DNS Clustering

DNS clustering enables you to synchronize DNS records across multiple OpenPanel servers, providing redundancy and scalability for your DNS infrastructure.

All servers involved in the cluster must be running BIND9 - either installed by OpenPanel or as a standalone service or container.

Share DNS Across Multiple OpenPanel Servers​

The simplest way to build a redundant DNS cluster is to run OpenPanel on two or more servers, each managing DNS zones and nameservers in sync. No extra configuration is needed beyond what's described below.

Step 1: Allow connections between the servers​

Suppose you have two servers:

• Server #1 IP: MASTER_IP
• Server #2 IP: SLAVE_IP

You need to allow connection between the servers, on MASTER_IP whitelist the SLAVE_IP and on SLAVE_IP whitelist the MASTER_IP:

• on master: csf -a SLAVE_IP
• on slave: csf -a MASTER_IP

Step 2: Prepare Slave Server​

On MASTER server get the secret token from rndc.key file: cat /etc/bind/rndc.key

On SLAVE:

• edit /root/docker-compose.yml and add - "953:953/tcp" under ports for bind9 service.
• edit /etc/bind/named.conf.options and add allow-new-zones yes; inside options block, and append at the end of the file:

  controls {
      inet 0.0.0.0 port 953 allow { MASTER_IP_HERE; } keys { "rndc-key"; };
  };
  
• restart service with: docker exec openpanel_dns rndc reconfig | docker compose up -d bind9

Test connection from MASTER_IP with:

docker exec openpanel_dns rndc -s SLAVE_IP -k rndc-key status

Step 3: Create Nameservers in Your DNS Zone​

Using the domain yourdomain.com as an example, define two nameservers:

• dns1.yourdomain.com → points to Server #1 IP (A record)
• dns2.yourdomain.com → points to Server #2 IP (A record)

Add these A records in your domain's DNS provider for yourdomain.com.

Step 4: Register Nameservers in OpenPanel​

On master server, open the OpenAdmin panel:

• Navigate to Settings > OpenPanel > Nameservers
• Add both dns1.yourdomain.com and dns2.yourdomain.com

Step 5: Enable DNS Clustering​

On master server:

• Go to OpenAdmin > Domains > DNS Cluster
• Click Enable DNS Clustering

• Click Add Server and enter the IP of the slave server, then Add

Test Your Cluster​

Add a new domain on either server via a OpenPanel user account.

Then verify the DNS zone is synchronized on both servers using the dig command:

dig A +short yourdomain.com @185.241.214.214
dig A +short yourdomain.com @95.217.216.36

Replace yourdomain.com with the domain you added.

If both servers return the correct IP, your DNS clustering setup is working!