Run uname -a to check the version of the currently running Linux kernel:

uname -a

Check that it's a 64Bit Kernel (x86_64). Docker won't work without this.

Check the Ubuntu version.

cat /etc/lsb-release

The command shows that the Ubuntu version is 16.04.

It is recommended to update Ubuntu before you install new software. Run the following command to fetch the latest updates from the Ubuntu repository and install them.

apt-get update apt-get upgrade

Now install docker with the apt command:

apt-get install -y docker.io

Wait until the installation has been completed, then you can start Docker with the systemctl command:

systemctl start docker

Enable docker to run at system boot:

systemctl enable docker

You might also want to check the docker version:

docker version

Show the currently installed Docker version.

Now docker is installed in your system. You can start making a container by downloading a Docker Image from the Docker Registry.