Activating Windows 8 and Windows Server 2012 on existing AD environment

As we putting new Windows 8 and Windows Server 2012 into existing AD environment, there are 2 things that need to be done. First, if you're still using Windows Server 2008 as KMS host, download and install the update 2757817. Otherwise, you'll see the following error when you activate KMS with the new key:

Error: 0xC004F050 The Software Licensing Service reported that the product key is invalid

Next, upgrade the existing key on the KMS host by running:

1. "slmgr /upk" to uninstall existing key, 
2. "slmgr /ipk xxxxx-xxxxx-xxxxx-xxxxx-xxxxx" to install new KMS key and;
3. "slmgr /ato" to activate the new key.
4. "slmgr /dlv" to verify the key has been successfully upgraded to support the new Windows 8. You should see "VOLUME_KMS_2012_C_channel" on the description.

For detailed step-by-step, check out this blog post.