Install-VMInsights.ps1

<#PSScriptInfo

.VERSION 1.10.2

.GUID 76a487ef-47bf-4537-8942-600a66a547b1

.AUTHOR vpidatala@microsoft.com

.COMPANYNAME Microsoft Corporation

.COPYRIGHT Microsoft Corporation. All rights reserved.

.TAGS 

.LICENSEURI 

.PROJECTURI 

.ICONURI 

.EXTERNALMODULEDEPENDENCIES 

.REQUIREDSCRIPTS 

.EXTERNALSCRIPTDEPENDENCIES 

.RELEASENOTES
Addressed an issue with using a User Assigned Managed Identity
when a VM or VMSS already has a System or User Assigned Managed Identity.

#> 

#Requires -Module @{ ModuleName = 'Az.Compute'; ModuleVersion = '7.1.0' }
#Requires -Module @{ ModuleName = 'Az.Resources'; ModuleVersion = '6.12.1' }
#Requires -Module @{ ModuleName = 'Az.Accounts'; ModuleVersion = '2.13.2' }
#Requires -Module @{ ModuleName = 'Az.PolicyInsights'; ModuleVersion = '1.6.4' }
#Requires -Module @{ ModuleName = 'Az.Monitor'; ModuleVersion = '5.0.0' }
#Requires -Module @{ ModuleName = 'Az.ManagedServiceIdentity'; ModuleVersion = '1.2.0' }



<#
.SYNOPSIS
This script installs VM extensions for Log Analytics/Azure Monitoring Agent (AMA) and Dependency Agent if needed for VM Insights.
If AMA is onboarded, a Data Collection Rule (DCR) and a User Assigned Managed Identity (UAMI) is also associated with the VM's and VMSS.

.DESCRIPTION
This script installs or re-configures the following on VM's and VMSS under a Subscription.
1. Log Analytics VM Extension configured to supply Log Analytics Workspace and Dependency Agent VM Extension.
2. Azure Monitor Agent along with Data Collection Rule association, User Assigned Managed Identity, and Dependency Agent VM Extension (optional).


Scope can further narrowed down to :
- Resource Group
- Specific VM/VMSS
- Policy Assignment Scope

Script will show you list of VM's/VMSS that will apply to and let you confirm to continue.
Use -Approve Switch to run without prompting, if all required parameters are provided.

If the Log Analyitcs Agent extension is already configured with a workspace, use -ReInstall Switch to update the workspace.
Use -WhatIf to get info about expected effect of the commands in the script.

.PARAMETER SubscriptionId
Subscription identifier for the VMs or VMSS
If using PolicyAssignmentName parameter, VMs part of the parameter SubscriptionId are considered.

.PARAMETER ResourceGroup
<Optional> Name of the Resource Group of VMs or VMSS. It accepts wildcard characters. The default behavior is to match all.

.PARAMETER PolicyAssignmentName
<Optional> Only include VMs associated with this policy.


.PARAMETER Name
<Optional> Name qualifier to match on VM/VMSS's name in the scope. It accepts wildcard characters. The default behavior is to match all.

.PARAMETER TriggerVmssManualVMUpdate
<Optional> Set this flag to trigger update of VM instances in a scale set whose upgrade policy is set to Manual.

.PARAMETER Approve
<Optional> Set this flag to provide the approval for the installation to start with no confirmation prompt for the listed VM's/VMSS.

.PARAMETER Whatif
<Optional> Set this flag to get info about expected effect of the commands in the script.

.PARAMETER Confirm
<Optional> Set this flag to confirm each VM / VMSS.



.PARAMETER WorkspaceId
Log Analytics WorkspaceID (GUID).

.PARAMETER WorkspaceKey
Log Analytics Workspace primary or secondary key.

.PARAMETER ReInstall
<Optional> Set this flag to trigger removal of existing Log analytics extension and re-installation to migrate log analytics workspaces. 


.PARAMETER DcrResourceId
Data Collection Rule (DCR) azure resource ID identifier.

.PARAMETER UserAssignedManagedIdentityResourceGroup
Name of User Assigned Managed Identity (UAMI) resource group.

.PARAMETER UserAssignedManagedIdentityName
Name of User Assigned Managed Identity (UAMI).

.PARAMETER ProcessAndDependencies
<Optional> Set this flag to onboard Dependency Agent with Azure Monitoring Agent (AMA) settings.

.EXAMPLE
Install-VMInsights.ps1 -WorkspaceId <WorkspaceId> -WorkspaceKey <WorkspaceKey> -SubscriptionId <SubscriptionId> -ResourceGroup <ResourceGroup>
Onboard VMI for all VM's or VMSS in a Resource Group in a subscription with Legacy Agent (LA).

.EXAMPLE
Install-VMInsights.ps1 -WorkspaceId <WorkspaceId> -WorkspaceKey <WorkspaceKey> -SubscriptionId <SubscriptionId> -ResourceGroup <ResourceGroup> -ReInstall
Specify ReInstall to switch workspace with Legacy Agent (Linux) - OMSAgent.

.EXAMPLE
Install-VMInsights.ps1 -WorkspaceId <WorkspaceId> -WorkspaceKey <WorkspaceKey> -SubscriptionId <SubscriptionId> -PolicyAssignmentName a4f79f8ce891455198c08736
Specify PolicyAssignmentName to onboard VMI for VMs part of the policy assignment scope with Legacy Agent (LA).

.EXAMPLE
Install-VMInsights.ps1 -SubscriptionId <SubscriptionId> -ResourceGroup <ResourceGroup>  -DcrResourceId <DataCollectionRuleResourceId> -UserAssignedManagedIdentityName <UserAssignedIdentityName> -UserAssignedManagedIdentityResourceGroup <UserAssignedIdentityResourceGroup>
Onboard VMI for all VM's or VMSS in a Resource Group in a subscription with Azure Monitoring Agent (AMA).
Specify DcrResourceId to associate a data collection rule with VM or VMSS
Specify UserAssignedManagedIdentityName and UserAssignedManagedIdentityResourceGroup for AMA authentication purposes.

.EXAMPLE
Install-VMInsights.ps1 -SubscriptionId <SubscriptionId> -ResourceGroup <ResourceGroup> -ProcessAndDependencies -DcrResourceId <DataCollectionRuleResourceId> -UserAssignedManagedIdentityName <UserAssignedIdentityName> -UserAssignedManagedIdentityResourceGroup <UserAssignedIdentityResourceGroup>
The above command will onboard Assign a UAMI to a VM/VMss for AMA, Onboard AMA and associate a DCR with the VM/Vmss
Specify ProcessAndDependencies to onboard VM's or VMSS with Dependency Agent (DA).

.EXAMPLE
Install-VMInsights.ps1 -SubscriptionId <SubscriptionId> -PolicyAssignmentName a4f79f8ce891455198c08736  -DcrResourceId <DataCollectionRuleResourceId> -UserAssignedManagedIdentityName <UserAssignedIdentityName> -UserAssignedManagedIdentityResourceGroup <UserAssignedIdentityResourceGroup>
Specify PolicyAssignmentName to onboard VMI for VMs part of the policy assignment scope with Azure Monitoring Agent (AMA).

.LINK
This script is posted to and further documented at the following location :
http://aka.ms/OnBoardVMInsights
#>

<#CmdletBinding ConfirmImpact level Info : High - Customer data-flow disruptive action.
                                           Medium - Everything else that changes the system configuration. 
#>
#Assumption - The script assumes the entity running the script has access to all VMs/VMSS in the script.
[CmdletBinding(SupportsShouldProcess = $True, ConfirmImpact = 'High')]
param(
    [Parameter(mandatory = $True)][String]$SubscriptionId,
    [Parameter(mandatory = $False)][Switch]$TriggerVmssManualVMUpdate,
    [Parameter(mandatory = $False)][Switch]$Approve,
    [Parameter(mandatory = $False)][String]$ResourceGroup = "*",
    [Parameter(mandatory = $False)][String]$Name = "*",
    [Parameter(mandatory = $False)][String]$PolicyAssignmentName,
    
    [Parameter(mandatory = $False, ParameterSetName = 'AzureMonitoringAgent')][Switch]$ProcessAndDependencies,
    [Parameter(mandatory = $True, ParameterSetName = 'AzureMonitoringAgent')][String]$DcrResourceId,
    [Parameter(mandatory = $True, ParameterSetName = 'AzureMonitoringAgent')][String]$UserAssignedManagedIdentityResourceGroup,
    [Parameter(mandatory = $True, ParameterSetName = 'AzureMonitoringAgent')][String]$UserAssignedManagedIdentityName,

    [Parameter(mandatory = $True,  ParameterSetName = 'LogAnalyticsAgent')][String]$WorkspaceId,
    [Parameter(mandatory = $True,  ParameterSetName = 'LogAnalyticsAgent')][String]$WorkspaceKey,
    [Parameter(mandatory = $False, ParameterSetName = 'LogAnalyticsAgent')][Switch]$ReInstall
)

$ErrorActionPreference = "Stop"

class CustomerSkip : System.Exception {
    CustomerSkip() : base () {}
}

class FatalException : System.Exception {
    FatalException([String]$errorMessage, [Exception]$innerException) : base($errorMessage, $innerException) {}
}

class VirtualMachineException : System.Exception {
    VirtualMachineException(<#[Microsoft.Azure.Commands.Compute.Models.PSVirtualMachine]#>$vmObject,
                            [String]$errorMessage,
                            [Exception]$innerException) : base("$(FormatVmIdentifier -VMObject $vmObject) : $errorMessage", $innerException) {}
}

class VirtualMachineScaleSetException : System.Exception {
    VirtualMachineScaleSetException(<#[Microsoft.Azure.Commands.Compute.Automation.Models.PSVirtualMachineScaleSet]#>$vmssObject,
                                    [String]$errorMessage,
                                    [Exception]$innerException) : base("$(FormatVmssIdentifier -VMssObject $vmssObject) : $errorMessage", $innerException) {}
}

class ResourceGroupDoesNotExist : System.Exception {
    ResourceGroupDoesNotExist ([String]$rgName, [Exception]$innerException) : base("$rgName : Resource Group does not exist", $innerException) {}
}

class VirtualMachineUnknownException : VirtualMachineException {
    VirtualMachineUnknownException(<#[Microsoft.Azure.Commands.Compute.Models.PSVirtualMachine]#>$vmObject,
                                   [String]$errorMessage,
                                   [Exception]$innerException) : base($vmObject, $errorMessage, $innerException) {}
}

class VirtualMachineDoesNotExist : VirtualMachineException {
    VirtualMachineDoesNotExist (<#[Microsoft.Azure.Commands.Compute.Models.PSVirtualMachine]#>$vmObject,
                                [Exception]$innerException) : base($vmObject, "VM does not exist", $innerException) {}
}

class VirtualMachineOperationFailed : VirtualMachineException {
    VirtualMachineOperationFailed(<#[Microsoft.Azure.Commands.Compute.Models.PSVirtualMachine]#>$vmObject,
                                  [String]$errorMessage) : base($vmObject, $errorMessage, $null) {}
}

class VirtualMachinePoweredDown : VirtualMachineException {
    VirtualMachinePoweredDown(<#[Microsoft.Azure.Commands.Compute.Models.PSVirtualMachine]#>$vmObject,
                              [Exception]$innerException) : base($vmObject, "VM is powered down", $innerException) {}
}

class VirtualMachineExtensionError : VirtualMachineException {
    VirtualMachineExtensionError (<#[Microsoft.Azure.Commands.Compute.Models.PSVirtualMachine]#>$vmObject,
                                  [String]$extension,
                                  [Exception]$innerException) : base($vmObject, "VM extension error for $extension`n$($innerException.Message)", $innerException) {}
}

