# hyperv-vm-heartbeat.ps1 — per-VM heartbeat + state on a Hyper-V host.
# Requires the Hyper-V module (RSAT-Hyper-V-Tools or the role installed).

$Url = "YOUR_URL/hyperv"

try {
  $VMs = Get-VM -ErrorAction Stop
} catch {
  $Body = (@{ hostname = $env:COMPUTERNAME; error = "$($_.Exception.Message)" }) | ConvertTo-Json -Compress
  Invoke-RestMethod -Uri $Url -Method Post -Body $Body -ContentType "application/json" -TimeoutSec 15 | Out-Null
  exit 1
}

$Stats        = @{}
$AnyUnhealthy = $false
foreach ($vm in $VMs) {
  $hb        = "$($vm.Heartbeat)"
  $state     = "$($vm.State)"
  # 'OkApplicationsHealthy' or 'OkApplicationsUnknown' both count as healthy;
  # 'NoContact' / 'LostCommunication' / null mean the guest agent is silent.
  $healthy   = ($state -eq 'Running' -and $hb -match '^Ok')
  $Stats[$vm.Name] = @{
    state           = $state
    heartbeat       = $hb
    uptime_seconds  = if ($vm.Uptime) { [int]$vm.Uptime.TotalSeconds } else { 0 }
    healthy         = $healthy
  }
  if (-not $healthy -and $state -eq 'Running') { $AnyUnhealthy = $true }
}

$Body = (@{
  hostname       = $env:COMPUTERNAME
  vm_count       = $VMs.Count
  vms            = $Stats
  any_unhealthy  = $AnyUnhealthy
}) | ConvertTo-Json -Compress -Depth 5

Invoke-RestMethod -Uri $Url -Method Post -Body $Body `
  -ContentType "application/json" -TimeoutSec 15 | Out-Null