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⇱ How To Install and Use Docker on Ubuntu | DigitalOcean


How To Install and Use Docker on Ubuntu

Updated on January 21, 2026

By Anish Singh Walia

Sr Technical Content Strategist and Team Lead

English
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👁 How To Install and Use Docker on Ubuntu

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About the author

👁 Anish Singh Walia
Anish Singh Walia
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Sr Technical Content Strategist and Team Lead
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I help Businesses scale with AI x SEO x (authentic) Content that revives traffic and keeps leads flowing | 3,000,000+ Average monthly readers on Medium | Sr Technical Writer(Team Lead) @ DigitalOcean | Ex-Cloud Consultant @ AMEX | Ex-Site Reliability Engineer(DevOps)@Nutanix

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I have installed Ubuntu 20.04 server and am struggling to install Docker. I am getting stuck on the step to add the GPG key for the official Docker repository; when I run this command:

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -

I get this response:

curl: (7) Failed to connect to download.docker.com port 443: No route to host
gpg: no valid OpenPGP data found.

I can’t work out how to move forward, so any ideas would be appreciated, thanks in advance.

I have a brand new droplet and there appears to be something wrong with the “stable” release using these instructions. When I run sudo systemctl status docker I get a bunch of error and it throws me into Vi:

● docker.service - Docker Application Container Engine
 Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled)
 Active: active (running) since Tue 2020-06-23 20:47:38 AEST; 15s ago
TriggeredBy: ● docker.socket
 Docs: https://docs.docker.com
 Main PID: 20339 (dockerd)
 Tasks: 8
 Memory: 34.7M
 CGroup: /system.slice/docker.service
 └─20339 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock

Jun 23 20:47:38 projects dockerd[20339]: time="2020-06-23T20:47:38.156277373+10:00" level=warning msg="Your kernel does not support cgroup rt runtime"
Jun 23 20:47:38 projects dockerd[20339]: time="2020-06-23T20:47:38.156436943+10:00" level=warning msg="Your kernel does not support cgroup blkio weigh>
Jun 23 20:47:38 projects dockerd[20339]: time="2020-06-23T20:47:38.156588335+10:00" level=warning msg="Your kernel does not support cgroup blkio weigh>
Jun 23 20:47:38 projects dockerd[20339]: time="2020-06-23T20:47:38.156960819+10:00" level=info msg="Loading containers: start."
Jun 23 20:47:38 projects dockerd[20339]: time="2020-06-23T20:47:38.420014263+10:00" level=info msg="Default bridge (docker0) is assigned with an IP ad>
Jun 23 20:47:38 projects dockerd[20339]: time="2020-06-23T20:47:38.643617453+10:00" level=info msg="Loading containers: done."
Jun 23 20:47:38 projects dockerd[20339]: time="2020-06-23T20:47:38.729797979+10:00" level=info msg="Docker daemon" commit=48a66213fe graphdriver(s)=ov>
Jun 23 20:47:38 projects dockerd[20339]: time="2020-06-23T20:47:38.730768864+10:00" level=info msg="Daemon has completed initialization"
Jun 23 20:47:38 projects systemd[1]: Started Docker Application Container Engine.
Jun 23 20:47:38 projects dockerd[20339]: time="2020-06-23T20:47:38.776191749+10:00" level=info msg="API listen on /run/docker.sock"

Although the last message claims Docker has started, I can’t run any containers. Any suggestions would be great.

Thx… Nice Demo… worked right out of the box… easy to follow…

sudo add-apt-repository “deb [arch=amd64] https://download.docker.com/linux/ubuntu focal stable”

When I run the above command on an Ubuntu 20.4 instance on AWS, then i get the following response

"E: The repository ‘https://download.docker.com/linux/ubuntu/gpg focal Release’ does not have a Release file. N: Updating from such a repository can’t be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. " I am trying this on January 2021, about 6 months after the article. Yet the Release file is not available.

How should we proceed

Thx very helpful tutorial. However I got error during apt-key command

Warning: apt-key is deprecated.

I have installed ubuntu 20.04 from ubuntu official website and Docker desktop from Docker offical website. When I try checking the status of docker using the command - sudo systemctl status docker It fails with the message - System has not been booted with systemd as init system (PID 1). Can’t operate. Failed to connect to bus: Host is down I would request Brian Hogan(original poster of this page) to help solve this issue first as rest of the process does not hold any meaning for me. This issue of systemctl and systemd not available with WSL2 is a general issue and needs to be fixed first before venturing into installing docker through ubuntu 20.04 Thanks.

Anyone knows why this error?

E: gnupg, gnupg2 and gnupg1 do not seem to be installed, but one of them is required for this operation
 % Total % Received % Xferd Average Speed Time Time Time Current
 Dload Upload Total Spent Left Speed
100 983 100 983 0 0 8776 0 --:--:-- --:--:-- --:--:-- 8776
(23) Failed writing body

Thanks for sharing, worked great.

This comment has been deleted

After running the Command:

docker run hello-world

I Get this massage:

docker: error pulling image configuration: download failed after attempts=6: net/http: TLS handshake timeout.

“Ubuntu 20.04.4 LTS”

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