class VirtualMachineScaleSetUnknownException : VirtualMachineScaleSetException {
    VirtualMachineScaleSetUnknownException(<#[Microsoft.Azure.Commands.Compute.Automation.Models.PSVirtualMachineScaleSet]#>$vmssObject,
                                           [String]$errorMessage,
                                           [Exception]$innerException) : base($vmssObject, $errorMessage, $innerException) {}
}

class VirtualMachineScaleSetDoesNotExist : VirtualMachineScaleSetException {
    VirtualMachineScaleSetDoesNotExist (<#[Microsoft.Azure.Commands.Compute.Automation.Models.PSVirtualMachineScaleSet]#>$vmssObject,
                                        [Exception]$innerException) : base($vmssObject, "VMSS does not exist", $innerException) {}
}

class VirtualMachineScaleSetOperationFailed : VirtualMachineScaleSetException {
    VirtualMachineScaleSetOperationFailed(<#[Microsoft.Azure.Commands.Compute.Automation.Models.PSVirtualMachineScaleSet]#>$vmssObject,
                                          [String]$errorMessage) : base($vmssObject, $errorMessage, $null) {}
}

class VirtualMachineScaleSetExtensionError : VirtualMachineScaleSetException {
    VirtualMachineScaleSetExtensionError (<#[Microsoft.Azure.Commands.Compute.Automation.Models.PSVirtualMachineScaleSet]#>$vmssObject,
                                          [Exception]$innerException) : base($vmssObject, "VMSS extension error`n$($innerException.Message)", $innerException) {}
}

class DataCollectionRuleForbidden : FatalException {
    DataCollectionRuleForbidden([String]$dcrResourceId,
                                [Exception]$innerException) : base("$dcrResourceId : Access to Data Collection Rule is forbidden", $innerException) {}
}

class DataCollectionRuleDoesNotExist : FatalException {
    DataCollectionRuleDoesNotExist([String]$dcrResourceId,
                                   [Exception]$innerException) : base("$dcrResourceId : Data Collection Rule does not exist.", $innerException) {}
}

class DataCollectionRuleIncorrect : FatalException {
    DataCollectionRuleIncorrect([String]$dcrResourceId,
                                [Exception]$innerException) : base("$dcrResourceId : Data Collection Rule incorrect format.", $innerException) {}
}

class UserAssignedManagedIdentityDoesNotExist : FatalException {
    UserAssignedManagedIdentityDoesNotExist($uamiName,
                                            [Exception]$innerException) : base("$uamiName : User Assigned Managed Identity does not exist.", $innerException) {}
}

class UserAssignedManagedIdentityResourceGroupDoesNotExist : FatalException {
    UserAssignedManagedIdentityResourceGroupDoesNotExist($uamiResourceGroup,
                                                         [Exception]$innerException) : base("$uamiResourceGroup : User Assigned Managed Identity Resource Group does not exist.", $innerException) {}
}

class UserAssignedManagedIdentityUnknownException : FatalException {
    UserAssignedManagedIdentityUnknownException([String]$errorMessage,
                                                [Exception]$innerException) : base($errorMessage, $innerException) {}
}

class ResourceGroupTableElement {
    [System.Collections.ArrayList] $VirtualMachineList = [System.Collections.ArrayList]::new()
    [System.Collections.ArrayList] $VirtualMachineScaleSetList = [System.Collections.ArrayList]::new()
}

class OnboardingCounters {
    [Decimal]$Succeeded = 0
    [Decimal]$Total = 0
    [Decimal]$Skipped = 0
    [Decimal]$VMSSInstanceUpgradeFailure = 0
}

# Log Analytics Extension constants
Set-Variable -WhatIf:$False -Confirm:$False -Name laExtensionMap -Option Constant -Value @{ 
    "Windows" = @{  ExtensionType = "MicrosoftMonitoringAgent"
                    TypeHandlerVersion = "1.0"
                    Publisher = "Microsoft.EnterpriseCloud.Monitoring"
                }
    "Linux" =  @{   ExtensionType  = "OmsAgentForLinux"
                    TypeHandlerVersion  = "1.6"
                    Publisher = "Microsoft.EnterpriseCloud.Monitoring"
                }
}
Set-Variable -WhatIf:$False -Confirm:$False -Name laDefaultExtensionName -Option Constant -Value "MMAExtension"

# Azure Monitoring Agent Extension constants
Set-Variable -WhatIf:$False -Confirm:$False -Name amaExtensionConstantMap -Option Constant -Value @{ 
       "Windows" = @{  ExtensionType = "AzureMonitorWindowsAgent"
                       TypeHandlerVersion = "1.16"
                       Publisher = "Microsoft.Azure.Monitor" 
                    }
       "Linux" =   @{  ExtensionType = "AzureMonitorLinuxAgent" 
                       TypeHandlerVersion = "1.16"
                       Publisher = "Microsoft.Azure.Monitor"
                    }
}
Set-Variable -WhatIf:$False -Confirm:$False -Name amaDefaultExtensionName -Option Constant -Value "AzureMonitoringAgent"

# Dependency Agent Extension constants
Set-Variable -WhatIf:$False -Confirm:$False -Name daExtensionConstantsMap -Option Constant -Value @{
    "Windows" = @{ ExtensionType = "DependencyAgentWindows"
                   TypeHandlerVersion = "9.10"
                   Publisher = "Microsoft.Azure.Monitoring.DependencyAgent"
                }
    "Linux" = @{ ExtensionType = "DependencyAgentLinux"
                 TypeHandlerVersion = "9.10"
                 Publisher = "Microsoft.Azure.Monitoring.DependencyAgent"
               }
}
Set-Variable -WhatIf:$False -Confirm:$False -Name daDefaultExtensionName -Option Constant -Value "DA-Extension"
$extensionVmDefaultUpgradeSettings = @{
    EnableAutomaticUpgrade = $True
    DisableAutoUpgradeMinorVersion = $False
}

Set-Variable -WhatIf:$False -Confirm:$False -Name unknownExceptionVirtualMachineConsequentCounterLimit -Option Constant -Value 3
Set-Variable -WhatIf:$False -Confirm:$False -Name unknownExceptionVirtualMachineScaleSetConsequentCounterLimit -Option Constant -Value 3
Set-Variable -WhatIf:$False -Confirm:$False -Name unknownExceptionTotalCounterLimit -Option Constant -Value 6

#Presence of DCR Resource Id indicates AMA onboarding.
$isAma = "" -ne $DcrResourceId

#
# FUNCTIONS
#
function PrintSummaryMessage {
    <#
	.SYNOPSIS
	Print the Total of eligible VM/VMSS, number of succeeded and failed.
	#>
    param (
        [Parameter(mandatory = $True)]
        [OnboardingCounters]
        $OnboardingCounters
    )
    Write-Host ""
    Write-Host "Summary :"
    Write-Host "Total VM/VMSS to be processed : $($OnboardingCounters.Total)"
    Write-Host "Succeeded : $($OnboardingCounters.Succeeded)"
    Write-Host "Skipped : $($OnboardingCounters.Skipped)"
    Write-Host "Failed : $($OnboardingCounters.Total - $OnboardingCounters.Skipped - $OnboardingCounters.Succeeded)"
    Write-Host "VMSS Instance Upgrade Failures : $($OnboardingCounters.VMSSInstanceUpgradeFailure)"
}

function ExtractCloudExceptionErrorMessage {
    <#
	.SYNOPSIS
	Extract error code from the Cloud Exception. 
	#>
    param
    (
        [Parameter(Mandatory=$True)]
        [System.Management.Automation.ErrorRecord]
        $ErrorRecord
    )

    if ($ErrorRecord.Exception.Message -match 'ErrorMessage *: *(.*)') {
        return $matches[1]
    }

    return $null
}

function ExtractExceptionErrorCode {
    <#
	.SYNOPSIS
	Extract error code from the Cloud Exception. 
	#>
    param
    (
        [Parameter(Mandatory=$True)]
        [System.Management.Automation.ErrorRecord]
        $ErrorRecord
    )

    if ($ErrorRecord.Exception.Message -match 'ErrorCode *: *([^\s]+)') {
        return $matches[1]
    }

    return $null
}

function ExtractExceptionPrefixErrCode {
    <#
	.SYNOPSIS
	Extract error code from the Cloud Exception. 
	#>
    param
    (
        [Parameter(Mandatory=$True)]
        [System.Management.Automation.ErrorRecord]
        $ErrorRecord
    )

    if ($ErrorRecord.Exception.Message -match '^[[]([^]]+)[]] *:') {
        return $matches[1]
    }

    return $null
}

function FormatVmIdentifier {
    <#
    .SYNOPSIS
    Format VM Information for messages
    #>
    param (
        [Parameter(Mandatory=$True)] 
        [Microsoft.Azure.Commands.Compute.Models.PSVirtualMachine]
        $VMObject
    )
    return "($($VMObject.ResourceGroupName)) $($VMObject.Name)"
}

function FormatVmssIdentifier {
    <#
    .SYNOPSIS
    Format VMSS Information for messages
    #>
    param (
        [Parameter(Mandatory=$True)] 
        [Microsoft.Azure.Commands.Compute.Automation.Models.PSVirtualMachineScaleSet]
        $VMssObject
    )
    
    return "($($VMssObject.ResourceGroupName)) $($VMssObject.Name)"
}

function IsVmAndGuestAgentUpAndHealthy {
    <#
    .SYNOPSIS
    Checks whether a VM is up and Guest agent is in a healthy state.
    #>
    param (
        [Parameter(Mandatory=$True)]
        [Microsoft.Azure.Commands.Compute.Models.PSVirtualMachine]
        $VMObject
    )
  
    try {
        $vmResourceGroupName = $VMObject.ResourceGroupName
        $vmlogheader = FormatVmIdentifier -VMObject $VMObject
        
        $vmWithStatus = Get-AzVm -ResourceGroupName $vmResourceGroupName -Name $VMObject.Name -Status
        
        $vmhealthStatusCode = $vmWithStatus.Statuses.Code
        if (!($vmhealthStatusCode -contains 'ProvisioningState/succeeded' -and $vmhealthStatusCode -contains 'PowerState/running')) {
            Write-Host "$vmlogheader : Virtual Machine is not operational - $($vmWithStatus.Statuses.DisplayStatus)"
            return $False
        }

