Intel SGX admission controller for Kubernetes

Table of Contents

Introduction
Installation
- Pre-requisites
- Deployment

Introduction

The SGX admission controller is one of the components used to add support for Intel SGX functionality to Kubernetes.

NOTE: Installation of the SGX admission controller can be skipped if the SGX device plugin is operated with the Intel Device Plugins Operator since it integrates the controller’s functionality.

The SGX admission webhook is responsible for performing Pod mutations based on the sgx.intel.com/quote-provider pod annotation set by the user. The purpose of the webhook is to hide the details of setting the necessary device resources and volume mounts for using SGX remote attestation in the cluster. Furthermore, the SGX admission webhook is responsible for writing a pod/sandbox sgx.intel.com/epc annotation that is used by Kata Containers to dynamically adjust its virtualized SGX encrypted page cache (EPC) bank(s) size.

Installation

The following sections detail how to obtain, build and deploy the admission controller webhook plugin.

Pre-requisites

The default webhook deployment depends on having cert-manager installed. See its installation instructions here.

Note: The default deployment for the Intel SGX webhook uses self-signed certificates. For a production cluster, the certificate issuer should be properly set and not use a self-signed method.

Also if your cluster operates behind a corporate proxy make sure that the API server is configured not to send requests to cluster services through the proxy. You can check that with the following command:

$ kubectl describe pod kube-apiserver --namespace kube-system | grep -i no_proxy | grep "\.svc"

In case there’s no output and your cluster was deployed with kubeadm open /etc/kubernetes/manifests/kube-apiserver.yaml at the control plane nodes and append .svc and .svc.cluster.local to the no_proxy environment variable:

apiVersion: v1
kind: Pod
metadata:
  ...
spec:
  containers:
  - command:
    - kube-apiserver
    - --advertise-address=10.237.71.99
    ...
    env:
    - name: http_proxy
      value: http://proxy.host:8080
    - name: https_proxy
      value: http://proxy.host:8433
    - name: no_proxy
      value: 127.0.0.1,localhost,.example.com,10.0.0.0/8,.svc,.svc.cluster.local
    ...

Note: To build clusters using kubeadm with the right no_proxy settings from the very beginning, set the cluster service names to $no_proxy before kubeadm init:

$ export no_proxy=$no_proxy,.svc,.svc.cluster.local

Deployment

To deploy the webhook with cert-manager, run

$ kubectl apply -k https://github.com/intel/intel-device-plugins-for-kubernetes/deployments/sgx_admissionwebhook/overlays/default-with-certmanager?ref=main