functions/Enable-DbaAgHadr.ps1

#ValidationTags#Messaging,FlowControl,Pipeline,CodeStyle#
function Enable-DbaAgHadr {
<#
    .SYNOPSIS
        Enables the Hadr service setting on the specified SQL Server.
 
    .DESCRIPTION
        In order to build an AG a cluster has to be built and then the Hadr enabled for the SQL Server
        service. This function enables that feature for the SQL Server service.
 
    .PARAMETER SqlInstance
        The target SQL Server instance or instances.
 
    .PARAMETER Credential
        Credential object used to connect to the Windows server itself as a different user
 
    .PARAMETER WhatIf
        Shows what would happen if the command were to run. No actions are actually performed.
 
    .PARAMETER Confirm
        Prompts you for confirmation before executing any changing operations within the command.
 
    .PARAMETER Force
        Will restart SQL Server and SQL Server Agent service to apply the change.
 
    .PARAMETER EnableException
        By default, when something goes wrong we try to catch it, interpret it and give you a friendly warning message.
        This avoids overwhelming you with "sea of red" exceptions, but is inconvenient because it basically disables advanced scripting.
        Using this switch turns this "nice by default" feature off and enables you to catch exceptions with your own try/catch.
 
    .NOTES
        Tags: Hadr, HA, AG, AvailabilityGroup
        Author: Shawn Melton (@wsmelton), http://wsmelton.github.io
 
        Website: https://dbatools.io
        Copyright: (c) 2018 by dbatools, licensed under MIT
        License: MIT https://opensource.org/licenses/MIT
 
    .LINK
        https://dbatools.io/Enable-DbaAgHadr
 
    .EXAMPLE
        PS C:\> Enable-DbaAgHadr -SqlInstance sql2016 -Force
 
        Sets Hadr service to enabled for the instance sql2016, and restart the service to apply the change.
 
    .EXAMPLE
        PS C:\> Enable-DbaAgHadr -SqlInstance sql2012\dev1 -Force
 
        Sets Hadr service to disabled for the instance dev1 on sq2012, and restart the service to apply the change.
 
#>

    [CmdletBinding(SupportsShouldProcess = $true, ConfirmImpact = "High")]
    param (
        [parameter(Mandatory, ValueFromPipeline)]
        [Alias("ServerInstance", "SqlServer")]
        [DbaInstanceParameter[]]$SqlInstance,
        [PSCredential]$Credential,
        [switch]$Force,
        [Alias('Silent')]
        [switch]$EnableException
    )
    begin {
        function GetDbaAgHadr {
    <#
        .SYNOPSIS
            Gets the Hadr service setting on the specified SQL Server instance.
 
        .DESCRIPTION
            Gets the Hadr setting, from the service level, and returns true or false for the specified SQL Server instance.
 
        .PARAMETER SqlInstance
            The target SQL Server instance or instances.
 
        .PARAMETER Credential
            Credential object used to connect to the Windows server itself as a different user
 
        .PARAMETER EnableException
            By default, when something goes wrong we try to catch it, interpret it and give you a friendly warning message.
            This avoids overwhelming you with "sea of red" exceptions, but is inconvenient because it basically disables advanced scripting.
            Using this switch turns this "nice by default" feature off and enables you to catch exceptions with your own try/catch.
 
        .NOTES
            Tags: Hadr, AG, AvailabilityGroup
            Author: Shawn Melton (@wsmelton | http://wsmelton.github.io)
 
            Website: https://dbatools.io
            Copyright: (c) 2018 by dbatools, licensed under MIT
            License: MIT https://opensource.org/licenses/MIT
 