        $guestAgentHealthCode = $vmWithStatus.VMAgent.Statuses.Code
        if (!($guestAgentHealthCode -contains 'ProvisioningState/succeeded')) {
            Write-Host "$vmlogheader : Guest Agent is not healthy - $($vmWithStatus.VMAgent.Statuses.DisplayStatus)"
            return $False
        }

        return $True
    } catch [Microsoft.Azure.Commands.Compute.Common.ComputeCloudException] {
        $errorCode = ExtractExceptionErrorCode -ErrorRecord $_
        if ($errorCode -eq "ResourceNotFound") { 
            throw [VirtualMachineDoesNotExist]::new($VMObject, $_.Exception)
        }

        if ($errorCode -eq "ResourceGroupNotFound") {
            throw [ResourceGroupDoesNotExist]::new($vmResourceGroupName, $_.Exception)  
        }

        throw [VirtualMachineUnknownException]::new($VMObject, "Failed to get status of virtual machine", $_.Exception)
    }
}

function VerboseDisplayException {
    <#
    .SYNOPSIS
    Renders customer actionable message, inner exception and stack trace to verbose stream.
    Does not throw any exceptions.
    #>
    param (
        [Parameter(Mandatory=$True)]
        [System.Management.Automation.ErrorRecord]
        $ErrorRecord
    )

    try {
        $ex = $ErrorRecord.Exception
        Write-Host "ExceptionMessage : $($ex.Message)"
        Write-Verbose "StackTrace :"
        Write-Verbose "$($ex.StackTrace)"
        while ($ex = $ex.InnerException) {
            Write-Verbose "InnerExceptionMessage : $($ex.Message)"
            Write-Verbose "StackTrace :"
            Write-Verbose "$($ex.StackTrace)"
        }
        Write-Verbose "ScriptStackTrace :" $ErrorRecord.ScriptStackTrace
    }
    catch {
        # silently ignore
    }
}

function DisplayException {
    <#
    .SYNOPSIS
    Renders customer actionable message, inner exception and stack trace to console.
    Does not throw any exceptions.
    #>
    param (
        [Parameter(Mandatory=$True)]
        [System.Management.Automation.ErrorRecord]
        $ErrorRecord
    )

    try {
        $ex = $ErrorRecord.Exception
        Write-Host "ExceptionMessage : $($ex.Message)"
        Write-Host "StackTrace :"
        Write-Host "$($ex.StackTrace)"
        while ($ex = $ex.InnerException) {
            Write-Host "InnerExceptionMessage : $($ex.Message)"
            Write-Host "StackTrace :"
            Write-Host "$($ex.StackTrace)"
        }
        Write-Host "ScriptStackTrace :" $ErrorRecord.ScriptStackTrace
    }
    catch {
        # silently ignore
    }
}

function GetRgObject {

    <#
    .SYNOPSIS
    PopulateRgHashTableVMs/VMss util function
    #>
    param(
        [Parameter(Mandatory=$True)]
        [Hashtable]
        $Rghashtable,
        [Parameter(Mandatory=$True)]
        [String]
        $ResourceGroupName
    )

    $rgTableElemObject = $Rghashtable[$ResourceGroupName]
    if ($null -eq $rgTableElemObject) {
        $rgTableElemObject = [ResourceGroupTableElement]::new()
        $Rghashtable.Add($ResourceGroupName,$rgTableElemObject)
    }

    return $rgTableElemObject
}

function PopulateRgHashTableVm {
    <#
    .SYNOPSIS
    Populate Resource Group hash table for VMs
    #>
    param(
        [Parameter(Mandatory=$True)]
        [Hashtable]
        $Rghashtable,
        [Parameter(Mandatory=$True)]
        [Microsoft.Azure.Commands.Compute.Models.PSVirtualMachine]
        $VMObject
    )

    $rgTableElemObject = GetRgObject -Rghashtable $Rghashtable -ResourceGroupName $VMObject.ResourceGroupName
    $rgTableElemObject.VirtualMachineList.Add($VMObject)  > $null
}

function PopulateRgHashTableVmss {
    <#
    .SYNOPSIS
    Populate Resource Group hash table for VMSS
    #>
    param(
        [Parameter(Mandatory=$True)]
        [Hashtable]
        $Rghashtable,
        [Parameter(Mandatory=$True)]
        [Microsoft.Azure.Commands.Compute.Automation.Models.PSVirtualMachineScaleSet]
        $VMssObject
    )

    $rgTableElemObject = GetRgObject -Rghashtable $Rghashtable -ResourceGroupName $VMssObject.ResourceGroupName
    $rgTableElemObject.VirtualMachineScaleSetList.Add($VMssObject)  > $null
}

function GetVMExtension {
    <#
	.SYNOPSIS
	Return the VM extension of specified Type and Publisher.
	#>
    param
    (
        [Parameter(mandatory = $True)]
        [Microsoft.Azure.Commands.Compute.Models.PSVirtualMachine]
        $VMObject,
        [Parameter(mandatory = $True)]
        [Hashtable]
        $ExtensionProperties
    )

    $extensionType = $ExtensionProperties.ExtensionType
    $publisher = $ExtensionProperties.Publisher

    try {
        $extensions = Get-AzVMExtension -ResourceGroupName $VMObject.ResourceGroupName -VMName $VMObject.Name
        foreach ($extension in $extensions) {
            if ($extension.ExtensionType -eq $extensionType -and $extension.Publisher -eq $publisher) {
                return $extension
            }
        }
    } catch [Microsoft.Azure.Commands.Compute.Common.ComputeCloudException] {
        $errorCode = ExtractExceptionErrorCode -ErrorRecord $_
        if ($errorCode -eq "ParentResourceNotFound") {
            throw [VirtualMachineDoesNotExist]::new($VMObject, $_.Exception)
        }
        if ($errorCode -eq "ResourceGroupNotFound") {
            throw [ResourceGroupDoesNotExist]::new($($VMObject.ResourceGroupName),$_.Exception)   
        }    
        throw [VirtualMachineUnknownException]::new($VMObject, "Failed to locate extension with type = $($publisher).$($extensionType)", $_.Exception)
    }
    
    return $null
}

function GetVMssExtension {
    <#
	.SYNOPSIS
	Return the VMSS extension of specified ExtensionType and Publisher.
	#>
    param
    (
        [Parameter(Mandatory = $True)]
        [Microsoft.Azure.Commands.Compute.Automation.Models.PSVirtualMachineScaleSet]
        $VMssObject,
        [Parameter(mandatory = $True)]
        [String]
        $ExtensionType,
        [Parameter(mandatory = $True)]
        [String]
        $Publisher
    )

    $extensions = $VMssObject.VirtualMachineProfile.ExtensionProfile.Extensions

    foreach ($extension in $extensions) {
        if ($extension.Type -eq $ExtensionType -and $extension.Publisher -eq $Publisher) {
            return $extension
        }
    }

    return $null
}

function RemoveVMExtension {
    <#
	.SYNOPSIS
	Remove a VM Extension.
	#>
    [CmdletBinding(SupportsShouldProcess = $True, ConfirmImpact = 'High')]
    param
    (
        [Parameter(mandatory = $True)]
        [Microsoft.Azure.Commands.Compute.Models.PSVirtualMachine]
        $VMObject,
        [Parameter(mandatory = $True)]
        [String]
        $ExtensionName,
        [Parameter(mandatory = $True)]
        [hashtable]
        $ExtensionProperties
    )

    $vmlogheader = FormatVmIdentifier -VMObject $VMObject
    $extensionType = $ExtensionProperties.ExtensionType
    $extensionPublisher = $ExtensionProperties.Publisher
    
    if (!$PSCmdlet.ShouldProcess($vmlogheader, "Remove $ExtensionName, type $($extensionPublisher).$($extensionType)")) {
        #-WhatIf skip processing here, return to the caller as we have completed our work.
        if ($WhatIfPreference) {
            return
        }
        throw [CustomerSkip]::new()
    }

    try {
        #Remove operation on non existent VM, extension still return a success
        $removeResult = Remove-AzVMExtension -ResourceGroupName $VMObject.ResourceGroupName `
                                             -VMName $VMObject.Name `
                                             -Name $ExtensionName -Confirm:$false -Force
    } catch [Microsoft.Azure.Commands.Compute.Common.ComputeCloudException] {
        $errorCode = ExtractExceptionErrorCode -ErrorRecord $_
        if ($errorCode -eq "ResourceGroupNotFound") {
            throw [ResourceGroupDoesNotExist]::new($VMObject.ResourceGroupName, $_.Exception)       
        } 
        
        throw [VirtualMachineUnknownException]::new($VMObject, "Failed to remove extension $ExtensionName, type $($extensionPublisher).$($extensionType)", $_.Exception)
    }
    
    if ($removeResult.IsSuccessStatusCode) {
        Write-Host "$vmlogheader : Successfully removed extension $ExtensionName, type $($extensionPublisher).$($extensionType)"
        return
    }

    throw [VirtualMachineOperationFailed]::new($VMObject, 
            "Failed to remove extension $ExtensionName, type $($extensionPublisher).$($extensionType). StatusCode = $($removeResult.StatusCode). ReasonPhrase = $($removeResult.ReasonPhrase)")
}

#VMI supports Customers onboarding DCR from different subscription to which it has access to.
#Cannot validate DCRResourceId parameter Get-AzDataCollectionRule -ResourceId is getting deprecated.        
function NewDCRAssociationVm {
    <#
	.SYNOPSIS
	Create a new DCRAssociation with VMs.
	#>
    [CmdletBinding(SupportsShouldProcess = $True, ConfirmImpact = 'Medium')]
    param
    (
        [Parameter(mandatory = $True)]
        [Microsoft.Azure.Commands.Compute.Models.PSVirtualMachine]
        $VMObject
    )

    $vmId = $VMObject.Id
    $vmlogheader = FormatVmIdentifier -VMObject $VMObject
    
    try {
        # A VM may have zero or more Data Collection Rule Associations.
        $dcrAssociationList = Get-AzDataCollectionRuleAssociation -TargetResourceId $vmId 
        foreach ($dcra in $dcrAssociationList) {
            if ($dcra.DataCollectionRuleId -eq $DcrResourceId) {
                Write-Host "$vmlogheader : Data Collection Rule Id $DcrResourceId already associated with the VM."
                return
            }
        }
    } catch [System.Management.Automation.ParameterBindingException] {
        throw [VirtualMachineDoesNotExist]::new($VMObject, $_.Exception)
    }

    if (!($PSCmdlet.ShouldProcess($vmlogheader, "Install Data Collection Rule Association"))) {
        #-WhatIf skip processing here, return to the caller as we have completed our work.
        if ($WhatIfPreference) {
            return
        }
        throw [CustomerSkip]::new()
    }

    #Customer can associate multiple DCRs to a VM.
    $dcrAssociationName = "VM-Insights-DCR-Association-$(New-Guid)"
    Write-Host "$vmlogheader : Deploying Data Collection Rule Association $dcrAssociationName"
    try {
        #BUG! To be fixed by AMCS team - New-AzDataCollectionRuleAssociation allows creating multiple DCRAs for the same {DCR,VMSS} combination.
        $dcrAssociation = New-AzDataCollectionRuleAssociation -TargetResourceId $vmId `
                                                              -AssociationName $dcrAssociationName `
                                                              -RuleId $DcrResourceId `
                                                              -Confirm:$false
    } catch [System.Management.Automation.PSInvalidOperationException] {
        $exceptionMessage = $_.Exception.Message
        
        if ($exceptionMessage.Contains('Invalid format of the resource identifier')) {
            throw [DataCollectionRuleIncorrect]::new($DcrResourceId, $_.Exception)
        } 

        if (!($exceptionMessage -match "status code '([^\s]+)'")) {
            throw [VirtualMachineUnknownException]::new($VMObject, "Failed to create Data Collection Rule Association with $DcrResourceId", $_.Exception)
        }

        $statusCode = $matches[1]
        if ($statusCode -eq 'BadRequest') {
            throw [DataCollectionRuleDoesNotExist]::new($DcrResourceId, $_.Exception)
        }
        if ($statusCode -eq 'NotFound') {
            throw [VirtualMachineDoesNotExist]::new($VMObject, $_.Exception)
        }
        if ($statusCode -eq 'Forbidden') {
            throw [DataCollectionRuleForbidden]::new($DcrResourceId, $_.Exception)     
        }

        throw [VirtualMachineUnknownException]::new($VMObject, "Failed to create Data Collection Rule Association with with $DcrResourceId. StatusCode = $statusCode", $_.Exception)
    }

    #Tmp fix task :- 21191002
    if (($null -eq $dcrAssociation) -or ($dcrAssociation -is [Microsoft.Azure.Management.Monitor.Models.ErrorResponseCommonV2Exception])) {
        throw [VirtualMachineUnknownException]::new($VMObject, "Unable to create Data Collection Rule Association with $DcrResourceId", $_.Exception)
    }

