Verify that you have LATEST nvidia driver installed.

Install Docker:
sudo apt-get update
sudo apt-get upgrade
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 systemctl status docker
sudo usermod -aG docker ${USER}

Deepstream Docker:
sudo apt update
distribution=$(. /etc/os-release;echo $ID$VERSION_ID)

curl -s -L https://nvidia.github.io/nvidia-docker/gpgkey | sudo apt-key add -

curl -s -L https://nvidia.github.io/nvidia-docker/$distribution/nvidia-docker.list | sudo tee /etc/apt/sources.list.d/nvidia-docker.list 
sudo apt-get update

sudo apt-get install -y nvidia-docker2
sudo systemctl restart docker
docker pull nvcr.io/nvidia/deepstream:5.0.1-20.09-triton

docker images

xhost +
docker run --gpus all -it --rm -v /home/YOUR USER NAME/deep-workspace:/deep-workspace/ -v /tmp/.X11-unix:/tmp/.X11-unix -e DISPLAY=$DISPLAY --security-opt seccomp=unconfined  -w /opt/nvidia/deepstream/deepstream-5.0  (f5ed161342f4) <- REPLACE WITH THE ACTUAL DEEPSTREAM ID THAT WE GOT FROM THE DOCKER IMAGES LIST

-->From here, we are in the docker:

Updates packages (apt-get update/upgrade)
\!/ YOU ARE ALREADY IN ROOT MODE, SO NO NEED TO SUDO (otherwise you get sudo not found error)
Install software you want (like python..etc) and if you want a graphical IDE, you can install nvidia Nsight:
sudo apt-get install -y nvidia-nsight
when done, you need to save the docker (because when you quit a docker, it resets).
First, open a new terminal from the host machine and do:
docker ps

this will give you current docker session ID, 
Then do: docker commit <container id> <new docker name>

once done, you can exit the container by doing exit

To use the new updated container, just do docker images, then do the docker run --gpus all ..Etc command by replacing the last Docker Image id by the new renamed one's.

Later on, everytime you finish working, just commit using the same name and it should be good to go.