boot.ps1

$ts = (Get-Date).toString("yyyyMMdd-HHmmss")
$logfile = "C:\Users\Administrator\log-metadata-$ts.txt"
$server = "http://169.254.1.1:8080"
$name = $env:computername
$if = Get-WmiObject win32_networkadapterconfiguration | where -property ipenabled
$q = $server + "/mac/" + $if.macaddress

Function Log-Write {
    Param ([string]$msg)
    Add-Content $logfile -value $msg
}

Log-Write "[+] Requesting instance metatada: $q"

try {
    $config = (Invoke-WebRequest $q).content | ConvertFrom-Json
    if (Get-Member -InputObject $config -Name name -MemberType Properties) {
        if ($config.name -eq $name) {
            Log-Write "[+] Hostname ok: $name"
        } else {
            Log-Write "[+] Hostname incorrect: $name / $($config.name)"
            Log-Write "[+] Resetting hostname"
            Rename-Computer -ComputerName $name -NewName $config.name
            Log-Write "[+] Restarting"
            Restart-Computer -Force
        }
    } elseif (Get-Member -InputObject $config -Name error -MemberType Properties) {
        Log-Write "[-] ERROR: $($config.error)"
    } else {
        Log-Write "[-] ERROR: Invalid response"
    }
} catch {
    Log-Write "[-] ERROR: $($error[0]) [$q]"
}

install-task.ps1

New-Item -Path "C:\Program Files\VMBoot" -ItemType Directory -Force

@"

`$ts = (Get-Date).toString("yyyyMMdd-HHmmss")
`$logfile = "C:\log-vmboot-`$ts.txt"
`$server = "http://169.254.1.1:8080"
`$name = `$env:computername
`$if = Get-WmiObject win32_networkadapterconfiguration | where -property ipenabled
`$q = `$server + "/mac/" + `$if.macaddress

Function Log-Write {
    Param ([string]`$msg)
    Add-Content `$logfile -value `$msg
}

Log-Write "[+] Requesting instance metatada: `$q"

try {
    `$config = (Invoke-WebRequest -UseBasicParsing `$q).content | ConvertFrom-Json
    if (Get-Member -InputObject `$config -Name name -MemberType Properties) {
        if (`$config.name -eq `$name) {
            Log-Write "[+] Hostname ok: `$name"
        } else {
            Log-Write "[+] Hostname incorrect: `$name / `$(`$config.name)"
            Log-Write "[+] Resetting hostname"
            Rename-Computer -ComputerName `$name -NewName `$config.name
            Log-Write "[+] Restarting"
            Restart-Computer -Force
        }
    } elseif (Get-Member -InputObject `$config -Name error -MemberType Properties) {
        Log-Write "[-] ERROR: `$(`$config.error)"
    } else {
        Log-Write "[-] ERROR: Invalid response"
    }
} catch {
    Log-Write "[-] ERROR: `$(`$error[0]) [`$q]"
}
"@ | Out-File "C:\Program Files\VMBoot\boot.ps1"

$name = "VMBoot"
$action = New-ScheduledTaskAction -Execute powershell.exe -Argument '-executionpolicy bypass -f "C:\Program Files\VMBoot\boot.ps1"'
$trigger = New-ScheduledTaskTrigger -AtStartup 
$principal = New-ScheduledTaskPrincipal -UserId SYSTEM -LogonType ServiceAccount -RunLevel Highest
$settings = New-ScheduledTaskSettingsSet -RunOnlyIfNetworkAvailable

Register-ScheduledTask -TaskName $name -Action $action -Trigger $trigger -Settings $settings -Principal $principal

metadata.py

from bottle import Bottle
from tinydb import TinyDB,Query,JSONStorage

class ReadOnlyJSONStorage(JSONStorage):
    def __init__(self, path, **kwargs):
        super(JSONStorage, self).__init__()
        self.kwargs = kwargs
        self._handle = open(path, 'r')
    def write(self, data):
        raise NotImplementedError('TinyDB Instance Read Only')

db = TinyDB('/vm/.metadata/vm.json',storage=ReadOnlyJSONStorage)
vm = Query()
app = Bottle()

@app.route('/')
def index():
    return "Index"

@app.route('/mac/<address>')
def name(address):
    meta = db.get(vm.config.network0_mac == address.lower())
    if meta:
        return meta
    else:
        return { 'error': 'MAC address not found' }

run.sh

#!/bin/sh

set -e

tmux new-session -s vm-metadata -d \
                        'python /root/vm/vmconf.py
                         while :; do
                             echo /vm | entr -pd python /root/vm/vmconf.py
                         done'

tmux split-window -t vm-metadata -v \
                        'su -c daemon -m nobody -c "python -mbottle -b 169.254.1.1:8080 metadata:app"'

vmconf.py

import glob,os.path,re,shlex,sys,time

from tinydb import TinyDB,Query

os.umask(int('022',8))
db = TinyDB('/vm/.metadata/vm.json',indent=2)
vm = Query()

print(time.asctime() + " [+] Updating /vm/.metadata/vm.json")

for config_file in glob.glob('/vm/*/*.conf'):
    config = {}
    name = os.path.splitext(os.path.basename(config_file))[0]
    with open(config_file) as f:
        for l in f:
            if re.match('^[a-z]\w+=',l):
                option,value = l.split('=',1)
                value = shlex.split(value)[0]
                config[option] = value
    db.upsert({'name':name,'config':config},vm.name == name)