    Write-Host "$vmlogheader : Successfully created Data Collection Rule Association"
}

function NewDCRAssociationVmss {
    <#
	.SYNOPSIS
	Create a new DCR Association with VMSS.
	#>
    [CmdletBinding(SupportsShouldProcess = $True, ConfirmImpact = 'Medium')]
    param
    (
        [Parameter(mandatory = $True)]
        [Microsoft.Azure.Commands.Compute.Automation.Models.PSVirtualMachineScaleSet]
        $VMssObject
    )

    $vmsslogheader = FormatVmssIdentifier -VMssObject $VMssObject
    $vmssId = $VMssObject.Id

    try {
        # A VMSS may have zero or more Data Collection Rule Associations.
        $dcrAssociationList = Get-AzDataCollectionRuleAssociation -TargetResourceId $vmssId 
        foreach ($dcra in $dcrAssociationList) {
            if ($dcra.DataCollectionRuleId -eq $DcrResourceId) {
                Write-Host "$vmsslogheader : Data Collection Rule Id $DcrResourceId already associated with the VMSS."
                return
            }
        }
    } catch [System.Management.Automation.ParameterBindingException] {
        throw [VirtualMachineScaleSetDoesNotExist]::new($VMssObject, $_.Exception)
    }

    if (!($PSCmdlet.ShouldProcess($vmsslogheader, "Install Data Collection Rule Association"))) {
        #-WhatIf skip processing here, return to the caller as we have completed our work.
        if ($WhatIfPreference) {
            return
        }
        throw [CustomerSkip]::new()
    }

    #Customer can associate multiple DCRs to a VMSS.
    $dcrAssociationName = "VM-Insights-DCR-Association-$(New-Guid)"
    Write-Host "$vmsslogheader : Deploying Data Collection Rule Association $dcrAssociationName"
    try {
        #BUG! To be fixed by AMCS team - New-AzDataCollectionRuleAssociation allows creating multiple DCRAs for the same {DCR,VMSS} combination.
        $dcrAssociation = New-AzDataCollectionRuleAssociation -TargetResourceId $vmssId `
                                                              -AssociationName $dcrAssociationName `
                                                              -RuleId $DcrResourceId `
                                                              -Confirm:$false
    } catch [System.Management.Automation.PSInvalidOperationException] {
        $exceptionMessage = $_.Exception.Message
        
        if ($exceptionMessage.Contains('Invalid format of the resource identifier')) {
            throw [DataCollectionRuleIncorrect]::new($DcrResourceId, $_.Exception)
        } 
        
        if (!($exceptionMessage -match "status code '([^\s]+)'")) {
            throw [VirtualMachineScaleSetUnknownException]::new($VMssObject, "Failed to create Data Collection Rule Association with $DcrResourceId", $_.Exception)
        }

        $statusCode = $matches[1]
        if ($statusCode -eq 'BadRequest') {
            throw [DataCollectionRuleDoesNotExist]::new($DcrResourceId, $_.Exception)
        }
        if ($statusCode -eq 'NotFound') {
            throw [VirtualMachineScaleSetDoesNotExist]::new($VMssObject, $_.Exception)
        }
        if ($statusCode -eq 'Forbidden') {
            throw [DataCollectionRuleForbidden]::new($DcrResourceId, $_.Exception)     
        }

        throw [VirtualMachineUnknownException]::new($VMssObject, "Failed to create Data Collection Rule Association with with $DcrResourceId. StatusCode = $statusCode", $_.Exception)
    }
    #Tmp fix task :- 21191002
    if (($null -eq $dcrAssociation) -or ($dcrAssociation -is [Microsoft.Azure.Management.Monitor.Models.ErrorResponseCommonV2Exception])) {
        throw [VirtualMachineScaleSetDoesNotExist]::new($VMssObject, "Unable to create Data Collection Rule Association with $DcrResourceId", $_.Exception)
    }
}

function RetainExtensionUpgradeSettings {
    <#
	.SYNOPSIS
	Retain extension upgrade settings
	#>
    param
    (
        [Parameter(mandatory = $True)]
        [Microsoft.Azure.Commands.Compute.Models.PSVirtualMachineExtension]
        $Extension,
        [Parameter(mandatory = $True)]
        [hashtable]
        $ExtUpgradeSettings
    )

    $ExtUpgradeSettings.DisableAutoUpgradeMinorVersion = !($Extension.AutoUpgradeMinorVersion)
    $ExtUpgradeSettings.EnableAutomaticUpgrade = $Extension.EnableAutomaticUpgrade
}

function OnboardDaVm {
    <#
	.SYNOPSIS
	Onboard DA on VM, handling if already installed.
	#>
    param
    (
        [Parameter(mandatory = $True)]
        [Microsoft.Azure.Commands.Compute.Models.PSVirtualMachine]
        $VMObject,
        [Parameter(mandatory = $True)]
        [hashtable]
        $ExtensionSettings
    )

    $extensionName = $daDefaultExtensionName
    $extUpgradeSettings = $extensionVmDefaultUpgradeSettings.clone()
    $daExtensionConstantProperties = $daExtensionConstantsMap[$VMObject.StorageProfile.OsDisk.OsType.ToString()]
    $extension = GetVMExtension -VMObject $VMObject -ExtensionProperties $daExtensionConstantProperties
    # Use supplied name unless already deployed, use same name.
    if ($extension) {
        $extensionName = $extension.Name
        RetainExtensionUpgradeSettings -Extension $extension -ExtUpgradeSettings $extUpgradeSettings
        Write-Host "$(FormatVmIdentifier -VMObject $VMObject) : Extension $extensionName, type $($daExtensionConstantProperties.Publisher).$($daExtensionConstantProperties.ExtensionType) already installed. Provisioning State : $($extension.ProvisioningState)"
    }
    
    return SetVMExtension -VMObject $VMObject `
                          -ExtensionName $extensionName `
                          @daExtensionConstantProperties `
                          -ExtensionUpgradeSettings $extUpgradeSettings `
                          -ExtensionSettings $ExtensionSettings
}

function OnboardAmaVm {
    <#
	.SYNOPSIS
	Onboard AMA on VM, handling if already installed.
	#>
    param
    (
        [Parameter(mandatory = $True)]
        [Microsoft.Azure.Commands.Compute.Models.PSVirtualMachine]
        $VMObject,
        [Parameter(mandatory = $True)]
        [hashtable]
        $ExtensionSettings
    )
    
    $amaExtensionConstantProperties = $amaExtensionConstantMap[$VMObject.StorageProfile.OsDisk.OsType.ToString()]
    $extensionName = $amaDefaultExtensionName
    $extUpgradeSettings = $extensionVmDefaultUpgradeSettings.clone()
    $extension = GetVMExtension -VMObject $VMObject -ExtensionProperties $amaExtensionConstantProperties
    # Use supplied name unless already deployed, use same name.
    if ($extension) {
        $extensionName = $extension.Name
        RetainExtensionUpgradeSettings -Extension $extension -ExtUpgradeSettings $extUpgradeSettings
        Write-Host "$(FormatVmIdentifier -VMObject $VMObject) : Extension $extensionName, type = $($amaExtensionConstantProperties.Publisher).$($amaExtensionConstantProperties.ExtensionType) already installed. Provisioning State : $($extension.ProvisioningState)"
    }
    
    return SetVMExtension -VMObject $VMObject `
                          -ExtensionName $extensionName `
                          @amaExtensionConstantProperties `
                          -ExtensionUpgradeSettings $extUpgradeSettings `
                          -ExtensionSettings $ExtensionSettings
}

function OnboardLaVmWithReInstall {
    <#
	.SYNOPSIS
	Onboard LA on VM, ReInstall flag provided.
	#>
    param
    (
        [Parameter(mandatory = $True)]
        [Microsoft.Azure.Commands.Compute.Models.PSVirtualMachine]
        $VMObject,
        [Parameter(mandatory = $True)]
        [hashtable]
        $ExtensionSettings
    )

    $osType = $VMObject.StorageProfile.OsDisk.OsType.ToString()
    $laExtensionConstantProperties = $laExtensionMap[$osType]
    # Use supplied name unless already deployed, use same name.
    $extensionName = $laDefaultExtensionName
    $vmlogheader = FormatVmIdentifier -VMObject $VMObject
    $extUpgradeSettings = $extensionVmDefaultUpgradeSettings.clone()

    $extension = GetVMExtension -VMObject $VMObject -ExtensionProperties $laExtensionConstantProperties
    # Use supplied name unless already deployed, use same name.
    if ($extension) {
        $extensionName = $extension.Name
        RetainExtensionUpgradeSettings -Extension $extension -ExtUpgradeSettings $extUpgradeSettings
        Write-Host "$vmlogheader : Extension $extensionName, type $($laExtensionConstantProperties.Publisher).$($laExtensionConstantProperties.ExtensionType) already installed. Provisioning State : $($extension.ProvisioningState)"
        if ($osType -eq "Linux" -and $extension.PublicSettings) {
            $extensionPublicSettingsJson = $extension.PublicSettings | ConvertFrom-Json
            if ($extensionPublicSettingsJson.workspaceId -ne $ExtensionSettings.Settings.workspaceId) {
                Write-Host "$vmlogheader : OmsAgentForLinux requires an uninstall followed by a re-install to change the workspace."
                RemoveVMExtension -VMObject $VMObject `
                                  -ExtensionName $extensionName `
                                  -ExtensionProperties $laExtensionConstantProperties
            }
        }
    }
    
    return SetVMExtension -VMObject $VMObject `
                          -ExtensionName $extensionName `
                          @laExtensionConstantProperties `
                          -ExtensionUpgradeSettings $extUpgradeSettings `
                          -ExtensionSettings $ExtensionSettings
}

function OnboardLaVmWithoutReInstall {
    <#
	.SYNOPSIS
	Onboard LA on VM, ReInstall flag not provided.
	#>
    param
    (
        [Parameter(mandatory = $True)]
        [Microsoft.Azure.Commands.Compute.Models.PSVirtualMachine]
        $VMObject,
        [Parameter(mandatory = $True)]
        [hashtable]
        $ExtensionSettings
    )

    $osType = $VMObject.StorageProfile.OsDisk.OsType.ToString()
    $laExtensionConstantProperties = $laExtensionMap[$osType]
    $extensionName = $laDefaultExtensionName
    $extUpgradeSettings = $extensionVmDefaultUpgradeSettings.clone()

    $extension = GetVMExtension -VMObject $VMObject -ExtensionProperties $laExtensionConstantProperties
    $vmlogheader = FormatVmIdentifier -VMObject $VMObject
    # Use supplied name unless already deployed, use same name
    if ($extension) {
        $extensionName = $extension.Name
        RetainExtensionUpgradeSettings -Extension $extension -ExtUpgradeSettings $extUpgradeSettings
        Write-Host "$vmlogheader : Extension $extensionName, type $($laExtensionConstantProperties.Publisher).$($laExtensionConstantProperties.ExtensionType) already installed. Provisioning State : $($extension.ProvisioningState)"
        if ($osType -eq "Linux" -and $extension.PublicSettings) {
            $extensionPublicSettingsJson = $extension.PublicSettings | ConvertFrom-Json 
            if ($extensionPublicSettingsJson.workspaceId -ne $ExtensionSettings.Settings.workspaceId) {
                Write-Host "$vmlogheader : OmsAgentForLinux does not support changing the workspace. Use the -Reinstall flag to make the change."
                return $VMObject
            }
        }
    }

    return SetVMExtension -VMObject $VMObject `
                          -ExtensionName $extensionName `
                          @laExtensionConstantProperties `
                          -ExtensionUpgradeSettings $extUpgradeSettings `
                          -ExtensionSettings $ExtensionSettings
}

function OnboardVmiWithAmaVm {
    <#
	.SYNOPSIS
	Onboard VMI with AMA on VM.
	#>
    param
    (
        [Parameter(mandatory = $True)]
        [Microsoft.Azure.Commands.Compute.Models.PSVirtualMachine]
        $VMObject,
        [Parameter(mandatory = $True)]
        [hashtable]
        $ExtensionSettings
    )

