nvidia-docker : Got permission denied - linux

Question

Docker newbie question here, so please be nice.
I know this might be asked before but I could not find anything related to nvidia-docker.
I completed the installation instructions on the official guide.
When I wanted to test Nvidia-docker:
docker run --gpus all nvidia/cuda:10.0-base nvidia-smi
I got this error:
(base) user#adminme:~$ docker run --gpus all --rm nvidia/cuda nvidia-smi
docker: Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Post http://%2Fvar%2Frun%2Fdocker.sock/v1.40/containers/create: dial unix /var/run/docker.sock: connect: permission denied.
See 'docker run --help'.
I found this answer here, but it felt a bit different for my case. I am very new to docker and still learning. let me know what you think?
here is some information about my remote Linux machine:
(base) user#adminme:~$ lspci | grep -i nvidia
02:00.0 VGA compatible controller: NVIDIA Corporation GP104 [GeForce GTX 1080] (rev a1)
02:00.1 Audio device: NVIDIA Corporation GP104 High Definition Audio Controller (rev a1)
nvidia-smi command:
(base) user#adminme:~$ nvidia-smi
Sun May 31 01:12:25 2020
+-----------------------------------------------------------------------------+
| NVIDIA-SMI 440.64.00 Driver Version: 440.64.00 CUDA Version: 10.2 |
|-------------------------------+----------------------+----------------------+
| GPU Name Persistence-M| Bus-Id Disp.A | Volatile Uncorr. ECC |
| Fan Temp Perf Pwr:Usage/Cap| Memory-Usage | GPU-Util Compute M. |
|===============================+======================+======================|
| 0 GeForce GTX 1080 Off | 00000000:02:00.0 Off | N/A |
| 0% 33C P8 9W / 215W | 17MiB / 8116MiB | 0% Default |
+-------------------------------+----------------------+----------------------+
+-----------------------------------------------------------------------------+
| Processes: GPU Memory |
| GPU PID Type Process name Usage |
|=============================================================================|
| 0 2545 G /usr/lib/xorg/Xorg 15MiB |
+-----------------------------------------------------------------------------+
docker-version :
(base) user#adminme:~$ docker --version
Docker version 19.03.10, build 9424aeaee9

Answer 1

The quick fix would be to run the container using sudo:
sudo docker run --gpus all nvidia/cuda:10.0-base nvidia-smi
If you want to run docker as non-root user then you need to add it to the docker group.
Create the docker group if it does not exist
sudo groupadd docker
Add your user to the docker group.
sudo usermod -aG docker $USER
Run the following command or Logout and login again and run (that doesn't work you may need to reboot your machine first)
newgrp docker
Check if docker can be run without root
docker run --gpus all nvidia/cuda:10.0-base nvidia-smi
Ref:- https://docs.docker.com/engine/install/linux-postinstall/

Answer 2

In addition to what nischay goyal answered, sometimes after adding the user to the docker group you have to do
su - ${USER}
in order to log out and log back.