How to edit a server in a DNS Cluster in whm?

What is a DNS Cluster?

A DNS Cluster is a group of nameservers that share DNS records with each other. This allows you to physically separate the nameservers that handle DNS requests from your web servers, improving reliability and redundancy. In WHM, you can manage cluster members and change their roles (how they participate in DNS synchronization) at any time.

Understanding DNS Server Roles

• Standalone — The server does not synchronize DNS records with any other server. It only serves its own DNS data.
• Master — The server pushes DNS records to other servers in the cluster. Typically your main cPanel server is set as Master.
• Slave — The server receives DNS record updates from the Master server(s). Commonly used for dedicated DNS-only servers.
• Synchronize — The server both pushes and receives DNS records. Both directions of synchronization are active.
• Write-only — The server pushes DNS records to other members but does not receive any updates from them.

Steps to Edit a Server in a DNS Cluster

1. Log in to WHM as the root user.
2. Navigate to Home » Clusters » DNS Cluster.
3. Under the Manage DNS Cluster section, locate the server you want to edit in the list of cluster members.
4. Find the DNS Role dropdown menu next to the server entry.
5. Click the dropdown and select the new role you want to assign to this server.
6. Click the save icon (the floppy disk icon) to the right of the server entry to apply your changes.
7. Repeat for any additional servers you want to modify.

Important Notes

• Make sure DNS clustering is enabled globally by clicking Enable DNS clustering at the top of the DNS Cluster page.
• Changes to server roles take effect immediately. DNS records will begin synchronizing according to the new role configuration.
• If a cluster member becomes unresponsive, WHM can automatically disable it based on the Failure threshold for cluster members setting.
• All servers in the DNS cluster must run PowerDNS if any domains using DNSSEC exist in the cluster.
• The Setup Remote Access Key must be properly configured on both the local and remote servers for cluster communication to work.
• Resellers can manage DNS clusters if they have the DNS Clustering Account Creation Limit ACL privilege.

Troubleshooting

• Changes are not saving: Ensure you clicked the save icon (not just selected the dropdown). Refresh the page to verify.
• DNS records are not syncing: Verify the remote access key is valid on both servers. Check that the server IP address is correct and that port 2087 (WHM) is accessible between the servers.
• Cluster member shows as disabled: The member may have exceeded the failure threshold. Check server connectivity and re-enable it if needed.
• Cannot find a server in the list: The server may not have been added to the cluster yet. Click Add a new server to the cluster to add it first.

For official documentation, see the cPanel DNS Cluster guide and the Guide to DNS Cluster Configurations.