Install on Ubuntu-22.04
Much of this page shamelessly stolen from This Digital Ocean Post.
Docker
is an application that simplifies the process of managing application processes in containers. Containers
let you run your applications in resource-isolated processes. They’re similar to virtual machines, but containers are more portable, more resource-friendly, and more dependent on the host operating system.
For a detailed introduction to the different components of a Docker container, ask me.
In this tutorial, you’ll install and use Docker Community Edition (CE) on Ubuntu 22.04. You’ll install Docker itself, work with containers and images, and push an image to a Docker Repository.
To follow this tutorial, you will need the following:
One Ubuntu 22.04 server set up by following the Ubuntu 22.04 initial server setup guide, including a sudo non-root user and a firewall. An account on Docker Hub if you wish to create your own images and push them to Docker Hub, as shown in Steps 7 and 8.
Set up apt proxy config
Add skwirreltrap to /etc/hosts
|
|
add our ssl certs
|
|
The Docker installation package available in the official Ubuntu repository may not be the latest version. To ensure we get the latest version, we’ll install Docker from the official Docker repository. To do that, we’ll add a new package source, add the GPG key from Docker to ensure the downloads are valid, and then install the package.
First, update your existing list of packages:
|
|
Next, install a few prerequisite packages which let apt use packages over HTTPS:
|
|
Then add the GPG key for the official Docker repository to your system:
|
|
Add the Docker repository to APT sources:
|
|
Update your existing list of packages again for the addition to be recognized:
|
|
Make sure you are about to install from the Docker repo instead of the default Ubuntu repo:
|
|
You’ll see output like this, although the version number for Docker may be different:
Output of apt-cache policy docker-ce
|
|
Notice that docker-ce
is not installed, but the candidate for installation is from the Docker repository for Ubuntu 22.04 (jammy).
Finally, install Docker:
sudo apt install docker-ce
To be explicit, however:
|
|
Docker should now be installed, the daemon started, and the process enabled to start on boot.
Check that it’s running:
sudo systemctl status docker
The output should be similar to the following, showing that the service is active and running:
Output
|
|
Installing Docker now gives you not just the Docker service (daemon) but also the docker command line utility, or the Docker client.
We’ll explore how to use the docker command later in this tutorial.
Docker’s config can be managed a few different ways… but on hosts configureed to use systemd, the proxy config cannot be managed in the daemon options in /etc/default/docker
lvcreate TinkyVG -n TinkyDataLV -L +50G mkfs.ext4 -m 0 -L TinkyDataFS -M /data /dev/mapper/TinkyVG-TinkyDataLV echo ‘LABEL=TinkyDataFS /data ext4 defaults 0 0’ » /etc/fstab root@tinky:~# mount -=a^C root@tinky:~# mkdir /data root@tinky:~# mount -a root@tinky:~# ls /data lost+found mkdir /data/docker mkdir /data/docker-tmp service docker stop&& cd /var/lib/docker/&& tar cpf - . | (cd /data/docker/&& tar xpf -); du -sh /data/docker /var/lib/docker&& cd / && rm -rf /var/lib/docker; ln -s /data/docker /var/lib/docke
/etc/docker/daemon.json
|
|
By default, the docker command can only be run the root user or by a user in the docker group, which is automatically created during Docker’s installation process. If you attempt to run the docker command without prefixing it with sudo or without being in the docker group, you’ll get an output like this:
Output
docker: Cannot connect to the Docker daemon. Is the docker daemon running on this host?.
See ‘docker run --help
’.
If you want to avoid typing sudo whenever you run the docker command, add your username to the docker group:
sudo usermod -aG docker ${USER}
Copy
To apply the new group membership, log out of the server and back in, or type the following:
su - ${USER}
You will be prompted to enter your user’s password to continue.
Confirm that your user is now added to the docker group by typing:
groups
sammy sudo docker
If you need to add a user to the docker group that you’re not logged in as, declare that username explicitly using:
sudo usermod -aG docker username Copy The rest of this article assumes you are running the docker command as a user in the docker group. If you choose not to, please prepend the commands with sudo.
Let’s explore the docker command next.
Step 3 — Using the Docker Command