Necesitaba usar docker en mi sistema Ubuntu 18.04 LTS Bionic Beaver, así que manos a la obra.

Entramos a la terminal y tecleamos lo siguiente:

cd ~
sudo apt update
sudo apt install apt-transport-https ca-certificates curl software-properties-common
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu bionic stable"
sudo apt update
sudo apt install docker-ce
sudo apt clean && sudo apt autoclean
sudo systemctl status docker
sudo usermod -aG docker ${USER}
su - ${USER}
sudo usermod -aG docker proyectosbeta
docker info

Sale por pantalla:

Containers: 0
Running: 0
Paused: 0
Stopped: 0
Images: 0
Server Version: 18.09.1
Storage Driver: overlay2
Backing Filesystem: extfs
Supports d_type: true
Native Overlay Diff: true
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins:
Volume: local
Network: bridge host macvlan null overlay
Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
Swarm: inactive
Runtimes: runc
Default Runtime: runc
Init Binary: docker-init
containerd version: 9754871865f7fe2f4e74d43e2fc7ccd237edcbce
runc version: 96ec2177ae841256168fcf76954f7177af9446eb
init version: fec3683
Security Options:
apparmor
seccomp
Profile: default
Kernel Version: 4.15.0-45-generic
Operating System: Ubuntu 18.04.1 LTS
OSType: linux
Architecture: x86_64
CPUs: 8
Total Memory: 15.55GiB
Name: estrellaFugaz
ID: Y7RU:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX
Docker Root Dir: /var/lib/docker
Debug Mode (client): false
Debug Mode (server): false
Registry: https://index.docker.io/v1/
Labels:
Experimental: false
Insecure Registries:
127.0.0.0/8
Live Restore Enabled: false
Product License: Community Engine
WARNING: No swap limit support

Ya pueden instalar todos los contenedores que quieran!!!

Fuente: Digital Ocean