    $VMObject = AssignVmUserManagedIdentity -VMObject $VMObject
    NewDCRAssociationVm -VMObject $VMObject
    return OnboardAmaVm -VMObject $VMObject -ExtensionSettings $ExtensionSettings
}

function OnboardVmiWithAmaVmss {
    <#
	.SYNOPSIS
	Onboard VMI with AMA on VMSS
	#>
    param
    (
        [Parameter(mandatory = $True)]
        [Microsoft.Azure.Commands.Compute.Automation.Models.PSVirtualMachineScaleSet]
        $VMssObject,
        [Parameter(mandatory = $True)]
        [hashtable]
        $ExtensionSettings
    )
            
    $VMssObject = AssignVmssUserManagedIdentity -VMssObject $VMssObject
    NewDCRAssociationVmss -VMssObject $VMssObject
    return OnboardVMssExtension -VMssObject $VMssObject `
                                -ExtensionName $amaDefaultExtensionName `
                                -ExtensionConstantMap $amaExtensionConstantMap `
                                -ExtensionSettings $ExtensionSettings
}

function SetManagedIdentityRoles {
    <#
	.SYNOPSIS
	Set roles to User Assigned Managed Identity.
	#>
    [CmdletBinding(SupportsShouldProcess = $True, ConfirmImpact = 'Medium')]
    param
    (
        [Parameter(Mandatory = $True)]
        [String]
        $ResourceGroupId,
        [Parameter(Mandatory = $True)]
        [object]
        $UserAssignedManagedIdentity,
        [Parameter(Mandatory = $True)]
        [String[]]
        $Roles
    )

    $uamiName = $UserAssignedManagedIdentity.Name
    if (!($PSCmdlet.ShouldProcess($ResourceGroupId, "Assign $Roles to User Assigned Managed Identity $uamiName"))) {
        #-WhatIf skip processing here, return to the caller as we have completed our work.
        if ($WhatIfPreference) {
            return
        }
        throw [CustomerSkip]::new()
    }

    foreach ($role in $Roles) {
        Write-Verbose "Assigning role $role"
        try {
            New-AzRoleAssignment -ObjectId $($UserAssignedManagedIdentity.principalId) `
                                 -RoleDefinitionName $role `
                                 -Scope $ResourceGroupId `
                                 -Confirm:$false
            Write-Verbose "$ResourceGroupId : $role has been successfully assigned to $uamiName"
        } catch {
            $excepMessage = $_.Exception.Message
            if ($excepMessage.Contains('Conflict')) {
                Write-Verbose "$uamiName : Role $role has been assigned already"
            }
            if ($excepMessage.Contains('BadRequest')) {
                throw [FatalException]::new("$uamiName : User Assigned Managed Identity doesn't exist", $_.Exception)
            }
            if ($excepMessage.Contains('NotFound')) {
                throw [ResourceGroupDoesNotExist]::new($($VMObject.ResourceGroupName), $_.Exception)
            }
        }
        
    }
}

function OnboardVMssExtension {
    <#
	.SYNOPSIS
	Install/Update Extension VMSS, handling if already installed
	#>
    #check if this supposed to be all the stack. that is functioing call it as well.
    [CmdletBinding(SupportsShouldProcess = $True, ConfirmImpact = 'Medium')]
    param
    (
        [Parameter(Mandatory = $True)]
        [Microsoft.Azure.Commands.Compute.Automation.Models.PSVirtualMachineScaleSet]
        $VMssObject,
        [Parameter(mandatory = $True)]
        [String]
        $ExtensionName,
        [Parameter(mandatory = $True)]
        [Hashtable]
        $ExtensionConstantMap,
        [Parameter(mandatory = $True)]
        [Hashtable]
        $ExtensionSettings
    )

    $extensionConstantProperties = $ExtensionConstantMap[$VMssObject.VirtualMachineProfile.StorageProfile.OsDisk.OsType.ToString()]
    $extensionType = $extensionConstantProperties.ExtensionType
    $publisher = $extensionConstantProperties.Publisher
    $typeHandlerVersion = $extensionConstantProperties.TypeHandlerVersion
    $extensionUpgradeSettings = @{
        AutoUpgradeMinorVersion = $True
        EnableAutomaticUpgrade = $True 
    }
    $extension = GetVMssExtension -VMssObject $VMssObject -ExtensionType $extensionType -Publisher $publisher
    $vmsslogheader = FormatVmssIdentifier -VMssObject $VMssObject

    if ($extension) {
        if (!($PSCmdlet.ShouldProcess($vmsslogheader, "Update extension $($extension.Name), type = $($publisher).$($extensionType)"))) {
            #-WhatIf skip processing here, return to the caller as we have completed our work.
            if ($WhatIfPreference) {
                return $VMssObject
            }
            throw [CustomerSkip]::new()
        }
        Write-Host "$vmsslogheader : Extension $($extension.Name), type = $($publisher).$($extensionType) already installed."
        #VMSS extension has field "Settings" but Add-AzVmssExtension supports 'Setting'
        if ($ExtensionSettings.ContainsKey("Setting")) {
            $extension.Settings = $ExtensionSettings.Setting
        }
        #VMSS extension has field "ProtectedSettings" but Add-AzVmssExtension supports 'ProtectedSetting'
        if ($ExtensionSettings.ContainsKey("ProtectedSetting")) {
            $extension.ProtectedSettings = $ExtensionSettings.ProtectedSetting
        }
        $extensionUpgradeSettings.GetEnumerator() | ForEach-Object { $extension.($_.Key) = $_.Value }
        $extension.TypeHandlerVersion = $typeHandlerVersion
        return $VMssObject
    }

    if (!($PSCmdlet.ShouldProcess($vmsslogheader, "Install extension $ExtensionName, type = $($publisher).$($extensionType)"))) {
        #-WhatIf skip processing here, return to the caller as we have completed our work.
        if ($WhatIfPreference) {
            return $VMssObject
        }
        throw [CustomerSkip]::new()
    }
    
    $VMssObject = Add-AzVmssExtension -VirtualMachineScaleSet $VMssObject `
                                      -Name $ExtensionName `
                                      -Type $extensionType `
                                      -Publisher $publisher `
                                      -TypeHandlerVersion $typeHandlerVersion `
                                      @extensionUpgradeSettings `
                                      @ExtensionSettings `
                                      -Confirm:$false


    Write-Host "$vmsslogheader : Extension $ExtensionName, type = $($publisher).$($extensionType) added."
    return $VMssObject
}

function SetVMExtension {
    <#
	.SYNOPSIS
	Install/Update VM Extension, handling if already installed
	#>
    [CmdletBinding(SupportsShouldProcess = $True, ConfirmImpact = 'Medium')]
    param
    (
        [Parameter(mandatory = $True)]
        [Microsoft.Azure.Commands.Compute.Models.PSVirtualMachine]
        $VMObject,
        [Parameter(mandatory = $True)]
        [String]
        $ExtensionName,
        [Parameter(mandatory = $True)]
        [String]
        $ExtensionType,
        [Parameter(mandatory = $True)]
        [String]
        $Publisher,
        [Parameter(mandatory = $True)]
        [String]
        $TypeHandlerVersion,
        [Parameter(mandatory = $True)]
        [Hashtable]
        $ExtensionUpgradeSettings,
        [Parameter(mandatory = $True)]
        [Hashtable]
        $ExtensionSettings
    )
    
    $vmlogheader = $(FormatVmIdentifier -VMObject $VMObject)
    
    if (!($PSCmdlet.ShouldProcess($vmlogheader, "Install/Update extension $ExtensionName, type = $($Publisher).$($ExtensionType)"))) {
        #-WhatIf skip processing here, return to the caller as we have completed our work.
        if ($WhatIfPreference) {
            return $VMObject
        }
        throw [CustomerSkip]::new()
    }

    Write-Host "$vmlogheader : Installing/Updating extension $ExtensionName, type = $($Publisher).$($ExtensionType)"
    
    try {
        $result = Set-AzVMExtension -ResourceGroupName $($VMObject.ResourceGroupName) `
                                    -VMName $($VMObject.Name) `
                                    -Name $ExtensionName `
                                    -ExtensionType $ExtensionType `
                                    -Publisher $Publisher `
                                    -TypeHandlerVersion $TypeHandlerVersion `
                                    @ExtensionUpgradeSettings `
                                    @ExtensionSettings -ForceRerun $True `
                                    -Confirm:$false

        if (!$result.IsSuccessStatusCode) {
            throw [VirtualMachineOperationFailed]::new($VMObject, "Failed to update extension. StatusCode = $($result.StatusCode). ReasonPhrase = $($result.ReasonPhrase)")
        }
    
        Write-Host "$vmlogheader : Successfully installed/updated extension $ExtensionName, type = $($Publisher).$($ExtensionType)"
        return $VMObject
    } catch [Microsoft.Azure.Commands.Compute.Common.ComputeCloudException] {
        $errorMessage = ExtractCloudExceptionErrorMessage -ErrorRecord $_
        $errorCode = ExtractExceptionErrorCode -ErrorRecord $_
        #Found by experimentation. 
        if ($errorCode -eq "OperationNotAllowed" -and $errorMessage -eq "Cannot modify extensions in the VM when the VM is not running.") {
            throw [VirtualMachinePoweredDown]::new($VMObject, $_.Exception)
        }
        
        if ($errorCode -eq "ParentResourceNotFound") {
            throw [VirtualMachineDoesNotExist]::new($VMObject, $_.Exception)
        } 
        
        if ($errorCode -eq "ResourceGroupNotFound") {
            throw [ResourceGroupDoesNotExist]::new($VMObject.ResourceGroupName, $_.Exception)       
        } 
        
        if ($errorCode -eq "VMExtensionHandlerNonTransientError") {
            throw [VirtualMachineExtensionError]::new($VMObject, "$($Publisher).$($ExtensionType)", $_.Exception)       
        }

        throw [VirtualMachineUnknownException]::new($VMObject, "Failed to install/update extension $ExtensionName, type = $($Publisher).$($ExtensionType)", $_.Exception)
    }
}

function UpgradeVmssExtensionManualUpdateEnabled {
    <#
	.SYNOPSIS
	Upgrade VMss Extension with manual update.
	#>
    [CmdletBinding(SupportsShouldProcess = $True, ConfirmImpact = 'Medium')]
    param
    (
        [Parameter(mandatory = $True)]
        [Microsoft.Azure.Commands.Compute.Automation.Models.PSVirtualMachineScaleSet]
        $VMssObject,
        [Parameter(mandatory = $True)]
        [ref]
        $InstanceUpgradeFailCounter
    )
    
    $vmssResourceGroupName = $VMssObject.ResourceGroupName
    $vmssName = $VMssObject.Name
    $vmsslogheader = FormatVmssIdentifier -VMssObject $VMssObject
    
    $scaleSetInstances = @()
    try {
        $scaleSetInstances = Get-AzVmssVm -ResourceGroupName $vmssResourceGroupName -VMScaleSetName $vmssName -InstanceView
    } catch [Microsoft.Azure.Commands.Compute.Common.ComputeCloudException] {
        $errorCode = ExtractExceptionErrorCode -ErrorRecord $_
        if ($errorCode -eq "ParentResourceNotFound") {
            throw [VirtualMachineScaleSetDoesNotExist]::new($VMssObject, $_.Exception)
        }
        if ($errorCode -eq "ResourceGroupNotFound") {
            throw [ResourceGroupDoesNotExist]::new($VMssObject.ResourceGroupName, $_.Exception)       
        } 
        
        throw [VirtualMachineScaleSetUnknownException]::new($VMssObject, "Failed to upgrade VMSS", $_.Exception)
    }

