DNS Cluster "Could not communicate with remote API server"

thowden

Active Member
May 17, 2013
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Hi All

I have a DNS Cluster of 3 DNS Only servers with 6 Web servers using Write-Only connections to each of the DNS Only servers.

I have had an ongoing issue when trying to manually 'Synchronize DNS Records' to the cluster and errors showing with one or more of the DNS servers. this seems to occur with all / any of the web servers but without any discernible pattern. Like it could be any of the webservers showing any of the name servers as 'unknown', but never all of the name servers, there is always at least 1 name server showing ok.

1595371161952.png
If I select another page in the WHM console and return then the error message is gone and all 3 of the DNS servers are listed as connected and ok.

I am just not clear if this should be expected when selecting the manual Synchronize DNS Records from the WHM menu or if I actually have an API or Token issue ?

Thoughts ?

Thanks.
 
Last edited:

cPAdminsMichael

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Dec 19, 2016
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Hmm... sounds odd. Are you running NAT or your servers on different VLANs?
 

cPAdminsMichael

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Hm - I don't have a good explanation to your issue. It's a bit odd that it's random - else I would say that it's network or firewall related..
I suggest you open a support ticket (If you haven't already done).
 

andrew.n

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As far as I know the APIs uses the cPanel default ports to communicate (2083,2086 etc...). Are you able to telnet to these ports from one server to another? Do you have cpHulk or hosts access restriction in place? These could explain the connection issues you see.
 

cPanelLauren

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Can you please open a ticket using the link in my signature? Once open please reply with the Ticket ID here so that we can update this thread with the resolution once the ticket is resolved.


Thanks!
 

thowden

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May 17, 2013
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As far as I know the APIs uses the cPanel default ports to communicate (2083,2086 etc...). Are you able to telnet to these ports from one server to another? Do you have cpHulk or hosts access restriction in place? These could explain the connection issues you see.
Hi Andrew

Thanks for the input. I'd expect that if it were a port or firewall issue then it would be either open or closed and not intermittent. I can trigger the sync, get the error, check the dns cluster page to see an outage, screenshot it, refresh it, and have all servers connected. It looks more like a timing issue.
 

blue928

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Feb 7, 2021
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I'm having this issue as well. I followed the instructions on setting up a separate DNS Only server and added it to the cluster. Everything works fine, and I got a greenlight for the first server just like the OP did in the above screenshot. I used Terraform to setup my first server, and I used the same Terraform plan to spin up an exact replica of the server, and I then configured its hostname and IP address.


When I added the server I got an intermediate page that said that everything was working fine - that synchronization was good and reverse trust was good. Then when I got back to the clusters page, I get the same error for the second server.

I rebuilt the server manually just in case my Terraform plan did something wonky. No go - no matter what I do, this always displays that error. I can telnet to and from each server I can access all recommended ports per the documentation.

Just like the OP the only difference between these two servers is that they are in different geographically distributed datacenters. I have not tested if that could be the case, but then again, that would defeat the purpose of having reliable DNS servers if they were in the same data center.

I see that a support ticket was submitted from above. Was this issue resolved? Can you post the results or how to resolve if so?

Thanks!
 

andrewmoras

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Feb 6, 2021
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I'm having this issue as well. I followed the instructions on setting up a separate DNS Only server and added it to the cluster. Everything works fine, and I got a greenlight for the first server just like the OP did in the above screenshot.
I'm seeing the same problem on two nameservers that recently got upgraded to cPanel v94 DNS ONLY. Whenever I "edit" one server I get:

DNS Cluster Management
The Trust Relationship has been established.
The remote server, ns1.domain.com, is running WHM version: 10.0.0
The new role for IP ADDRESS is sync. Return to Cluster Status


but when I go back to cluster status I see: "Could not communicate with remote API server."

Anyone else having the same issue?
 

cPRex

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Oct 19, 2014
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@blue928 - in the ticket that was opened, we discovered intermittent network issues, although that customer did not write back saying what the official resolution was.

It sounds like you may be experiencing the following interface error, which you can ignore: cPanel

Can you check that and see if that is the case? The same would apply for @andrewmoras
 
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andrewmoras

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@blue928 - in the ticket that was opened, we discovered intermittent network issues, although that customer did not write back saying what the official resolution was.

It sounds like you may be experiencing the following interface error, which you can ignore: cPanel

Can you check that and see if that is the case? The same would apply for @andrewmoras
It seems like you're right, as always @cPRex. Looking forward to see this resolved :)

Thanks,
Andrew
 
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