I'm trying to set up a Windows domain in virtual machines (VMs) instead inside of an OpenStack deployment. I've configured one of the VMs to be the domain controller (including DNS server), running Windows 2012 server. I'm trying to figure out how to configure things so that the DNS server gets updated entries as new Windows VMs come up and join the domain.

From my understanding, the way this typically works is that the domain controller acts as both a DNS server and a DHCP server. When a new machine comes up and requests an IP via DHCP, as part of this process the DHCP client requests a DNS dynamic update which is handled by the DHCP server (James Hebden provided a link to this in the comment).

However, since these are virtual machines running inside of an OpenStack deployment, dnsmasq is acting as the DHCP server. I think this is the reason that the DNS server on the domain controller isn't updated with new entries, even when these instances are joined to the domain.

Is there any way to configure dnsmasq and/or the domain controller such that the DNS server gets automatically updated with the new instances? Or is that simply not possible unless I use the domain controller as the DHCP server?

If possible, I'd prefer to keep the DHCP server managed by OpenStack (i.e. dnsmasq), since I need OpenStack to manage the IPs for some desired functionality (floating IPs).

  • Can you elaborate on the DHCP setup? Normally the DHCP server would be keeping the DNS records up to date in this configuration. Take a look here for an overview of the DNS/DHCP interaction: technet.microsoft.com/en-us/library/cc787034(v=ws.10).aspx – James Hebden Jun 8 '13 at 0:06
  • I'm going to rewrite the question entirely to clear things up. – Lorin Hochstein Jun 8 '13 at 3:49
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    You don't need to use Windows DHCP to keep the DNS entries up to date. Something else is going on here. – Michael Hampton Jun 8 '13 at 3:59
  • @JamesHebden that's not the default behavior – MDMarra Jun 8 '13 at 4:01
  • @MichaelHampton Perhaps I should ask a simpler question: How do the DNS entries on the domain controller get added for new machines that come up? Will it happen when the machine joins the domain? – Lorin Hochstein Jun 8 '13 at 4:02

By default, Active Directory clients will update their own records using secure dynamic DNS updates. Once they are joined to the domain, they should immediately and automatically create this record in your ADI DNS zones.

It has nothing to do with DHCP in a default configuration. You can use DHCP proxy updates, but this is not recommended in most deployments and needs extra configuration. If you were using this configuration, you'd know it.

See this article for more info: http://technet.microsoft.com/en-us/library/cc771255.aspx

| improve this answer | |
  • I rolled back my question to the original one I asked, where I'm getting name resolution errors even though the machine has joined the domain. – Lorin Hochstein Jun 8 '13 at 4:07
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    sigh if you have more than one question, ask more than one question. Don't use edits bounce back and forth after one of them has been answered. – MDMarra Jun 8 '13 at 4:10
  • Reverted, will ask a new question. – Lorin Hochstein Jun 9 '13 at 2:53

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