Network Location Cannot Be Found (Joining AD Domain)

 

Problem: Network Location Cannot Be Found

When attempting to join the domain the following message appears:

network_domain_join_error1

When this occurs you cannot browse to the UNC path of the domain controller and cannot reach SYSVOL

Solution: Add Client For Microsoft Networks

Browse to control panel and click network and sharing center (or run ncpa.cpl)

Right click your network adapter and go to properties

Ensure that the Client for Microsoft Network is enabled and installed, if it is unchecked tick the checkbox, if it is not present choose install then select client and choose client for Microsoft networks.

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Hyper-V Paused Critical

As many of you reading my blog have realized I am a huge proponent of datacenter virtualization. So here we are with a nicely virtualized Hyper-V failover cluster, we’ve got excellent guest to host density and everything is going well….until it isn’t. I was taking some time off when I received a call in the middle of the night that one of my customer’s entire infrastructure was down. Upon logging in it was apparent something was quite wrong, the failover cluster had failed convergence and the local Hyper-V MMC showed that most over 75% of the VMs were in a paused critical state (see the screenshot below as an example that was reproduced in a lab).

 

pausedcritical

As it turns out one of the cluster shared volumes had reached a point where > 200MB was remaining on the volume. Hyper-V will begin writing to the event log when the volume drops below 2GB with an event log entry for each VM. Once the space drops below 200MB all VMs on that volume will enter a paused critical state. This only applies to thin provisioned disks however at the time of writing this there is a bug that this will occur even with thick provisioned disks. The fun part in my scenario was that both domain controllers were residing on this volume. To remedy the issue I was able to forcibly power-off the domain controllers from their paused state and storage migrate them to another cluster volume. Upon bringing them back up cluster convergence was able to be restored and everything was up and running again. The other thing of note is that the clocks were all paused during this time resulting in major time drift that had to be manually reconciled.

 

Lessons Learned

  • ALWAYS ensure your storage admin has monitoring on the SAN to send alerts when the LUNs reach a critical threshold and warn before that at a lower threshold
  • If you have multiple LUNs keep your Domain Controllers spread across them

Installing Domain Controllers Via Powershell

Anyone who has ever been an AD admin has gone through the fun song and dance of standing up a new domain controller. As an avid user of PowerShell I wanted to provide a quick easy way to standup a new forest and secondary DC without “clicking it to death” rather simply using a couple of quick easy PowerShell statements.

Standing Up First DC (New Forest)
If you are adding a DC to an existing Forest you can skip this section

  • Complete pre-reqs of setting static IP, changing hostname’s etc, then run PowerShell as admin and run the following:
  • Install-WindowsFeature AD-Domain-Services
  • Once the installation has completed the binaries are installed, however the forest has not been created yet. To create a forest run the following cmdlets:

Install-ADDSForest -DomainName example.local -ForestMode <Win2003|Win2008|Win2008R2|Win2012|Win2012R2>

Adding an Additional Domain Controller

  • Complete pre-reqs of setting static IP, changing hostname’s etc, then run PowerShell as admin and run the following:

Install-WindowsFeature AD-Domain-Services

  • Once the binaries install you can promote the DC to an existing domain using the following PowerShell cmdlets:

Install-ADDSDomainController -DomainName example.local -InstallDns -Credential (Get-Credential domainadministrator)

  • Provide a safemode password as prompted

 

Thanks for reading, I look forward to our next post.