[PowerShell Utils] Automatically Change DNS and then Join Domain

I would like to start a series of blog posts sharing PowerShell scripts to speed up our solution operations.

Today, I am going to share a script file that can select a network adapter, changes its DNS address, then join the server to the domain you specify.

Background

===============

In my environment, I have 15 Windows hosts. I need to configure them from the OS installation to configure fail over cluster and then create and run VMs on them. Without scripting, manually complete related tasks would be very bored and easy to make mistakes. I started using PowerShell and it really helped ease the pain.

Now, let's take a look at the first script that I loved using.

What can this one do

===============

For Cisco C240 servers in Durham lab, we have to use KVM Console to configure initial IP address. Then we will be able to remote to the windows hosts to operate. We want to run PowerShell remotely on all 15 hosts. But without joined to AD, remotely run powershell commands are not possible. This script will help you automatically join a host to domain. No more remote desktop, click here, click there, set this, set that, and then restart server for 15 times!

Logic Intro

===============

First, output the current server's FQDN.

Then, compare the server's domain with your domain name. If they are not the same, the script will select a network adapter which IP address starts with the address you specify.

Then, change this adapter's DNS to point to your domain controller.

Then, join this server to the domain, and automatically restart the host.

Script is here

===============

PowerShell

#

#Set your variables here.

#

$yourDomainName = "midrange.sio"

$yourNetworkInitial = "10.110.70."

$yourDomainControllerIP = "10.110.70.96"

$yourDomainUserName = "Administrator"

$yourDomainUserPassword = "Password01!"


#

#Functions defined here.

#

function OutputAllNetAdaptersInfo ()

{

    foreach($adapter in (get-netadapter | ? {$_.status -eq "up"}))

    {

        $fields= [PSCustomObject]@{

            Ip= ($adapter | Get-NetIPConfiguration).IPv4Address.IPAddress;

            Name= $adapter.Name;

            Description=  $adapter.InterfaceDescription;

        }

        $fields | format-table

    }

}

function FindTargetedNetAdapter($IPInitial)

{

    foreach($adapter in (get-netadapter | ? {$_.status -eq "up"}))

    {

        $fields= [PSCustomObject]@{

            Ip= ($adapter | Get-NetIPConfiguration).IPv4Address.IPAddress;

            Name= $adapter.Name;

            Description=  $adapter.InterfaceDescription;

        }

        if($fields.Ip.StartsWith($IPInitial))

        {

            return $adapter

        }      

    }

    return null;

}


#

#Operation starts here

#

$FQDN = (Get-WmiObject win32_computersystem).DNSHostName+"."+(Get-WmiObject win32_computersystem).Domain

Write-Host "Server name is $FQDN."

if(!(Get-WmiObject win32_computersystem).Domain.ToString().compareTo($yourDomainName))

{

    Write-Host "Server $FQDN is already joined domain $yourDomainName"

}

else

{

    OutputAllNetAdaptersInfo;

    $Tgtadapter = FindTargetedNetAdapter($yourNetworkInitial);

    if($Tgtadapter)

    {

        $Tgtadapter | Set-DnsClientServerAddress -ServerAddresses $yourDomainControllerIP

        $domain = $yourDomainName

        $password = $yourDomainUserPassword | ConvertTo-SecureString -asPlainText -Force

        $username = "$domain\$yourDomainUserName"

        $credential = New-Object System.Management.Automation.PSCredential($username,$password)

        Add-Computer -DomainName $domain -Credential $credential

        Restart-Computer

    }

    Write-Host "No appropriate network adapter found to be used to join domain."

}