Monitoring with PowerShell: Monitoring WVD availability

We’re in the middle of WVD deployment at my MSP. This client is located all over the world and needed an easy way to manage virtual desktops over many regions. This deployment actually got me thinking about how monitoring the WVD environment should be done.

We found that the WVD agent on the VMs at times did not finish the upgrade correctly, or that session hosts became unavailable at inopportune times such as when there is a high logon load. Of course we could’ve setup some Azure Alerts for this but that would be forgoing our RMM system as the single source of alerts, so as always; in comes PowerShell.

As you can’t directly retrieve the information if a session host is available from the VMs themselves I’ve made a script that checks their status via the Azure management plane, it picks up if the updates have been installed correctly, heartbeats aren’t missed, and of course if the session host is actually available. As we’ve also had issues in the past with people forgetting to remove Drain Mode from a WVD pool I’ve also added this.

The Script

The script checks all tenants that are in Lighthouse, if you haven’t configured lighthouse yet, check out my manual here. You can change the alerts to whichever you’d like.

######### Secrets #########S
$ApplicationId = 'AppID'
$ApplicationSecret = 'ApplicationSecret' | ConvertTo-SecureString -Force -AsPlainText
$TenantID = 'YourTenantID'
$RefreshToken = 'yourrefreshtoken'
$UPN = "UPN-Used-To-Generate-Tokens"
######### Secrets #########
If (Get-Module -ListAvailable -Name Az.DesktopVirtualization) { 
    Import-module Az.DesktopVirtualization
}
Else { 
    Install-PackageProvider NuGet -Force
    Set-PSRepository PSGallery -InstallationPolicy Trusted
    Install-Module -Name Az.DesktopVirtualization -force
}
$credential = New-Object System.Management.Automation.PSCredential($ApplicationId, $ApplicationSecret)
$azureToken = New-PartnerAccessToken -ApplicationId $ApplicationID -Credential $credential -RefreshToken $refreshToken -Scopes 'https://management.azure.com/user_impersonation' -ServicePrincipal -Tenant $TenantId
$graphToken = New-PartnerAccessToken -ApplicationId $ApplicationID -Credential $credential -RefreshToken $refreshToken -Scopes 'https://graph.microsoft.com/.default' -ServicePrincipal -Tenant $TenantId
 
Connect-Azaccount -AccessToken $azureToken.AccessToken -GraphAccessToken $graphToken.AccessToken -AccountId $upn -TenantId $tenantID
$Subscriptions = Get-AzSubscription  | Where-Object { $_.State -eq 'Enabled' } | Sort-Object -Unique -Property Id
$SessionHostState = foreach ($Sub in $Subscriptions) {
    $null = $Sub | Set-AzContext

    $WVDHostPools = Get-AzResource -ResourceType 'Microsoft.DesktopVirtualization/hostpools'
    if (!$WVDHostpools) {
        write-host "No hostpool found for tenant $($Sub.name)"
        continue
    }
    write-host "Found hostpools. Checking current availibility status"
    foreach ($HostPool in $WVDHostPools) {
        $AllHPState = get-AzWvdsessionhost -hostpoolname $Hostpool.name -resourcegroupname $hostpool.resourcegroupname 
        Foreach ($State in $AllHPState) {
            [PSCustomObject]@{
                HostName         = $State.Name
                Available        = $State.Status
                Heartbeat        = $State.LastHeartBeat
                UpdateState      = $State.UpdateState
                LastUpdate       = $State.LastUpdateTime
                AllowNewSessions = $State.AllowNewSession
                Subscription     = $Sub.Name
            
            }
        }
    }

}

#Check for WVD Session hosts that have issues updating the agent:

if (($SessionHostState | Where-Object { $_.UpdateState -ne 'Succeeded' })) {
    write-host "Unhealthy - Some session hosts have not updated the Agent correctly."
    $SessionHostState | Where-Object { $_.UpdateState -ne 'Succeeded' }
}
else {
    write-host "Healthy - Session hosts all updated."   
}


#Check for unavailable hosts
if (($SessionHostState | Where-Object { $_.Available -ne 'Available' })) {
    write-host "Unhealthy - Some session hosts are unavailable."
    $SessionHostState | Where-Object { $_.Available -ne 'Available' }
}
else {
    write-host "Healthy - Session hosts all updated."   
}

#Check for hosts in drain mode
if (($SessionHostState | Where-Object { $_.AllowNewSessions -eq $false })) {
    write-host "Unhealthy - Some session hosts are in drain mode"
    $SessionHostState | Where-Object { $_.AllowNewSessions -eq $false }
}
else {
    write-host "Healthy - No sessionhosts in drain mode."   
}

And that’s it. As always, Happy PowerShelling!

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