For those of you who didn’t know, Docker is an open-source tool that makes creating and managing Linux containers (LXC) easy. With Docker, the applications resides inside the container on top of the Linux operating system. Docker uses Kernel features such as cgroups and namespace to allow independent container to run on single os instance.
This article assumes you have at least basic knowledge of linux, know how to use the shell, and most importantly, you host your site on your own VPS. The installation is quite simple. I will show you through the step by step installation Docker on Ubuntu 14.04.
Step 1. First of all make sure that all packages are up to date.
Step 2. Install Docker using the apt-get command.
apt-get install docker.io
Start and enable Docker service:
service docker.io status
service docker.io start
Create a symlink to the Docker executable so that the Docker documentation commands can be executed without changing the path. This is required because the Ubuntu package for Docker is installed to a different directory to the default Docker recommendation:
ln -sf /usr/bin/docker.io /usr/local/bin/docker
sed -i '$acomplete -F _docker docker' /etc/bash_completion.d/docker.io
Step 3. Download Docker Container.
Let’s begin using Docker, Download the ubuntu Docker image:
docker pull ubuntu
Step 4. Run a Docker Container.
As we can see ubuntu container has been started and we got the bash shell. In docker command we have used options like ‘-i attaches stdin and stdout’ and ‘-t allocates a terminal or console’. Once you exit the shell, the Docker image will be switched off.
docker run -i -t ubuntu /bin/bash
Alternatively, you may want to launch a specific version of Ubuntu: a container can contain multiple images. This command shows the available images that you have downloaded so far:
sudo docker.io images
REPOSITORY TAG IMAGE ID
ubuntu vivid 76ca2fd90787
ubuntu 15.04 76ca2fd90787
ubuntu utopic cfaba6b5fefe
ubuntu 14.10 cfaba6b5fefe
ubuntu 14.04 5ba9dab47459
ubuntu trusty 5ba9dab47459
ubuntu 14.04.1 5ba9dab47459
ubuntu latest 5ba9dab47459
ubuntu 12.04.5 69c02692b0c1
Now if you want to launch another version, you can simply preprend the TAG of the version you want to launch to the container in this way:
sudo docker.io run -i -t ubuntu:14.10 /bin/bash
Congratulation’s! You have successfully installed Docker. Thanks for using this tutorial for installing Docker on Ubuntu 14.04 system.