You dont need to install anything in order to have the KMS service installed on s2k8 and/or s2k8r2 Just type you KMS key into slmgr slmgr -ipk xxxxx-xxxxx-xxxxx-xxxxx-xxxxx -ato It will automatically create the SRV record in DNS and everything Just dont forget to create a rule to allow TCP traffic in port 1688 in that server Anyway you can start the workstations rollout because you will have a 30 day grace period, but the KMS server implementation takes only a couple of minutes