    $i = 0
    $instanceCount = $scaleSetInstances.Count
    $unexpectedUpgradeExceptionCounter = 0
    $unexpectedUpgradeExceptionLimit = 5 
    
    Foreach ($scaleSetInstance in $scaleSetInstances) {
        $i++
        $healthstatus = $scaleSetInstance.InstanceView.Statuses.Code

        if (!($healthstatus -contains 'ProvisioningState/succeeded' -and $healthstatus -contains 'PowerState/running')) {
            Write-Host "VMSS instance $scaleSetInstanceName, $i of $instanceCount is not operational. State = $($scaleSetInstance.InstanceView.Statuses.DisplayStatus)"
            Write-Host "Continuing ..."
            $InstanceUpgradeFailCounter.Value += 1
            continue
        }

        $scaleSetInstanceName = $($scaleSetInstance.Name)
        Write-Host "$vmsslogheader : Upgrading $scaleSetInstanceName, $i of $instanceCount"

        if ($scaleSetInstance.LatestModelApplied) {
            Write-Verbose "$vmsslogheader : Latest model already applied for $scaleSetInstanceName, $i of $instanceCount"
            continue
        }
        
        Write-Verbose "$vmsslogheader : Upgrading VMSS instance name $scaleSetInstanceName, $i of $instanceCount"
        try {
            $result = Update-AzVmssInstance -ResourceGroupName $vmssResourceGroupName `
                                            -VMScaleSetName $vmssName `
                                            -InstanceId $scaleSetInstance.InstanceId `
                                            -Confirm:$false
            if ($result.Status -ne "Succeeded") {
                Write-Host "$vmsslogheader : Failed to upgrade VMSS instance name $scaleSetInstanceName, $i of $instanceCount. $($result.Status)"
                $InstanceUpgradeFailCounter.Value += 1
            } else {
                Write-Verbose "$vmsslogheader : Upgrade VMSS instance name $scaleSetInstanceName, $i of $instanceCount"
            }
        } catch [Microsoft.Azure.Commands.Compute.Common.ComputeCloudException] {
            $errorCode = ExtractExceptionErrorCode -ErrorRecord $_
            if ($errorCode -eq "ResourceNotFound") { 
                throw [VirtualMachineScaleSetDoesNotExist]::new($VMssObject, $_.Exception)
            }

            if ($errorCode -eq "ResourceGroupNotFound") {
                throw [ResourceGroupDoesNotExist]::new($VMssObject.ResourceGroupName ,$_.Exception)  
            }

            if ($unexpectedUpgradeExceptionCounter -gt $unexpectedUpgradeExceptionLimit) {
                throw [VirtualMachineScaleSetUnknownException]::new($VMssObject, "More than $unexpectedUpgradeExceptionLimit unexpected exceptions encountered", $_.Exception)
            }

            if ($errorCode -eq "OperationNotAllowed") {
                Write-Host "$vmsslogheader : Failed to locate VMSS instance name $scaleSetInstanceName. Continuing ..."
            } elseif ($errorCode -eq "VMExtensionHandlerNonTransientError") {
                Write-Host "$vmsslogheader : Failed to upgrade extension for VMSS instance name $scaleSetInstanceName, $i of $instanceCount."
                VerboseDisplayException -ErrorRecord $_
                Write-Host "Continuing ..."
            } else {
                Write-Host "$vmsslogheader : Failed to upgrade VMSS instance name $scaleSetInstanceName, $i of $instanceCount. ErrorCode $errorCode." 
                DisplayException -ErrorRecord $_
                Write-Host "Continuing ..."
                $unexpectedUpgradeExceptionCounter += 1
            }
            
            $InstanceUpgradeFailCounter.Value += 1
        }
    }
}

function UpdateVMssExtension {
    <#
	.SYNOPSIS
	Update VMss Extension
	#>
    [CmdletBinding(SupportsShouldProcess = $True, ConfirmImpact = 'Medium')]
    param
    (
        [Parameter(mandatory = $True)]
        [Microsoft.Azure.Commands.Compute.Automation.Models.PSVirtualMachineScaleSet]
        $VMssObject
    )

    $vmsslogheader = FormatVMssIdentifier -VMssObject $VMssObject

    if (!($PSCmdlet.ShouldProcess($vmsslogheader, "Update VMSS"))) {
        #-WhatIf skip processing here, return to the caller as we have completed our work.
        if ($WhatIfPreference) {
            return $VMssObject
        }
        throw [CustomerSkip]::new()
    }

    Write-Host "$vmsslogheader : Updating VMSS"
    try {
        $VMssObject = Update-AzVmss -VMScaleSetName $VMssObject.Name `
                                    -ResourceGroupName $VMssObject.ResourceGroupName `
                                    -VirtualMachineScaleSet $VMssObject `
                                    -Confirm:$false
        if ($VMssObject.ProvisioningState -ne "Succeeded") {
            throw [VirtualMachineScaleSetOperationFailed]::new($VMssObject, "Failed to update VMSS")
        }
        Write-Host "$vmsslogheader : Successfully updated scale set with extension"
        return $VMssObject                           
    } catch [Microsoft.Azure.Commands.Compute.Common.ComputeCloudException] {
        $errorCode = ExtractExceptionErrorCode -ErrorRecord $_
        if ($errorCode -eq "ParentResourceNotFound") {
            throw [VirtualMachineScaleSetDoesNotExist]::new($VMssObject, $_.Exception)
        } 
        
        if ($errorCode -eq "ResourceGroupNotFound") {
            throw [ResourceGroupDoesNotExist]::new($($VMssObject.ResourceGroupName), $_.Exception)       
        }
        
        if ($errorCode -eq "VMExtensionHandlerNonTransientError") {
            throw [VirtualMachineScaleSetExtensionError]::new($VMssObject, $_.Exception)   
        }

        throw [VirtualMachineScaleSetUnknownException]::new($VMssObject, "Failed to update VMSS", $_.Exception)
    }
}

function AssignVmssUserManagedIdentity {
    <#
	.SYNOPSIS
	Checking if User Assigned Managed Identity is already assigned to VMSS, if not assigning it
	#>
    [CmdletBinding(SupportsShouldProcess = $True, ConfirmImpact = 'Medium')]
    param
    (
        [Parameter(Mandatory = $True)]
        [Microsoft.Azure.Commands.Compute.Automation.Models.PSVirtualMachineScaleSet]
        $VMssObject
    )

    $userAssignedManagedIdentityName = $UserAssignedManagedIdentityObject.Name
    $vmsslogheader = FormatVmssIdentifier -VMssObject $VmssObject
    $vmssResourceGroupName = $VMssObject.ResourceGroupName
                                  
    if ($VMssObject.Identity.UserAssignedIdentities.Keys -contains $UserAssignedManagedIdentityObject.Id) {
        Write-Host "$vmsslogheader : User Assigned Managed Identity $userAssignedManagedIdentityName already assigned."
        return $VMssObject
    }

    if (!($PSCmdlet.ShouldProcess($vmsslogheader, "Assign User Assigned Managed Identity $userAssignedManagedIdentityName"))) {
        #-WhatIf skip processing here, return to the caller as we have completed our work.
        if ($WhatIfPreference) {
            return $VMssObject
        }
        throw [CustomerSkip]::new()
    }

    $identityType = if ("$($VMssObject.Identity.Type)".StartsWith("SystemAssigned")) { "SystemAssignedUserAssigned" } else { "UserAssigned" }
    $identityList = [System.Collections.Generic.List[string]]@($UserAssignedManagedIdentityObject.Id)
    if ($VMssObject.Identity.UserAssignedIdentities) {
        $identityList += $VMssObject.Identity.UserAssignedIdentities.Keys
    }

    Write-Host "$vmsslogheader : Assigning User Assigned Managed Identity $userAssignedManagedIdentityName"
    try {
        $VMssObject = Update-AzVmss -VMScaleSetName $VMssObject.Name `
                                -ResourceGroupName  $vmssResourceGroupName `
                                -VirtualMachineScaleSet $VMssObject `
                                -IdentityType $identityType `
                                -IdentityID $identityList `
                                -Confirm:$false
        if ($VMssObject.ProvisioningState -ne "Succeeded") {
            throw [VirtualMachineOperationScaleSetFailed]::new($VMssObject, "Failed to assign User Assigned Managed Identity $userAssignedManagedIdentityName")
        }
        
        Write-Host "$vmsslogheader : Successfully assigned User Assigned Managed Identity $userAssignedManagedIdentityName"
        return $VMssObject
    } catch [Microsoft.Azure.Commands.Compute.Common.ComputeCloudException] {
        $errorCode = ExtractExceptionErrorCode -ErrorRecord $_
        if ($errorCode -eq "FailedIdentityOperation") {
            throw [UserAssignedManagedIdentityDoesNotExist]::new($userAssignedManagedIdentityName, $_.Exception)
        }
        if ($errorCode -eq "ResourceGroupNotFound") {
            throw [ResourceGroupDoesNotExist]::new($vmssResourceGroupName, $_.Exception)       
        } 
        if ($errorCode -eq "InvalidParameter") {
            throw [VirtualMachineScaleSetDoesNotExist]::new($VMssObject, $_.Exception) 
        } 
            
        throw [VirtualMachineScaleSetUnknownException]::new($VMssObject, "Failed to assign User Assigned Managed Identity $userAssignedManagedIdentityName", $_.Exception)
    }
}

function AssignVmUserManagedIdentity {
     <#
	.SYNOPSIS
	Checking if User Assigned Managed Identity is already assigned to VM, if not assigning it
    #>
    [CmdletBinding(SupportsShouldProcess = $True, ConfirmImpact = 'Medium')]
    param
    (
        [Parameter(mandatory = $True)]
        [Microsoft.Azure.Commands.Compute.Models.PSVirtualMachine]
        $VMObject
    )

    $userAssignedManagedIdentityName = $UserAssignedManagedIdentityObject.Name
    $vmlogheader = FormatVmIdentifier -VMObject $VMObject
    $vmResourceGroupName = $VMObject.ResourceGroupName 
    
    if ($VMObject.Identity.UserAssignedIdentities.Keys -contains $UserAssignedManagedIdentityObject.Id) {
        Write-Host "$vmlogheader : User Assigned Managed Identity $userAssignedManagedIdentityName already assigned."
        return $VMObject
    }

    if (!($PSCmdlet.ShouldProcess($vmlogheader, "Assign User Assigned Managed Identity $userAssignedManagedIdentityName"))) {
        #-WhatIf skip processing here, return to the caller as we have completed our work.
        if ($WhatIfPreference) {
            return $VMObject
        } 
        throw [CustomerSkip]::new()
    }

    $identityType = if ("$($VMObject.Identity.Type)".StartsWith("SystemAssigned")) { "SystemAssignedUserAssigned" } else { "UserAssigned" }
    $identityList = [System.Collections.Generic.List[string]]@($UserAssignedManagedIdentityObject.Id)
    if ($VMObject.Identity.UserAssignedIdentities) {
        $identityList += $VMObject.Identity.UserAssignedIdentities.Keys
    }

