intel-device-plugins-for-kubernetes/cmd/fpga_plugin

Intel FPGA device plugin for Kubernetes

Table of Contents

• Introduction
• Component overview
• FPGA modes
• Installation
  • Pre-built images
  • Dependencies
  • Getting the source code
  • Verify node kubelet config
  • Deploying as a DaemonSet
    • Create a service account
    • Deploying region mode
    • Deploying af mode
    • Deploy the DaemonSet
    • Verify plugin registration
    • Building the plugin image
  • Deploy by hand
    • Build FPGA device plugin
    • Run FPGA device plugin in af mode
    • Run FPGA device plugin in region mode
• Next steps

Introduction

This FPGA device plugin is part of a collection of Kubernetes components found within this repository that enable integration of Intel FPGA hardware into Kubernetes.

The following hardware platforms are supported:

• Intel Arria 10
• Intel Stratix 10

The components support the Open Programmable Acceleration Engine (OPAE) interface.

The components together implement the following features:

• discovery of pre-programmed accelerator functions
• discovery of programmable regions
• orchestration of FPGA programming
• access control for FPGA hardware

Component overview

The following components are part of this repository, and work together to support Intel FPGAs under Kubernetes:

• FPGA device plugin (this component)

  A Kubernetes device plugin that discovers available FPGA resources on a node and advertises them to the Kubernetes control plane via the node kubelet.

• FPGA admission controller webhook

  A Kubernetes admission controller webhook which can be used to dynamically convert logical resource names in pod specifications into actual FPGA resource names, as advertised by the device plugin.

  The webhook can also set environment variables to instruct the CRI-O prestart hook to program the FPGA before launching the container.

• FPGA CRI-O prestart hook

  A CRI-O prestart hook that, upon instruction from the FPGA admission controller, allocates and programs the FPGA before the container is launched.

The repository also contains an FPGA helper tool that may be useful during development, initial deployment and debugging.

FPGA modes

The FPGA plugin set can run in one of two modes:

• region mode, where the plugins locate and advertise regions of the FPGA, and facilitate programing of those regions with the requested bistreams.
• af mode, where the FPGA bitstreams are already loaded onto the FPGA, and the plugins discover and advertises the existing Accelerator Functions (AF).

The example YAML deployments described in this document only currently support af mode. To utilise region mode, either modify the existing YAML appropriately, or deploy 'by hand'.

Overview diagrams of af and region modes are below:

region mode:

af mode:

Installation

The below sections cover how to obtain, build and install this component.

Components can generally be installed either using DaemonSets or running them 'by hand' on each node.

Pre-built images

Pre-built images of the components are available on the Docker hub. These images are automatically built and uploaded to the hub from the latest master branch of this repository.

Release tagged images of the components are also available on the Docker hub, tagged with their release version numbers (of the form x.y.z, matching the branch/tag release number in this repo).

The deployment YAML files supplied with these components in this repository use the images with the devel tag by default. If you do not build your own local images, then your Kubernetes cluster may pull down the devel images from the Docker hub by default.

To use the release tagged versions of the images, edit the YAML deployment files appropriately.

The following images are available on the Docker hub:

• The FPGA plugin
• The FPGA admisson webhook
• The FPGA CRI-O prestart hook (in the initcontainer image)

Dependencies

All components have the same basic dependencies as the generic plugin framework dependencies

To obtain a fully operational FPGA enabled cluster, you must install all three major components:

• FPGA device plugin (this component)
• FPGA admission controller webhook
• FPGA prestart CRI-O hook

The CRI-O hook is only required if region mode is being used, but is installed by default by the FPGA plugin DaemonSet YAML, and is benign in af mode.

If using the af mode, and therefore not using the CRI-O prestart hook, runtimes other than CRI-O can be used (that is, the CRI-O hook presently only works with the CRI-O runtime).

The FPGA device plugin requires a Linux Kernel FPGA driver to be installed and enabled to operate. The plugin supports the use of either of following two drivers, and auto detects which is present and thus to use:

• The Linux Kernel in-tree DFL driver
• The out of tree OPAE driver

Install this component (FPGA device plugin) first, and then follow the links and instructions to install the other components.

Getting the source code

To obtain the YAML files used for deployment, or to obtain the source tree if you intend to do a hand-deployment or build your own image, you will require access to the source code:

$ mkdir -p $(go env GOPATH)/src/github.com/intel
$ git clone https://github.com/intel/intel-device-plugins-for-kubernetes $(go env GOPATH)/src/github.com/intel/intel-device-plugins-for-kubernetes

Verify node kubelet config

Every node that will be running the FPGA plugin must have the kubelet device-plugins configured. For each node, check that the kubelet device plugin socket exists:

$ ls /var/lib/kubelet/device-plugins/kubelet.sock
/var/lib/kubelet/device-plugins/kubelet.sock

Deploying as a DaemonSet

You can deploy the plugin in either of the modes, using the DaemonSet YAML supplied. Details are in the following sections. Actions common to both deployment modes are detailed first. Mode specific actions are then detailed.

If you intend to deploy your own image, you will need to reference the image build section first.

If you do not want to deploy the devel tagged image, you will need to edit the YAML deployment files to reference your required image.

