker-ce-cli docker-compose-plugin
...
Setting up containerd.io (1.7.25-1) ...
Setting up docker-ce-cli (5:27.5.1-1~ubuntu.22.04~jammy) ...
Setting up docker-ce (5:27.5.1-1~ubuntu.22.04~jammy) ...
Created symlink /etc/systemd/system/multi-user.target.wants/docker.service → /lib/systemd/system/docker.service.
Confirm with:
sudo systemctl status docker
Expected output (press q to quit the pager):
● docker.service - Docker Application Container Engine
Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled)
Active: active (running) since Fri 2026-08-21 10:15:03 UTC; 12s ago
TriggeredBy: ● docker.socket
Docs: https://docs.docker.com
Main PID: 2148 (dockerd)
Tasks: 8
Memory: 42.1M
CPU: 312ms
CGroup: /system.slice/docker.service
└─2148 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock
Look for Active: active (running). If the service is stopped:
sudo systemctl start docker
Expected output: no message on success. Re-run status to confirm.
Optional version check:
docker --version
Expected output:
Docker version 27.5.1, build 9fceb4c
sudo docker run hello-world
Expected output:
Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world
c1ec31eb5944: Pull complete
Digest: sha256:…
Status: Downloaded newer image for hello-world:latest
Hello from Docker!
This message shows that your installation appears to be working correctly.
To generate this message, Docker took the following steps:
1. The Docker client contacted the Docker daemon.
2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
3. The Docker daemon created a new container from that image…
4. The Docker daemon streamed that output to the Docker client…
To try something more ambitious, you can run an Ubuntu container…
That confirms client ↔ daemon ↔ Docker Hub connectivity.
Without the docker group, a plain docker call fails:
docker run hello-world
Expected output (before group membership):
permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: …
Add your user:
sudo usermod -aG docker "$USER"
Expected output: no message on success.
Apply the group (new login shell or newgrp):
newgrp docker
groups
Expected output from groups (order varies):
youruser sudo docker
Then:
docker run --rm hello-world
Expected output: the same “Hello from Docker!” block as Step 5, without sudo. Membership in docker is effectively root-equivalent — treat it like privileged access. Deep dive: Run Docker Without sudo on Ubuntu.
Pull an Ubuntu image:
docker pull ubuntu
Expected output:
Using default tag: latest
latest: Pulling from library/ubuntu
…: Pull complete
Digest: sha256:…
Status: Downloaded newer image for ubuntu:latest
docker.io/library/ubuntu:latest
List local images:
docker images
Expected output:
REPOSITORY TAG IMAGE ID CREATED SIZE
ubuntu latest 1d622ef86b13 3 weeks ago 78.1MB
hello-world latest 74cc54a32868 4 months ago 13.3kB
Interactive shell (exits when you type exit):
docker run -it --rm ubuntu bash
Expected output: prompt changes to something like root@a1b2c3d4e5f6:/#. Type exit to leave; --rm deletes the container.
List all containers:
docker ps -a
Expected output (IDs and names differ):
CONTAINER ID IMAGE COMMAND CREATED STATUS NAMES
587000e49d53 hello-world "/hello" 5 minutes ago Exited (0) 5 minutes ago adoring_kowalevski
Remove a stopped container:
docker rm adoring_kowalevski
Expected output:
adoring_kowalevski
More patterns: Working with Docker Images and Containers.
Ubuntu 20.04 (Focal), 22.04 (Jammy), and 24.04 (Noble). The VERSION_CODENAME substitution picks the matching Docker suite automatically.
docker.io from Ubuntu’s default repos?Prefer docker-ce from Docker’s official repository so you get current Engine, Buildx, and the Compose plugin. docker.io often lags.
sudo apt purge docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin
sudo rm -rf /var/lib/docker /var/lib/containerd
Removing /var/lib/docker deletes images, containers, and volumes permanently.
You installed Docker CE from Docker’s official Ubuntu repository, verified systemctl shows the daemon running, and confirmed the install with hello-world. Keep packages updated with sudo apt update && sudo apt upgrade, and prefer Compose or Dockerfiles over long-lived interactive containers for anything you intend to ship.