Add documentation.

Author: rohitagarwal003

docs/README.md

@@ -12,6 +12,8 @@
 
 * **Caching Images** ([cache.md](cache.md)): Caching non-minikube images in minikube
 
+* **GPUs** ([gpu.md](gpu.md)): Using NVIDIA GPUs on minikube
+
 ### Installation and debugging
 
 * **Driver installation** ([drivers.md](drivers.md)): In depth instructions for installing the various hypervisor drivers

docs/gpu.md

@@ -0,0 +1,116 @@
+# (Experimental) NVIDIA GPU support in minikube
+
+minikube has experimental support for using NVIDIA GPUs on Linux.
+
+## Using NVIDIA GPUs on minikube on Linux with `--vm-driver=kvm2`
+
+When using NVIDIA GPUs with the kvm2 vm-driver. We passthrough spare GPUs on the
+host to the minikube VM. Doing so has a few prerequisites:
+
+- You must install the [kvm2 driver](drivers.md#kvm2-driver). If you already had
+  this installed make sure that you fetch the latest
+  `docker-machine-driver-kvm2` binary that has GPU support.
+
+- Your CPU must support IOMMU. Different vendors have different names for this
+  technology. Intel calls it Intel VT-d. AMD calls it AMD-Vi. Your motherboard
+  must also support IOMMU.
+
+- You must enable IOMMU in the kernel: add `intel_iommu=on` or `amd_iommu=on`
+  (depending to your CPU vendor) to the kernel command line. Also add `iommu=pt`
+  to the kernel command line.
+
+- You must have spare GPUs that are not used on the host and can be passthrough
+  to the VM. These GPUs must not be controlled by the nvidia/nouveau driver. You
+  can ensure this by either not loading the nvidia/nouveau driver on the host at
+  all or assigning the spare GPU devices to stub kernel modules like `vfio-pci`
+  or `pci-stub` at boot time. You can do that by adding the
+  [vendorId:deviceId](https://pci-ids.ucw.cz/read/PC/10de) of your spare GPU to
+  the kernel command line. For ex. for Quadro M4000 add `pci-stub.ids=10de:13f1`
+  to the kernel command line. Note that you will have to do this for all GPUs
+  you want to passthrough to the VM and all other devices that are in the IOMMU
+  group of these GPUs.
+
+- Once you reboot the system after doing the above, you should be ready to you
+  GPUs with kvm2. Run the following command to start minikube:
+  ```
+  minikube start --vm-driver kvm2 --gpu
+  ```
+  This command will check if all the above conditions are satisfied and
+  passthrough spare GPUs found on the host to the VM.
+
+  If this succeeded, run the following commands:
+  ```
+  minikube addons enable nvidia-gpu-device-plugin
+  minikube addons enable nvidia-driver-installer
+  ```
+  This will install the NVIDIA driver (that works for GeForce/Quadro cards)
+  on the VM.
+
+- If everything succeeded, you should be able to see `nvidia.com/gpu` in the
+  capacity:
+  ```
+  kubectl get nodes -ojson | jq .items[].status.capacity
+  ```
+
+### Where can I learn more about GPU passthrough?
+See the excellent documentation at
+https://wiki.archlinux.org/index.php/PCI_passthrough_via_OVMF
+
+### Why are so many manual steps required to use GPUs with kvm2 on minikube?
+These steps require elevated privileges which minikube doesn't run with and they
+are disruptive to the host, so we decided to not do them automatically.
+
+
+## Using NVIDIA GPU on minikube on Linux with `--vm-driver=none`
+
+NOTE: This approach used to expose GPUs here is different than the approach used
+to expose GPUs with `--vm-driver=kvm2`. Please don't mix these instructions.
+
+- Install minikube.
+
+- Install the nvidia driver, nvidia-docker and configure docker with nvidia as
+  the default runtime. See instructions at
+  https://github.com/NVIDIA/nvidia-docker
+
+- Start minikube:
+  ```
+  minikube start --vm-driver=none --apiserver-ips 127.0.0.1 --apiserver-name localhost
+  ```
+
+- Install NVIDIA's device plugin:
+  ```
+  kubectl create -f https://raw.githubusercontent.com/NVIDIA/k8s-device-plugin/v1.10/nvidia-device-plugin.yml
+  ```
+
+
+## Why does minikube not support NVIDIA GPUs on macOS?
+VM drivers supported by minikube for macOS doesn't support GPU passthrough:
+- [mist64/xhyve#108](https://github.com/mist64/xhyve/issues/108)
+- [moby/hyperkit#159](https://github.com/moby/hyperkit/issues/159)
+- [VirtualBox docs](http://www.virtualbox.org/manual/ch09.html#pcipassthrough)
+
+Also:
+- For quite a while, all Mac hardware (both laptops and desktops) have come with
+  Intel or AMD GPUs (and not with NVIDIA GPUs). Recently, Apple added [support
+  for eGPUs](https://support.apple.com/en-us/HT208544), but even then all the
+  supported GPUs listed are AMD’s.
+
+- nvidia-docker [doesn't support
+  macOS](https://github.com/NVIDIA/nvidia-docker/issues/101) either.
+
+
+## Why does minikube not support NVIDIA GPUs on Windows?
+minikube suppports Windows host through Hyper-V or VirtualBox.
+
+- VirtualBox doesn't support PCI passthrough for [Windows
+  host](http://www.virtualbox.org/manual/ch09.html#pcipassthrough).
+
+- Hyper-V supports DDA (discrete device assignment) but [only for Windows Server
+  2016](https://docs.microsoft.com/en-us/windows-server/virtualization/hyper-v/plan/plan-for-deploying-devices-using-discrete-device-assignment)
+
+Since the only possibility of supporting GPUs on minikube on Windows is on a
+server OS where users don't usually run minikube, we haven't invested time in
+trying to support NVIDIA GPUs on minikube on Windows.
+
+Also, nvidia-docker [doesn't support
+Windows](https://github.com/NVIDIA/nvidia-docker/issues/197) either.