2-RemoveAvailabilityGroupReplica.ps1

<#
.EXAMPLE
    This example shows how to ensure that the Availability Group Replica 'SQL2' does not exist in the Availability Group 'TestAG'.
#>

$ConfigurationData = @{
    AllNodes = @(
        @{
            NodeName                    = '*'
            SQLInstanceName             = 'MSSQLSERVER'
            AvailabilityGroupName       = 'TestAG'

            <#
                NOTE! THIS IS NOT RECOMMENDED IN PRODUCTION.
                This is added so that AppVeyor automatic tests can pass, otherwise
                the tests will fail on passwords being in plain text and not being
                encrypted. Because it is not possible to have a certificate in
                AppVeyor to encrypt the passwords we need to add the parameter
                'PSDscAllowPlainTextPassword'.
                NOTE! THIS IS NOT RECOMMENDED IN PRODUCTION.
            #>
            PSDscAllowPlainTextPassword = $true
        },

        @{
            NodeName = 'SQL1'
            Role     = 'PrimaryReplica'
        },

        @{
            NodeName = 'SQL2'
            Role     = 'SecondaryReplica'
        }
    )
}

Configuration Example
{
    param(
        [Parameter(Mandatory = $true)]
        [System.Management.Automation.PSCredential]
        $SqlAdministratorCredential
    )

    Import-DscResource -ModuleName SqlServerDsc

    Node $AllNodes.NodeName {
        # Adding the required service account to allow the cluster to log into SQL
        SqlServerLogin AddNTServiceClusSvc
        {
            Ensure               = 'Present'
            Name                 = 'NT SERVICE\ClusSvc'
            LoginType            = 'WindowsUser'
            ServerName           = $Node.NodeName
            InstanceName         = $Node.SQLInstanceName
            PsDscRunAsCredential = $SqlAdministratorCredential
        }

        # Add the required permissions to the cluster service login
        SqlServerPermission AddNTServiceClusSvcPermissions
        {
            DependsOn            = '[SqlServerLogin]AddNTServiceClusSvc'
            Ensure               = 'Present'
            ServerName           = $Node.NodeName
            InstanceName         = $Node.SqlInstanceName
            Principal            = 'NT SERVICE\ClusSvc'
            Permission           = 'AlterAnyAvailabilityGroup', 'ViewServerState'
            PsDscRunAsCredential = $SqlAdministratorCredential
        }

        # Create a DatabaseMirroring endpoint
        SqlServerEndpoint HADREndpoint
        {
            EndPointName         = 'HADR'
            Ensure               = 'Present'
            Port                 = 5022
            ServerName           = $Node.NodeName
            InstanceName         = $Node.SQLInstanceName
            PsDscRunAsCredential = $SqlAdministratorCredential
        }

        if ( $Node.Role -eq 'PrimaryReplica' )
        {
            # Create the availability group on the instance tagged as the primary replica
            SqlAG AddTestAG
            {
                Ensure               = 'Present'
                Name                 = $Node.AvailabilityGroupName
                InstanceName         = $Node.SQLInstanceName
                ServerName           = $Node.NodeName
                DependsOn            = '[SqlServerEndpoint]HADREndpoint', '[SqlServerPermission]AddNTServiceClusSvcPermissions'
                PsDscRunAsCredential = $SqlAdministratorCredential
            }
        }

        if ( $Node.Role -eq 'SecondaryReplica' )
        {
            # Add the availability group replica to the availability group
            SqlAGReplica AddReplica
            {
                Ensure                     = 'Absent'
                Name                       = $Node.NodeName
                AvailabilityGroupName      = $Node.AvailabilityGroupName
                ServerName                 = $Node.NodeName
                InstanceName               = $Node.SQLInstanceName
                PrimaryReplicaServerName   = ( $AllNodes | Where-Object { $_.Role -eq 'PrimaryReplica' } ).NodeName
                PrimaryReplicaInstanceName = ( $AllNodes | Where-Object { $_.Role -eq 'PrimaryReplica' } ).SQLInstanceName
            }
        }
    }
}