    Write-Host "$vmlogheader : Assigning User Assigned Managed Identity $userAssignedManagedIdentityName"

    try {
        $result = Update-AzVM -VM $VMObject `
                                -ResourceGroupName $vmResourceGroupName `
                                -IdentityType $identityType `
                                -IdentityID $identityList `
                                -Confirm:$false
    } catch [Microsoft.Azure.Commands.Compute.Common.ComputeCloudException] {
        $errorCode = ExtractExceptionErrorCode -ErrorRecord $_
        if ($errorCode -eq "FailedIdentityOperation") {
            throw [UserAssignedManagedIdentityDoesNotExist]::new($userAssignedManagedIdentityName, $_.Exception)
        }
        if ($errorCode -eq "ResourceGroupNotFound") {
            throw [ResourceGroupDoesNotExist]::new($vmResourceGroupName, $_.Exception)       
        }
        if ($errorCode -eq "InvalidParameter") {
            throw [VirtualMachineDoesNotExist]::new($VMObject, $_.Exception)
        }
        
        throw [VirtualMachineUnknownException]::new($VMObject, "Failed to update VM with $userAssignedManagedIdentityName", $_.Exception)
    }

    if (!($result.IsSuccessStatusCode)) {
        throw [VirtualMachineOperationFailed]::new($VMObject, "Failed to assign User Assigned Managed Identity $userAssignedManagedIdentityName. StatusCode : $($result.StatusCode). ReasonPhrase : $($result.ReasonPhrase)")
    }
    
    Write-Host "$vmlogheader : Successfully assigned User Assigned Managed Identity $userAssignedManagedIdentityName"
    return $VMObject
}

function SetManagedIdentityRolesAma {
    <#
    .SYNOPSIS
    Set Roles to a User Assigned Managed Identity
    #>
    param(
        [Parameter(Mandatory = $True)]
        [String]
        $ResourceGroupName
    )
    
    try { 
        $rgObj = Get-AzResourceGroup -Name $ResourceGroupName
    } catch { 
        $errorCode = ExtractExceptionErrorCode -ErrorRecord $_
        if ($errorCode -eq "ResourceGroupNotFound") {
            throw [FatalException]::new("$ResourceGroupName : Not found.", $_.Exception)
        }
         
        throw [FatalException]::new("Unable to lookup Resource Group.", $_.Exception)
    }

    $roles = @("Virtual Machine Contributor", "Azure Connected Machine Resource Administrator", "Log Analytics Contributor")
    Write-Host "($ResourceGroupName) : Assigning roles"
    SetManagedIdentityRoles -ResourceGroupId $rgObj.ResourceId `
                            -UserAssignedManagedIdentity $UserAssignedManagedIdentityObject `
                            -Roles $roles
}

#
# Main Script
#
#
#
try {
    # To report on overall status
    $onboardingCounters = [OnboardingCounters]::new()
    $unknownExceptionVirtualMachineScaleSetConsequentCounter = 0
    $unknownExceptionVirtualMachineConsequentCounter = 0
    $unknownExceptionTotalCounter = 0
    # First make sure we are authenticed and Select the subscription supplied and input parameters are valid.
    $account =  Get-AzContext
    if ($null -eq $account.Account) {
        Write-Host "Account Context not found, please login"
        Connect-AzAccount -WhatIf:$False -Confirm:$False -subscriptionid $SubscriptionId
    }
    else {
        if ($account.Subscription.Id -eq $SubscriptionId) {
            Write-Verbose "Subscription : $SubscriptionId is already selected."
            $account
        }
        else {
            Write-Host "Current Subscription :"
            $account
            Write-Host "Changing to subscription : $SubscriptionId"
            Select-AzSubscription -WhatIf:$False -Confirm:$False -SubscriptionId $SubscriptionId
        }
    }

    #script block
    Set-Variable -WhatIf:$False -Confirm:$False -Name sb_nop_block_roles -Option Constant -Value { param([String]$rgName)} 
    Set-Variable -WhatIf:$False -Confirm:$False -Name sb_nop_block_upgrade -Option Constant -Value { `
        param([Microsoft.Azure.Commands.Compute.Automation.Models.PSVirtualMachineScaleSet]$vmssObj, [ref]$instanceUpgradeFailCounter)
    }
    Set-Variable -WhatIf:$False -Confirm:$False -Name sb_nop_block_vm -Option Constant -Value { `
        param([Microsoft.Azure.Commands.Compute.Models.PSVirtualMachine]$vmObj) $vmObj
    }
    Set-Variable -WhatIf:$False -Confirm:$False -Name sb_nop_block_vmss -Option Constant -Value { `
        param([Microsoft.Azure.Commands.Compute.Automation.Models.PSVirtualMachineScaleSet]$vmssObj) $vmssObj
    }
    
    $Rghashtable = @{}
    
    if (!$isAma) {
        #Cannot validate Workspace existence with WorkspaceId, WorkspaceKey parameters.
        $local:laSettings = @{"workspaceId" = $WorkspaceId; "stopOnMultipleConnections" = "true"}
        $local:laProtectedSettings = @{"workspaceKey" = $WorkspaceKey}
        Set-Variable -WhatIf:$False -Confirm:$False -Name laExtensionSettingsVm -Option Constant -Value `
        @{
            "Settings" = $local:laSettings
            "ProtectedSettings" = $local:laProtectedSettings
        }
        
        Set-Variable -WhatIf:$False -Confirm:$False -Name laExtensionSettingsVmss -Option Constant -Value `
        @{ 
            "Setting" = $local:laSettings
            "ProtectedSetting" = $local:laProtectedSettings
        }
            
        $local:daSettings = @{"enableAMA" = "false"}
        Set-Variable -WhatIf:$False -Confirm:$False -Name daExtensionSettingsVm -Option Constant -Value `
        @{
            "Settings" = $local:daSettings
        }
        Set-Variable -WhatIf:$False -Confirm:$False -Name daExtensionSettingsVmss -Option Constant -Value `
        @{  
            "Setting" = $local:daSettings
        }
        
        
        if ($ReInstall) {
            Set-Variable -WhatIf:$False -Confirm:$False -Name sb_vm -Option Constant -Value { `
                param([Microsoft.Azure.Commands.Compute.Models.PSVirtualMachine]$vmObj) `
                OnboardLaVmWithReInstall -VMObject $vmObj `
                                         -ExtensionSettings $laExtensionSettingsVm
            }
        } else {
            Set-Variable -WhatIf:$False -Confirm:$False -Name sb_vm -Option Constant -Value { `
                param([Microsoft.Azure.Commands.Compute.Models.PSVirtualMachine]$vmObj) `
                OnboardLaVmWithoutReInstall -VMObject $vmObj `
                                            -ExtensionSettings $laExtensionSettingsVm
            }
        }
        
        Set-Variable -WhatIf:$False -Confirm:$False -Name sb_vmss -Option Constant -Value { `
            param([Microsoft.Azure.Commands.Compute.Automation.Models.PSVirtualMachineScaleSet]$vmssObj) `
            OnboardVMssExtension -VMssObject $vmssObj `
                                 -ExtensionName $laDefaultExtensionName `
                                 -ExtensionConstantMap $laExtensionMap `
                                 -ExtensionSettings $laExtensionSettingsVmss
        }
        
        Set-Variable -WhatIf:$False -Confirm:$False -Name sb_da -Option Constant -Value { `
            param([Microsoft.Azure.Commands.Compute.Models.PSVirtualMachine]$vmObj) `
            OnboardDaVm -VMObject $vmObj -ExtensionSettings $daExtensionSettingsVm
        }

        Set-Variable -WhatIf:$False -Confirm:$False -Name sb_da_vmss -Option Constant -Value { `
            param([Microsoft.Azure.Commands.Compute.Automation.Models.PSVirtualMachineScaleSet]$vmssObj) `
            OnboardVMssExtension -VMssObject $vmssObj `
                                 -ExtensionName $daDefaultExtensionName `
                                 -ExtensionConstantMap $daExtensionConstantsMap `
                                 -ExtensionSettings $daExtensionSettingsVmss
        }

        Set-Variable -WhatIf:$False -Confirm:$False -Name sb_roles -Option Constant -Value $sb_nop_block_roles
    } else {
        
        try {
            Write-Verbose "Validating ($UserAssignedManagedIdentityResourceGroup, $UserAssignedManagedIdentityName)"
            Set-Variable -WhatIf:$False -Confirm:$False -Name UserAssignedManagedIdentityObject -Option Constant -Value `
                            (Get-AzUserAssignedIdentity -Name $UserAssignedManagedIdentityName `
                                                        -ResourceGroupName $UserAssignedManagedIdentityResourceGroup `
                                                        -ErrorAction Stop)
        } catch {
            $errorCode = ExtractExceptionPrefixErrCode -ErrorRecord $_
            if ($errorCode -eq "ResourceNotFound") {
                throw [UserAssignedManagedIdentityDoesNotExist]::new($UserAssignedManagedIdentityName, $_.Exception)
            }
            
            if ($errorCode -eq "ResourceGroupNotFound") {
                throw [UserAssignedManagedIdentityResourceGroupDoesNotExist]::new($UserAssignedManagedIdentityResourceGroup, $_.Exception)
            }

            throw [UserAssignedManagedIdentityUnknownException]::new("($UserAssignedManagedIdentityResourceGroup) $UserAssignedManagedIdentityName : Failed to locate User Assigned Managed Identity.", $_.Exception)
        }
        
        $local:amaSettings = @{
            'authentication' = @{ 
                'managedIdentity' = @{
                    'identifier-name' = 'mi_res_id'
                    'identifier-value' = $($UserAssignedManagedIdentityObject.Id) 
                }
            }
        }
        
        Set-Variable -WhatIf:$False -Confirm:$False -Name amaExtensionSettingsVm -Option Constant -Value `
        @{
            "Settings" = $local:amaSettings
        }

        Set-Variable -WhatIf:$False -Confirm:$False -Name amaExtensionSettingsVmss -Option Constant -Value `
        @{
            "Setting" = $local:amaSettings
        }
        
        Set-Variable -WhatIf:$False -Confirm:$False -Name sb_vm -Option Constant -Value { `
            param([Microsoft.Azure.Commands.Compute.Models.PSVirtualMachine]$vmObj) `
            OnboardVmiWithAmaVm -VMObject $vmObj -ExtensionSettings $amaExtensionSettingsVm
        }
        Set-Variable -WhatIf:$False -Confirm:$False -Name sb_vmss -Option Constant -Value { `
            param([Microsoft.Azure.Commands.Compute.Automation.Models.PSVirtualMachineScaleSet]$vmssObj) `
            OnboardVmiWithAmaVmss -VMssObject $vmssObj -ExtensionSettings $amaExtensionSettingsVmss
        }
        
        if (!$ProcessAndDependencies) {
            Set-Variable -WhatIf:$False -Confirm:$False -Name sb_da -Option Constant -Value $sb_nop_block_vm
            Set-Variable -WhatIf:$False -Confirm:$False -Name sb_da_vmss -Option Constant -Value $sb_nop_block_vmss
        } else {
            $local:daSettings = @{"enableAMA" = "true"}
            Set-Variable -WhatIf:$False -Confirm:$False -Name daExtensionSettingsVm -Option Constant -Value `
            @{
                "Settings" = $local:daSettings
            }
            Set-Variable -WhatIf:$False -Confirm:$False -Name daExtensionSettingsVmss -Option Constant -Value `
            @{  
                "Setting" = $local:daSettings
            }
            
            Set-Variable -WhatIf:$False -Confirm:$False -Name sb_da -Option Constant -Value { `
                param([Microsoft.Azure.Commands.Compute.Models.PSVirtualMachine]$vmObj) `
                OnboardDaVm -VMObject $vmObj -ExtensionSettings $daExtensionSettingsVm
            }

