Source Code

$SUBSCRIPTION_ID='' # Provide a valid subscription id
$CLUSTER_NAME='hostprocess-cluster'
$LOCATION='westus2'
$API_MODEL='hostprocess-cluster.json'

# Creates the resource group which will house your cluster
az group create --subscription $SUBSCRIPTION_ID --location $LOCATION --name $CLUSTER_NAME

# Creates an Azure Service Principal to let AKS-Engine deploy resources (your cluster) to your resource group
$AZSP=az ad sp create-for-rbac --name win-cluster-service-principal --role="Owner" --scopes="/subscriptions/$SUBSCRIPTION_ID/resourceGroups/$CLUSTER_NAME" -o json | ConvertFrom-Json
$CLIENT_ID=$AZSP.appId
$CLIENT_SECRET=$AZSP.password

# Let azure permissions propogate before creating cluster
Start-Sleep -Seconds 180

# Create a hostprocess capable kubernetes cluster using AKS-Engine
.\aks-engine deploy `
    --subscription-id $SUBSCRIPTION_ID  `
    --client-id $CLIENT_ID `
    --client-secret $CLIENT_SECRET `
    --resource-group $CLUSTER_NAME `
    --dns-prefix $CLUSTER_NAME `
    --location $LOCATION `
    --api-model $API_MODEL `
    --force-overwrite

{
    "apiVersion": "vlabs",
    "properties": {
        "orchestratorProfile": {
            "orchestratorType": "Kubernetes",
            "orchestratorRelease": "1.23",
            "kubernetesConfig": {
                "networkPlugin": "azure",
                "apiServerConfig": {
                    "--feature-gates": "WindowsHostProcessContainers=true"
                },
                "kubeletConfig": {
                    "--feature-gates": "WindowsHostProcessContainers=true"
                },
                "containerRuntime": "containerd",
                "windowsContainerdURL": "https://github.com/kubernetes-sigs/sig-windows-tools/releases/download/windows-containerd-nightly/windows-containerd.tar.gz",
                "loadBalancerSku": "basic"
            }
        },
        "masterProfile": {
            "count": 1,
            "vmSize": "Standard_D2_v2",
            "availabilityProfile": "AvailabilitySet",
            "platformUpdateDomainCount": 1
        },
        "agentPoolProfiles": [
            {
                "name": "windowspool",
                "count": 1,
                "vmSize": "Standard_D8s_v3",
                "availabilityProfile": "VirtualMachineScaleSets",
                "osType": "Windows",
                "enableVMSSNodePublicIP": true
            }
        ],
        "windowsProfile": {
            "adminUsername": "azureuser",
            "adminPassword": "password1234$",
            "sshEnabled": true,
            "enableAutomaticUpdates": true,
            "WindowsPublisher": "microsoft-aks",
            "WindowsOffer": "aks-windows",
            "WindowsSku": "2019-datacenter-core-ctrd-2108",
            "imageVersion": "17763.2061.210830"
        },
        "linuxProfile": {
            "adminUsername": "azureuser",
            "ssh": {
                "publicKeys": [
                    {
                        "keyData": ""
                    }
                ]
            }
        }
    }
}

package main

import (
	"fmt"
	"io/ioutil"
	"os"
	"time"
)

func main() {
	hostFileToReadLocation := os.Args[1]
	hostFileToWriteLocation := os.Args[2]

	fmt.Printf("host file to read: %s\n", hostFileToReadLocation)
	fmt.Printf("host file to write: %s\n", hostFileToWriteLocation)

	// Read host file from inside the container!
	content, err := ioutil.ReadFile(hostFileToReadLocation)
	if err != nil {
		fmt.Printf("Error from reading: %v\n", err)
	}
	text := string(content)
	fmt.Println(text)

	// Write to host file from inside the container!
	f, err := os.OpenFile(hostFileToWriteLocation, os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0600)
	if err != nil {
		fmt.Printf("Error opening file to write: %v\n", err)
	}
	if _, err = f.WriteString("Hello from the container!\n"); err != nil {
		fmt.Printf("Error writing to file: %v\n", err)
	}

	// Sleep
	time.Sleep(1 * time.Hour)
}

# Use golang image to build binary
FROM golang:1.17 AS builder

# Make a working directory
WORKDIR /usr/local/app

# Copy the source code into the container
COPY src/ .

# Build the app
RUN go build app.go

# Copy the app binary into the final container image
FROM mcr.microsoft.com/windows/nanoserver:1809
COPY --from=builder /usr/local/app/app.exe \
    /usr/local/bin/app.exe

ENTRYPOINT ["/usr/local/bin/app.exe"]

docker build -t windowspodfilemount:v1.0.0 -f Dockerfile .

apiVersion: v1
kind: Pod
metadata:
  name: hostprocesspod
spec:
  nodeSelector:
    kubernetes.io/os: windows
  securityContext:
    windowsOptions:
      hostProcess: true
      runAsUserName: "NT AUTHORITY\\SYSTEM" # This lets the pod have elevated permissions
  hostNetwork: true
  containers:
  - name: winpodfilemount
    image: coolstercodes.azurecr.io/windowspodfilemount:v1.0.0
    imagePullPolicy: Always
    args: ["C:\\users\\azureuser\\hostfile.txt", "C:\\users\\azureuser\\hostfile.txt"]
    command: ["%CONTAINER_SANDBOX_MOUNT_POINT%/usr/local/bin/app.exe"]

.\kubectl --kubeconfig .\_output\hostprocess-cluster\kubeconfig\kubeconfig.westus2.json apply -f hostprocesspod.yaml

.\kubectl --kubeconfig .\_output\hostprocess-cluster\kubeconfig\kubeconfig.westus2.json logs hostprocesspod