title: Add nvidia runtime to docker runtimes
body: <p>I’m running a virtual vachine on <code>GCP</code> with a tesla GPU. 
  And try to deploy a <code>PyTorch</code>-based app to accelerate it with GPU.</p>
  
  <p><strong>I want to make docker use this GPU, have access to it from containers.</strong></p>
  
  <p>I managed to install all drivers on host machine, and the app runs fine there, but when I try to run it in docker (based on nvidia/cuda container) pytorch fails:</p>
  
  <pre><code>File "/usr/local/lib/python3.6/dist-packages/torch/cuda/__init__.py", line 82, 
  in _check_driver http://www.nvidia.com/Download/index.aspx""")
  AssertionError: 
  Found no NVIDIA driver on your system. Please check that you have an NVIDIA GPU and installed a driver from
  </code></pre>
  
  <p>To get some info about nvidia drivers visible to the container, I run this:  </p>
  
  <p><code>docker run --runtime=nvidia --rm nvidia/cuda nvidia-smi</code><br>
  But it complains: <code>docker: Error response from daemon: Unknown runtime specified nvidia.</code></p>
  
  <p>On the host machine <code>nvidia-smi</code> output looks like this:</p>
  
  <pre><code>+-----------------------------------------------------------------------------+
  | NVIDIA-SMI 440.33.01    Driver Version: 440.33.01    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  Tesla P100-PCIE...  On   | 00000000:00:04.0 Off |                    0 |
  | N/A   39C    P0    35W / 250W |    873MiB / 16280MiB |      0%      Default |
  +-------------------------------+----------------------+----------------------+
  </code></pre>
  
  <p>If I check my runtimes in docker, I get only <code>runc</code> runtime, no <code>nvidia</code> as in examples around the internet.</p>
  
  <pre><code>$ docker info|grep -i runtime
   Runtimes: runc
   Default Runtime: runc
  </code></pre>
  
  <p><strong>How can I add this <code>nvidia</code> runtime environment to my docker?</strong></p>
  
  <p>Most posts and questions I found so far say something like "I just forgot to restart my docker daemon, it worked", but it does not help me. Whot should I do?</p>
  
  <p>I checked many issues on github, and <a href="https://stackoverflow.com/questions/57957491/nvidia-docker-unknown-runtime-specified-nvidia">#1</a>, <a href="https://stackoverflow.com/questions/52865988/nvidia-docker-unknown-runtime-specified-nvidia">#2</a> and <a href="https://stackoverflow.com/questions/50364031/cant-execute-nvidia-runtime-on-docker">#3</a> StackOverflow questions - didn't help.</p>