            Set-Variable -WhatIf:$False -Confirm:$False -Name sb_da_vmss -Option Constant -Value { `
                param([Microsoft.Azure.Commands.Compute.Automation.Models.PSVirtualMachineScaleSet]$vmssObj) `
                OnboardVMssExtension -VMssObject $vmssObj `
                                     -ExtensionName $daDefaultExtensionName `
                                     -ExtensionConstantMap $daExtensionConstantsMap `
                                     -ExtensionSettings $daExtensionSettingsVmss
            }
        }
    
        Set-Variable -WhatIf:$False -Confirm:$False -Name sb_roles -Option Constant -Value { `
            param([String]$rgName) SetManagedIdentityRolesAma -ResourceGroupName $rgName
        }
    }

    if ($TriggerVmssManualVMUpdate) {
        Set-Variable -WhatIf:$False -Confirm:$False -Name sb_upgrade -Option Constant -Value { `
            param([Microsoft.Azure.Commands.Compute.Automation.Models.PSVirtualMachineScaleSet]$vmssObj, [ref]$instanceUpgradeFailCounter) `
            UpgradeVmssExtensionManualUpdateEnabled -VMssObject $vmssObj -InstanceUpgradeFailCounter $instanceUpgradeFailCounter
        }
    } else {
        Set-Variable -WhatIf:$False -Confirm:$False -Name sb_upgrade -Option Constant -Value $sb_nop_block_upgrade
    }

    if ($PolicyAssignmentName) {
        #this section is only for VMs
        Write-Host "Looking up Virtual Machines in policy assignment $PolicyAssignmentName"

        $policyAssignmentNameResources = @{}
        Get-AzPolicyState `
            -Filter "PolicyAssignmentName eq '$PolicyAssignmentName' and ResourceType eq 'Microsoft.Compute/virtualMachines'" `
            | ForEach-Object {
                $policyAssignmentNameResources.Add($_.ResourceId, $True)
              }

        try {
            #Virtual Machines part of a VMSS will be skipped.
            Get-AzVM -ResourceGroupName $ResourceGroup -Name $Name `
                | Where-Object {!($_.VirtualMachineScaleSet) -and $policyAssignmentNameResources.ContainsKey($_.Id)} `
                | ForEach-Object {
                    $onboardingCounters.Total +=1 ;
                    PopulateRgHashTableVm -Rghashtable $Rghashtable -VMObject $_
                }
        } catch {
            $errorCode = ExtractExceptionErrorCode -ErrorRecord $_
            if (!($errorCode -eq "ResourceGroupNotFound" -or $errorCode -eq "ResourceNotFound")) {
                throw [FatalException]::new("Unable to lookup VMs", $_.Exception)
            }

            #quietly do nothing.
        } 
    } else {
        Write-Host ""
        Write-Host "Getting list of VMs or VM Scale Sets matching specified criteria."
        #Skipping heath status check as API output throttling noticed at scale and wild-cards are not accepted with Get-AzVM -Status. 
        try {
            Get-AzVM -ResourceGroupName $ResourceGroup -Name $Name `
                | Where-Object {!($_.VirtualMachineScaleSet)} `
                | ForEach-Object { 
                    $onboardingCounters.Total +=1 ; 
                    PopulateRgHashTableVm -Rghashtable $Rghashtable -VMObject $_
                }
        } catch {
            $errorCode = ExtractExceptionErrorCode -ErrorRecord $_
            if (!($errorCode -eq "ResourceGroupNotFound" -or $errorCode -eq "ResourceNotFound")) {
                throw [FatalException]::new("Unable to lookup VMs", $_.Exception)
            }

            #quietly do nothing.
        }

        try {
            #VMI does not support VMSS with flexible orchestration.
            Get-AzVmss -ResourceGroupName $ResourceGroup -Name $Name `
                | Where-Object {$_.OrchestrationMode -ne 'Flexible'} `
                | ForEach-Object {
                    $onboardingCounters.Total +=1 ; 
                    PopulateRgHashTableVmss -RgHashTable $Rghashtable -VMssObject $_
                }
        } catch {
            $errorCode = ExtractExceptionErrorCode -ErrorRecord $_
            if (!($errorCode -eq "ResourceGroupNotFound" -or $errorCode -eq "ResourceNotFound")) {
                throw [FatalException]::new("Unable to lookup VMSS", $_.Exception)
            }

            #quietly do nothing.
        } 
    }

    $rgList = $Rghashtable.GetEnumerator() | Sort-Object -Property Key
    Write-Host "VM's and VMSS matching selection criteria :"
    $ManualUpgrade = 0
    Foreach ($entry in $rgList) {
        $rg = $entry.Key
        $rgTableObj = $entry.Value
        $vmList = $rgTableObj.VirtualMachineList
        $vmssList = $rgTableObj.VirtualMachineScaleSetList
        Write-Host ""
        Write-Host "ResourceGroup : $rg"


        if ($vmList.Count -gt 0) {
            $vmList = Sort-Object -Property Name -InputObject $vmList
            $vmList | ForEach-Object { Write-Host "  $($_.Name)" }
            $rgTableObj.VirtualMachineList = $vmList
        }
        
        if ($vmssList.Count -gt 0) {
            $vmssList = Sort-Object -Property Name -InputObject $vmssList
            $vmssList | ForEach-Object { Write-Host "  $($_.Name) - Upgrade mode $($_.UpgradePolicy.Mode)"; `
                                         if ($_.UpgradePolicy.Mode -eq "Manual") {$ManualUpgrade+=1}
                                       }
            $rgTableObj.VirtualMachineScaleSetList = $vmssList
        }
    }

    if ($ManualUpgrade -gt 0 -and !$TriggerVmssManualVMUpdate) {
        Write-Host "Found $ManualUpgrade VMSS with upgrade mode 'Manual'."
        Write-Host "'-TriggerVmssManualVMUpdate' was not provided. Upgrade will not be performed." 
    }

    Write-Host ""

    # Validate customer wants to continue
    if ($Approve -or $WhatIfPreference -or $PSCmdlet.ShouldContinue("Continue?", "")) {
        Write-Host ""
    } else {
        Write-Host "You selected No - exiting"
        $onboardingCounters.Total = 0
        exit 1
    }
    
    ForEach ($entry in $rgList) {
        $rg = $entry.Key
        $rgTableObj = $entry.Value
        try {
            &$sb_roles -rgName $rg
            
            foreach ($vm in $rgTableObj.VirtualMachineList) {
                try {
                    Write-Host ""
                    #This is on best-effort basis. State can change later.
                    if (!(IsVmAndGuestAgentUpAndHealthy -VMObject $vm)) {
                        Write-Host "Continuing to the next VM ..."
                        $onboardingCounters.Skipped +=1
                        continue
                    }
                    $vm = &$sb_vm -vmObj $vm
                    $vm = &$sb_da -vmObj $vm
                    Write-Host "$(FormatVmIdentifier -VMObject $vm) : Successfully onboarded VM insights"
                    $onboardingCounters.Succeeded +=1
                    $unknownExceptionVirtualMachineConsequentCounter = 0
                } catch [VirtualMachineUnknownException] {
                    if ($unknownExceptionVirtualMachineConsequentCounter -gt $unknownExceptionVirtualMachineConsequentCounterLimit) {
                        throw [FatalException]::new("More than $unknownExceptionVirtualMachineConsequentCounterLimit unexpected exceptions encountered consequtively", $_.Exception)
                    }
                    if ($unknownExceptionTotalCounter -gt $unknownExceptionTotalCounterLimit) {
                        throw [FatalException]::new("More than $unknownExceptionTotalCounterLimit unexpected exceptions encountered", $_.Exception)
                    }
                    Write-Host "Unexpected VM Exception :"
                    $unknownExceptionTotalCounter+=1
                    $unknownExceptionVirtualMachineConsequentCounter+=1
                    DisplayException -ErrorRecord $_
                    Write-Host "Continuing to the next VM ..."
                } catch [VirtualMachineException] {
                    Write-Host "VM Exception :"
                    VerboseDisplayException -ErrorRecord $_
                    Write-Host "Continuing to the next VM ..."
                } catch [CustomerSkip] {
                    Write-Host "Onboarding operation aborted"
                    Write-Host "Continuing to the next VM ..."
                    $onboardingCounters.Skipped +=1
                }
            }

            foreach ($vmss in $rgTableObj.VirtualMachineScaleSetList) {
                try {
                    Write-Host ""
                    $vmsslogheader = FormatVmssIdentifier -VMssObject $vmss
                    $vmss = &$sb_vmss -vmssObj $vmss
                    $vmss = &$sb_da_vmss -vmssObj $vmss
                    $vmss = UpdateVMssExtension -VMssObject $vmss
                    $instanceUpgradeFailCounter = 0
                    if ($vmss.UpgradePolicy.Mode -eq 'Manual') {
                        &$sb_upgrade -vmssObj $vmss -InstanceUpgradeFailCounter ([ref]$instanceUpgradeFailCounter)
                    }
                    $onboardingCounters.VMSSInstanceUpgradeFailure += $instanceUpgradeFailCounter
                    if ($instanceUpgradeFailCounter -eq 0) {
                        Write-Host "$vmsslogheader : Successfully onboarded VM insights"
                        $onboardingCounters.Succeeded +=1
                    }
                    $unknownExceptionVirtualMachineScaleSetConsequentCounter = 0
                } catch [VirtualMachineScaleSetUnknownException] {
                    if ($unknownExceptionVirtualMachineScaleSetConsequentCounter -gt $unknownExceptionVirtualMachineScaleSetConsequentCounterLimit) {
                        throw [FatalException]::new("More than $unknownExceptionVirtualMachineScaleSetConsequentCounterLimit unexpected exceptions encountered consequtively", $_.Exception)
                    }
                    if ($unknownExceptionTotalCounter -gt $unknownExceptionTotalCounterLimit) {
                        throw [FatalException]::new("More than $unknownExceptionTotalCounterLimit unexpected exceptions encountered", $_.Exception)
                    }
                    $unknownExceptionTotalCounter+=1
                    $unknownExceptionVirtualMachineScaleSetConsequentCounter+=1
                    Write-Host "Unexpected VMSS Exception :"
                    DisplayException -ErrorRecord $_
                    Write-Host "Continuing to the next VMSS ..."
                } catch [VirtualMachineScaleSetException] {
                    Write-Host "VMSS Exception :"
                    VerboseDisplayException -ErrorRecord $_
                    Write-Host "Continuing to the next VMSS ..."
                } catch [CustomerSkip] {
                    Write-Host "Onboarding operation aborted"
                    Write-Host "Continuing to the next VMSS ..."
                    $onboardingCounters.Skipped +=1
                }
            }
        } catch [ResourceGroupDoesNotExist] {
            Write-Host "Resource Group Exception :"
            VerboseDisplayException -ErrorRecord $_
            Write-Host "Continuing to the next Resource Group ..."
        } catch [CustomerSkip] {
            Write-Host "Onboarding operation aborted"
            $onboardingCounters.Skipped += $rgTableObj.VirtualMachineList.Count + $rgTableObj.VirtualMachineScaleSetList.Count
        }
    }
}
catch [UserAssignedManagedIdentityUnknownException] {
    Write-Host "Fatal Exception :"
    DisplayException -ErrorRecord $_
    Write-Host "Exiting ..."
    exit 2
}
# Customer actionable exceptions
catch [FatalException] {
    Write-Host "Fatal Exception :"
    VerboseDisplayException -ErrorRecord $_
    Write-Host "Exiting ..."
    exit 3
}
catch {
    Write-Host "Unexpected Fatal Exception :"
    DisplayException -ErrorRecord $_
    Write-Host "Exiting ..."
    exit 4
}
finally {
    PrintSummaryMessage  $onboardingCounters
}