(WHM >> Home >> Clusters >> DNS Cluster)
A DNS cluster is a group of nameservers that share records, which allows you to physically separate nameservers that handle the DNS requests from your web servers. This interface allows you to configure a DNS cluster and add servers to an existing DNS cluster.
For more information about the types of DNS cluster configuration and why you may wish to use a DNS cluster, read our Guide to DNS Cluster Configurations documentation.
DNS cluster requirements
To configure your DNS cluster, you must meet the following minimum requirements:
- Clusters must include at least two servers.
- You must have at least one web server with cPanel & WHM installed. A DNS cluster that includes multiple cPanel DNSONLY™ servers and cPanel & WHM servers is also acceptable.
- All machines in the DNS cluster must have cPanel & WHM or cPanel DNSONLY version 11 or higher installed. Some features may not work with older versions of cPanel & WHM.
- WHM's DNS Cluster feature only provides redundancy for DNS. It does not add Apache or any other services to a DNS cluster configuration.
- If you set a server in a DNS cluster to the write-only role, WHM will not check whether a DNS zone exists before you create an account. Because of this, it is possible to create the same domain name on two or more of these servers. If this occurs, the servers compete for updates to that domain.
- cPanel DNSONLY software allows you to run a dedicated physical nameserver. It is essentially the "bare-bones" version of cPanel & WHM, which only replicates DNS zones to your other servers. Only install cPanel DNSONLY on nameservers that have no previous content on them. You can download the cPanel DNSONLY software for free.
- All servers in the DNS cluster must run PowerDNS if domains that use DNSSEC exist in that cluster.
- DNSSEC may cause slow response times for backups, transfers and restores, and dnsadmin actions. This is because DNSSEC increases the processor load on these features. If more than 10,000 domains exist in your DNS cluster, we recommend that you not use DNSSEC with DNS clustering.
To modify DNS cluster settings, select whether to manage your DNS clusters as the
root user or as a reseller from the Manging DNS Cluster as menu.
- Users must possess the DNS Clustering Account Creation Limit (ACL) privilege to view the DNS Clustering section of this interface.
- Users who possess the All ACL privilege cannot add their own custom DNS servers to a cluster.
- For more information about these ACLs, read our Edit Reseller Nameservers and Privileges documentation.
Modify cluster status
To enable or disable DNS clustering in WHM, perform the following steps:
- Select the desired option under the Global DNS Cluster Options heading:
- Click Enable DNS clustering to enable DNS clusters.
- Click Disable DNS clustering to disable DNS clusters.
- Click Change. A confirmation message will appear.
- Click Return to Cluster Status.
After you enable the DNS Cluster feature, specify which servers you wish to include in the DNS cluster.
- You must sync each webserver to its DNS servers.
- You do not need to link dedicated DNS servers to each other, or link dedicated web servers to each other.
Global Cluster Options
The Failure threshold for cluster members setting allows you to specify the number of
dnsadmin commands that may fail before WHM disables an unresponsive DNS cluster member.
- We recommend that you disable unresponsive DNS cluster members in order to improve the performance of your server.
- You must enable DNS clustering in order to view the Global Cluster Options section of this interface.
To configure the Failure threshold for cluster members setting, perform the following steps:
- Select an option from the Global Cluster Options section:
Select 10 (Default) to use the default option, which allows cluster members to fail up to ten
We recommend that you use this option.
Select the second option to enter a custom failure threshold.
If server downtimes or network interruptions are common in your hosting environment, we recommend that you increase the failure number count so that the system does not mark certain cluster members as offline. This may also increase server and network load because the system may repeatedly send some DNS requests.
- Select Keep all cluster members online at all times if you wish to keep all of the servers in your DNS cluster continuously online, regardless of the number of failed
If you wish for WHM to notify you when it disables an unresponsive member in your DNS cluster, select Receive a notification when WHM disables an unresponsive cluster member.
You must manually reenable a disabled cluster member.
- Click Change. A confirmation message will display.
- Click Return to Cluster Status.
If a cluster member in the sync role is offline for an extended period of time, resynchronize the other server's zones. This ensures that the cluster member is up-to-date.
Unique DNS Clustering
This option only appears if you manage your DNS cluster as a reseller user.
By default, WHM uses the DNS servers that reside in the
root user or
root-enabled reseller's cluster. To add a different DNS server to the cluster, enable this option.
- To enable this option, click Enable unique DNS clustering for accounts owned by username.
- To enable this option, click Disable unique DNS clustering for accounts owned by username.
- username represents the reseller user.
- Resellers can only change a DNS server's role to Synchronize or Write-only if the
rootuser adds that server to their DNS Cluster.
Servers in your DNS cluster
This section allows you to view, add, and delete servers from your DNS cluster.
