How to Uninstall Docker in Ubuntu

To Uninstall Docker completely from Ubuntu machine

Method 1: 

To completely uninstall Docker:

Step 1

dpkg -l | grep -i docker

To identify what installed the package you have:

Step 2

sudo apt-get purge -y docker-engine docker docker.io docker-ce  

sudo apt-get autoremove -y --purge docker-engine docker docker.io docker-ce  

The above commands will not remove images, containers, volumes, or user-created configuration files on your host. If you wish to delete all images, containers, and volumes run the following commands:

sudo rm -rf /var/lib/docker /etc/docker
sudo rm /etc/apparmor.d/docker
sudo groupdel docker
sudo rm -rf /var/run/docker.sock

You have removed Docker from the system completely.

Method 2: 

 I find it much easier to uninstall docker if it is installed with snap. You simply do: (Source: Stackover flow)

sudo snap remove docker

and to delete all related files,

sudo find / -name "*docker*" -exec `rm -rf` {} +
Method 3: 
sudo apt-get purge -y docker.io docker-ce

sudo apt-get autoremove -y --purge docker.io docker-ce

sudo apt-get autoclean

sudo rm -rf /var/lib/docker

sudo rm -rf /etc/docker

sudo rm /etc/apparmor.d/docker

sudo apt-get purge runc containerd docker.io docker-ce

 this command to see if docker files are any where else:
sudo find / -name '*docker*'