        .LINK
            https://dbatools.io/GetDbaAgHadr
 
        .EXAMPLE
            GetDbaAgHadr -SqlInstance sql2016
 
            Returns a status of the Hadr setting for sql2016 SQL Server instance.
    #>

            [CmdletBinding()]
            param (
                [parameter(Mandatory, ValueFromPipeline)]
                [Alias("ServerInstance", "SqlServer")]
                [DbaInstanceParameter[]]$SqlInstance,
                [PSCredential]$Credential,
                [Alias('Silent')]
                [switch]$EnableException
            )
            process {
                foreach ($instance in $SqlInstance) {

                    try {
                        $computer = $computerName = $instance.ComputerName
                        $instanceName = $instance.InstanceName
                        $currentState = Invoke-ManagedComputerCommand -ComputerName $computerName -ScriptBlock { $wmi.Services[$args[0]] | Select-Object IsHadrEnabled } -ArgumentList $instanceName -Credential $Credential
                    }
                    catch {
                        Stop-Function -Message "Failure connecting to $computer" -Category ConnectionError -ErrorRecord $_ -Target $instance
                        return
                    }

                    if ($null -eq $currentState.IsHadrEnabled) {
                        $isenabled = $false
                    }
                    else {
                        $isenabled = $currentState.IsHadrEnabled
                    }
                    [PSCustomObject]@{
                        ComputerName     = $computer
                        InstanceName     = $instanceName
                        SqlInstance      = $instance.FullName
                        IsHadrEnabled    = $isenabled
                    }
                }
            }
        }
    }
    process {
        foreach ($instance in $SqlInstance) {
            $computer = $computerFullName = $instance.ComputerName
            $instanceName = $instance.InstanceName
            if (-not (Test-ElevationRequirement -ComputerName $instance)) {
                return
            }
            $noChange = $false

            switch ($instance.InstanceName) {
                'MSSQLSERVER' { $agentName = 'SQLSERVERAGENT' }
                default { $agentName = "SQLAgent`$$instanceName" }
            }

            try {
                Write-Message -Level Verbose -Message "Checking current Hadr setting for $computer"
                $currentState = GetDbaAgHadr -SqlInstance $instance -Credential $Credential
            }
            catch {
                Stop-Function -Message "Failure to pull current state of Hadr setting on $computer" -Category ConnectionError -ErrorRecord $_ -Target $instance -Continue
            }
            $isHadrEnabled = $currentState.IsHadrEnabled
            Write-Message -Level InternalComment -Message "$instance Hadr current value: $isHadrEnabled"

            # hadr results from sql wmi can be iffy, skip the check
            <#
            if ($isHadrEnabled) {
                Write-Message -Level Warning -Message "Hadr is already enabled for instance: $($instance.FullName)"
                $noChange = $true
                continue
            }
            #>


            $scriptblock = {
                $instance = $args[0]
                $sqlService = $wmi.Services | Where-Object DisplayName -eq "SQL Server ($instance)"
                $sqlService.ChangeHadrServiceSetting(1)
            }

            if ($noChange -eq $false) {
                if ($PSCmdlet.ShouldProcess($instance, "Changing Hadr from $isHadrEnabled to 1 for $instance")) {
                    try {
                        Invoke-ManagedComputerCommand -ComputerName $computerFullName -Credential $Credential -ScriptBlock $scriptblock -ArgumentList $instancename
                    }
                    catch {
                        Stop-Function -Continue -Message "Failure on $($instance.FullName) | This may be because AlwaysOn Availability Groups feature requires the x86(non-WOW) or x64 Enterprise Edition of SQL Server 2012 (or later version) running on Windows Server 2008 (or later version) with WSFC hotfix KB 2494036 installed."
                    }
                }
            }

            if (Test-Bound -ParameterName Force) {
                if ($PSCmdlet.ShouldProcess($instance, "Force provided, restarting Engine and Agent service for $instance on $computerFullName")) {
                    try {
                        $null = Stop-DbaService -ComputerName $computerFullName -InstanceName $instanceName -Type Agent, Engine
                        $null = Start-DbaService -ComputerName $computerFullName -InstanceName $instanceName -Type Agent, Engine
                    }
                    catch {
                        Stop-Function -Message "Issue restarting $instance" -Target $instance -Continue
                    }
                }
            }
            $newState = GetDbaAgHadr -SqlInstance $instance -Credential $Credential

            if (Test-Bound -Not -ParameterName Force) {
                Write-Message -Level Warning -Message "You must restart the SQL Server for it to take effect."
            }

            [PSCustomObject]@{
                ComputerName    = $newState.ComputerName
                InstanceName    = $newState.InstanceName
                SqlInstance     = $newState.SqlInstance
                IsHadrEnabled   = $true
            }
        }
    }
}