The Servers in your DNS cluster table displays the following information about each server in your DNS cluster:
|Hostname||The server's hostname.|
|IP address||The server's IP address.|
|Username||The WHM username that you used when you configured this server in the DNS cluster. Typically, this is either |
|Type||The type of server: cPanel, SoftLayer, or VPS.NET.|
The version of cPanel & WHM that the server currently runs, and an icon that indicates the server's status.
The server's nameserver software.
The server's DNS role. You can choose from the following options:
You can use the menu in this column to change a server's DNS role.
|Actions||You can use the icons in this column to modify a DNS cluster server, update your server to use PowerDNS, or to delete a server from the DNS cluster.|
Add a new server to the cluster
To add a cPanel & WHM or cPanel DNSONLY server to the DNS cluster, perform the following steps:
Select the server type from the Backend Type menu.
To enable DNS clustering with SoftLayer or VPS.NET, you must first obtain an API username and key from VPS.net or SoftLayer. Then, choose SoftLayer or VPS.NET from the Type menu.
- Click Configure. The cPanel DNS Remote Configuration interface will appear.
- Enter the hostname or IP address of the nameserver that you wish to link in the Remote cPanel & WHM DNS host text box.
- Enter the WHM username for the nameserver in the Remote server username text box.
Enter the nameserver's API token hash or remote access key in the Remote server access hash text box.
Enter an API token hash that you saved on your workstation or create a new API token in WHM's Manage API Tokens interface (WHM >> Home >> Development >> Manage API Tokens).
Make certain that after you create an API token, you save the token hash to a safe location on your workstation so that you can use it with other features. The API Tokens table in WHM's Manage API Tokens interface (WHM >> Home >> Development >> Manage API Tokens) only displays the API tokens' names, rather than the tokens' hashes.
You can find the server's remote access key in WHM's Remote Access Key interface (WHM >> Home >> Clusters >> Remote Access Key).
Note:We deprecated WHM's Remote Access Key feature in cPanel & WHM version 64. We strongly recommend that you use API tokens instead.
Select Setup Reverse Trust Relationship for WHM to automatically configure the DNS cluster on the remote server.
- If you select this option, you will not need to log in to WHM's DNS Cluster interface on the remote server. However, you may do so if you wish to modify the remote server's DNS cluster configuration.
- This option automatically sets the remote server's DNS role to Standalone.
- Select Synchronize Zones Immediately if you want to synchronize the new server with the other nameservers in your cluster.
- Select Debug mode if you want WHM to record DNS clustering transactions in the
Select an option from the DNS Role menu to specify the server's DNS role.
Click Submit to save your settings. When you return to the DNS Cluster interface, the remote server will appear in the Servers in your DNS Cluster table.
Use WHM's Synchronize DNS Records interface (WHM >> Home >> DNS Functions >> Synchronize DNS Records) to manually synchronize the new DNS server with the DNS cluster.
We recommend that you do not set up the nameserver to synchronize data to a web server, because this creates extraneous zones on the webserver. This means that you do not need to log in to WHM on the nameserver and set the web server's DNS role to Synchronize changes.
Test the clustered server
To confirm that the new server exists in the cluster, perform the following steps:
- Log in to your server via SSH.
Run the following command, where
example.comrepresents the server name and
iprepresents the server's IP address:
Delete a server from a DNS cluster
- You must delete a server from a DNS zone before you add a replacement server to the DNS cluster. You cannot have two servers with the same hostname in a DNS cluster.
- If you remove a server from a DNS cluster, the records will no longer synchronize with the other servers in the DNS cluster. The records on the deleted server will also no longer exist on the servers that remain in the DNS cluster.
To remove a cPanel & WHM or cPanel DNSONLY server from a DNS cluster, perform the following steps:
- Log in to the server that you wish to remove from the DNS cluster.
- Navigate to the DNS Cluster interface.
- In the Modify Cluster Status text box, select Disable DNS Clustering.
- Click Change.
- Click Return to Cluster Status.
- Log in to the servers that remain in the cluster.
- Navigate to the DNS Cluster interface (WHM >> Home >> Clusters >> DNS Cluster).
- Locate the server that you wish to delete.
- Click the x icon ( ) under the Actions heading.
When you return to the DNS Cluster interface, the server will no longer appear in the list of servers in the DNS cluster.
Edit a server in a DNS Cluster
You can change a server's DNS role or edit the server's configuration settings at any time.
To edit a server's DNS role, perform the following steps:
- Locate the server that you wish to edit.
- In the DNS Role menu, select a new role for the server.
- Click the save icon ( ) to save your changes.
To edit a server's configuration settings, perform the following steps:
- Locate the server you wish to edit.
- Click the edit icon ( ) under the Actions heading. The cPanel DNS Remote Configuration interface will appear.
- After you make your changes to the server's settings, click Submit.