Berikut ini tutorial untuk melakukan installasi Docker pada Linux Ubuntu 18.04 / 18.10
Step 1 - Update Package

sudo apt-get update

Step 2 - Install package agar apt dapat menambahkan Repo menggunakan HTTPS

sudo apt-get install \
    apt-transport-https \
    ca-certificates \
    curl \
    software-properties-common

Step 3 - Tambahkan Docker GPG Official Key

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

Step 4 - Verifikasi apakah key sesuai seperti dibawah ini

sudo apt-key fingerprint 0EBFCD88

pub   4096R/0EBFCD88 2017-02-22
      Key fingerprint = 9DC8 5822 9FC7 DD38 854A  E2D8 8D81 803C 0EBF CD88
uid                  Docker Release (CE deb) <docker@docker.com>
sub   4096R/F273FCD8 2017-02-22

Step 5 - Menambahkan docker repository

sudo add-apt-repository \
   "deb [arch=amd64] https://download.docker.com/linux/ubuntu \
   $(lsb_release -cs) \
   stable"

Step 6 - Update Package

sudo apt-get update

Step 7 - Install Docker

sudo apt-get install docker-ce

Step 8 - Memastikan Docker Terinstall

sudo docker run hello-world

Jika hasilnya seperti dibawah maka docker sudah berhasil terinstall dengan baik.

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.
    (amd64)
 3. The Docker daemon created a new container from that image which runs the
    executable that produces the output you are currently reading.
 4. The Docker daemon streamed that output to the Docker client, which sent it
    to your terminal.

To try something more ambitious, you can run an Ubuntu container with:
 $ docker run -it ubuntu bash

Share images, automate workflows, and more with a free Docker ID:
 https://hub.docker.com/

For more examples and ideas, visit:
 https://docs.docker.com/get-started/

Sekian tutorial install docker di linux ubuntu dari saya. Terima kasih.