@james411 - Can't help with why it's happening, perhaps a bug or corruption/issue with your configuration files.

However, you can check whether the ESXi host is able to resolve via both DNS servers by logging into the ESXi host via SSH, and running the following commands:

• nslookup <SampleTarget-IP> <DNS-ServerA-IP>
• nslookup <SampleTarget-IP> <DNS-ServerB-IP>

The output will confirm if both DNS servers are resolving correctly 

You could ssh to the vCenter appliance and run the following tool as root. Choose option 4 to edit the DNS settings for the appliance. I've had to use this tool to set some networking configuration when doing so from the DCUI of the appliance complained about IPv6 settings. Perhaps it will help you with your DNS settings issue.

SSH to the vCenter as root, type "shell" to get to the bash shell, then run the following cli tool.

/opt/vmware/share/vami/vami_config_net

Check the "/etc/resolv.conf" file and see if both the server are configured as nameserver.

If both the entries are there, you are good to go.

Regards,

Sachchidanand

@swint OK, I am able to use the vami_config_net tool to make changes. After I input the new DNS settings via this tool, it says "DNS server settings updated" I can see the changes in the DCUI, in the VAMI on port 5480, and in /etc/resolv.conf

Also, I've confirmed every change I make to the DNS settings in the DCUI throws the error about SETTING DNS FAILED. However, even though I get this message I check the /etc/resolv.conf and the VAMI website and see the changes are indeed there. @Sachchidanand 

@markey165 I tried doing nslookup from the console and it resolved OK.

So, no one else gets this error? You can all change your DNS settings just fine from the DCUI?

Hi @james411 

It seems to be a cosmatic issue as checked I am also getting the same error/warning, but dns is successfully changed.

If you see the configure management network is showing confirm and dns is also changed, but that specific line may be due to cosmatic or wrong mapping of alert in the code or anything else.

attaching screenshot for reference.

Regards,

Sachchidanand

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So, no one else gets this error? You can all change your DNS settings just fine from the DCUI?

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@james411 - I just updated my lab host from 8.0 Update 1A to Update 1C to test this.

I changed the DNS IPs (both Primary and Secondary) via the DCUI both before and after patching, then restarted the management network when prompted in each case, and didn't see the issue in either build.

In my case i had a clean install of Update 1A and patched directly to 1C, so i wonder if something is getting carried through from another build in your case?

@markey165 Thanks for trying and letting me know. This is quite odd. This is a brand new deployment so there is no previous build that would carryover. That is what really bugs me: when you have a fresh install and you still see unclean errors like this.

@Sachchidanand That is exactly the error I am getting. Thanks for checking. I guess I will move forward with deployment anyway. It doesn't seem to be affecting anything.

Hey James @james411 

Out of interest, how did you install ESXi 8.01C as a new build? 

In my VMware Portal, the latest ISO is 8.0U1A (see screenshot). The only way (i can see) to get 8.01C is by patching 8.01A as per my test above. Am i missing something? 

@markey165 But the vCenter Server appliance is 8.0U1c no? You have it in your downloads there. VMware-VCSA-all-8.0.1-22088981.iso is the file I downloaded.

Ahh sorry, when you said DCUI, i immediately defaulted to thinking we were talking about ESXi, but re-reading I see you put VCSA in your first post, my bad 

Ok I have vCenter 8.0 Update 1C too. I've done some testing, and I can indeed replicate the error, but what i'm seeing is intermittent. At first I thought the error was only occurring when I set an invalid DNS server, as it didn't error when i set the correct DNS server. This led me to conclude the procedure is doing a test on port 53 and/or an ICMP ping, but as i tested further, it then errored on the correct DNS server, even though it didn't error on the same IP address on a previous attempt. So its completely random.

This looks like a bug to me! Might be worth escalating to support, as it seems this can be easily replicated