For beta testing: new deployment model

The FPGA plugin deployment is currently being rewritten to enable straight-forward deployment of both af and region modes. The deployment has two steps:

1. Run scripts/fpga-plugin-prepare-for-kustomization.sh. This will create the necessary secrets: a key and a signed certificate for the FPGA admission controller.

2. Depending on the FPGA mode, run either

   $ kubectl create -k deployments/fpga_plugin/overlays/af
   

   or

   $ kubectl create -k deployments/fpga_plugin/overlays/region
   

   This will create the service account and deploy both the FPGA plugin and the admission controller in the chosen mode.

This deployment model is under development. The remaining part of this document goes through the current deployment model: here for the FPGA plugin and in the next document for the FPGA admission controller.

Create a service account

To deploy the plugin in a production cluster, create a service account for the plugin:

$ kubectl create -f deployments/fpga_plugin/fpga_plugin_service_account.yaml
serviceaccount/intel-fpga-plugin-controller created
clusterrole.rbac.authorization.k8s.io/node-getter created
clusterrolebinding.rbac.authorization.k8s.io/get-nodes created

Deploying region mode

To deploy the FPGA plugin DaemonSet in region mode, you need to set the plugin mode annotation on all of your nodes, otherwise the FPGA plugin will run in its default af mode.

$ kubectl annotate node --all 'fpga.intel.com/device-plugin-mode=region'

Deploying af mode

To deploy the FPGA plugin DaemonSet in af mode, you do not need to set the mode annotation on your nodes, as the FPGA plugin runs in af mode by default.

Note: The FPGA plugin DaemonSet YAML also deploys the FPGA CRI-O hook initcontainer image, but it will be benign (un-used) when running the FPGA plugin in af mode.

Deploy the DaemonSet

You can then use the example DaemonSet YAML file provided to deploy the plugin.

$ kubectl create -f deployments/fpga_plugin/fpga_plugin.yaml
daemonset.apps/intel-fpga-plugin created

Verify plugin registration

Verify the FPGA plugin has been deployed on the nodes. The below shows the output you can expect in region mode, but similar output should be expected for af mode:

$ kubectl describe nodes | grep fpga.intel.com
fpga.intel.com/region-ce48969398f05f33946d560708be108a:  1
fpga.intel.com/region-ce48969398f05f33946d560708be108a:  1

Building the plugin image

If you need to build your own image from sources, and are not using the images available on the Docker Hub, follow the below details.

Note: The FPGA plugin DaemonSet YAML also deploys the FPGA CRI-O hook initcontainer image as well. You may also wish to build that image locally before deploying the FPGA plugin to avoid deploying the Docker hub default image.

The following will use docker to build a local container image called intel/intel-fpga-plugin with the tag devel. The image build tool can be changed from the default docker by setting the BUILDER argument to the Makefile.

$ make intel-fpga-plugin
...
Successfully tagged intel/intel-fpga-plugin:devel

This image launches fpga_plugin in af mode by default.

To use your own container image, modify the deployments/fpga_plugin/fpga_plugin.yaml file.

Deploy by hand

For development purposes, it is sometimes convenient to deploy the plugin 'by hand' on a node. In this case, you do not need to build the complete container image, and can build just the plugin.

Note: The FPGA plugin has a number of other associated items that may also need to be configured or installed. It is recommended you reference the actions of the DaemonSet YAML deployment for more details.

Build FPGA device plugin

When deploying by hand, you only need to build the plugin itself, and not the whole container image:

$ cd $(go env GOPATH)/src/github.com/intel/intel-device-plugins-for-kubernetes
$ make fpga_plugin

Run FPGA device plugin in af mode

$ export KUBE_CONF=/var/run/kubernetes/admin.kubeconfig # path to kubeconfig with admin's credentials
$ export NODE_NAME="<node name>" # if the node's name was overridden and differs from hostname
$ sudo -E $(go env GOPATH)/src/github.com/intel/intel-device-plugins-for-kubernetes/cmd/fpga_plugin/fpga_plugin -mode af -kubeconfig $KUBE_CONF
FPGA device plugin started in af mode
device-plugin start server at: /var/lib/kubelet/device-plugins/fpga.intel.com-af-f7df405cbd7acf7222f144b0b93acd18.sock
device-plugin registered

Note

: It is also possible to run the FPGA device plugin using a non-root user. To do this, the nodes' DAC rules must be configured to device plugin socket creation and kubelet registration. Furthermore, the deployments securityContext must be configured with appropriate runAsUser/runAsGroup.

Run FPGA device plugin in region mode

$ export KUBE_CONF=/var/run/kubernetes/admin.kubeconfig # path to kubeconfig with admin's credentials
$ export NODE_NAME="<node name>" # if the node's name was overridden and differs from hostname
$ sudo -E $(go env GOPATH)/src/github.com/intel/intel-device-plugins-for-kubernetes/cmd/fpga_plugin/fpga_plugin -mode region -kubeconfig $KUBE_CONF
FPGA device plugin started in region mode
device-plugin start server at: /var/lib/kubelet/device-plugins/fpga.intel.com-region-ce48969398f05f33946d560708be108a.sock
device-plugin registered

Next steps

Continue installation with the FPGA admission controller webhook.