ESX 4 VM Hardware Upgrades loses DNS Registrations for VMs

[davparker]

Environment:

ESX recently upgraded to 4.0

Upgraded VMTools (Tools don't always upgrade via Update Manager, some have to be manually upgraded)

Upgrade VM Hardware using Update Manager on Windows 2003 Guests

Last step requires 3 reboots.

1 - To install VM Hardware

2 - After first login, drivers are updates requiring reboot

3 - DNS Registrations are lost/revoked after step 2, third reboot reregisters DNS.

The install docs only speak about 1 reboot to install hardware. It's very troubling that after the second reboot, dns registrations are lost, cannot ping servers by hostname as they no longer exist. After rebooting, the dns records are registered again. So far this has been the case on every Windows 2003 server we've upgraded. Needless to say, this was incredibly disruptive to our organization as it took awhile to figure out the HA upgrade was triggering servers to unregister the host entries from Active Directory.

[AndreTheGiant]

There is a similar thread (on other network settings):

Andre

[RParker]

Upgrade VM Hardware using Update Manager on Windows 2003 Guests

Yes this is ALSO normal procedure. ANY Time you change network settings, drivers, name whatever these settings will change. That is a side effect of how Windows works.

DNS stands for DYNAMIC Naming Service, which means the updates occur dynamically, and since you CHANGE the NIC / Driver in a VM it CHANGES the properties of the NIC.

So when the machine reboots it has to reestablish connections with DHCP/DNS. The problem is it's NOT losing the DNS, it takes time to replicate the changes. That's what is happening, it's not an error its a Windows function / behavior, completely normally (maybe not what makes sense, but it is normal).

I suspect that initially you may not be able to ping, because after you CHANGE network it has to get a NEW DHCP address (even if the MAC is the same, the Network does not know it at the time). There is going to be a few minutes before you can register on the DNS server again.

By the time you reboot it registers, but you aren't giving enough time for this to occur naturally.

[davparker]

The dns records don't get re-registered after the 2nd reboot. A flush of the dns cache verifies this. You either have to "ipconfig /registerdns", manually add the record, or reboot the server again after the second reboot. In either case, the bare minimum number of reboots to update the VM Hardware is two. This is not reflected in the documentation. That, and the issues with dns registration aren't mentioned. That's why I'm bringing it up. Maybe other's will be spared the agony.

[davparker]

FYI,

DNS stands for Domain Naming Service

DDNS is Dynamic DNS

What I can't figure out is why our statically assigned IP addresses in Active Directory are unregistering during the hardware upgrade. I realize Active Directory utilizes DDNS. Maybe when the guys setup the servers, they didn't actually manually enter the record, but it registered upon joining the domain? Then unregistered when the new nic was installed?

[RParker]

, the bare minimum number of reboots to update the VM Hardware is two. This is not reflected in the documentation.

OK, I understand, but the real issue here is Windows is doing it NOT Vm Ware hardware upgrade, the hardware upgrade is an OPTION and as a result of that action, causes the NIC to reset, which is part of Windows. So if you KNOW it's an issue, perhaps you should arrest hardware upgrades until a solution can be found, because we use DHCP / DNS and I have upgrade the hardware to Version 7 and we don't have this problem, on Windows 2000.20003, 20008. I have tried it several times not a problem.

So it must be something on your WINS database (archive time out, DNS synch, etc..) something isn't right.

[RParker]

DNS stands for Domain Naming Service

OK, sorry Domain, but it's done dynamically... and technically its DOMAIN NAMING SYSTEM (according to Microsoft)

What I can't figure out is why our statically assigned IP addresses in Active Directory are unregistering during the hardware upgrade.

Not sure of this either considering its a new A record which is usually a manual process, but if you do /ipconfig /registerdns that should work, not sure why it requires a reboot.It still takes a few minutes (given the WINS server activity and the time to sync) for changes to be reflected. I still say a reboot is NOT required, it's just time. So something else is wrong with your configuration why a reboot does something that an ipconfig update does NOT, something isn't right there either. Unless you are doing it in the wrong order.

It should be update tools FIRST, THEN power off the VM. THEN upgrade hardware, THEN let the VM detect new hardware, THEN a reboot (all of which are normal Windows plug and pray functions) which is probably WHY the second reboot is required, the hardware hasn't been fully implemented, a la the message "Newer devices have been detected, but may NOT be ready until you reboot". Windows gives you this warning EVERY major hardware change.

This is all a Windows DHCP / WINS / DDNS / IP Configuration issue, and it's a result OF the hardware upgrade, but it's not being CAUSED by the hardware upgrade, the two have no correlation.

[davparker]

the ipconfig /registerdns does not require a reboot. Its just the 3rd reboot is a way to solve it. I'm saying that the install docs should warn of additional reboots while installing hardware. 2 at a minimum instead of 1. I'm leaning towards the loss of the dns record is due to the fact the record wasn't manually entered to start with, but it was registered when the server joined the domain. Even though it was statically assigned to the server, it was dynamically registered with dns. I'm still seeing the loss of dns entries while upgrading hardware. The only machines that haven't are 2 Windows 2003 domain controllers. I know those addresses were statically entered into dns.

[craiggunson]

Slightly different solution that I feel will work better at scale, or those companies who can't wait longer than a reboot.

1. Upgrade tools at your leisure.

2. Deny your DHCP account access to the DNS record of the VM's your upgrading. This is the account used for DDNS updates.

3. Upgrade hard-ware at your leisure.

DNS record is never lost, and remains intact. No loss or change to DNS record, No waiting, No re-registering.