cPanel DNS Clustering migration from old cPanel DNS only server (Centos 5, 6) to new cPanel DNS only server, can be done effortlessly if we can follow the below steps.
Firstly, we need to check and understand the current setup of DNS clustering in production before migration. In this case, I have taken the Write-only cPanel DNS clustering migration setup. Once this is done we need to set up new servers as same to replace the old cluster servers.
One main concern with the migration is, we would not want to update the already existing accesshash key on the child servers live. The accesshash authentication in cPanel was deprecated after cPanel version 64. We would also not recommend it on the new servers but if you have more than 30 web servers, it would be a complex step to update the new key on all child servers after migration.
We can alternatively follow these steps involved in cPanel DNS Clustering Migration to migrate the existing old ns server in the cluster with a new one without changing the accesshash key:
In new ns cluster server
- Use API command to generate accesshash via CLI.
- Once generated, copy the existing key from the old server and replace it on the new server.
- Allow the accesshash option in the new server and restart the cPanel service otherwise we will get authentication errors:
- Transfer the /var/named contents from the old cluster server to the new cluster server.
- Perform IP address switch on the new server so it replaces the old server IP address.
- Use the below command to sync the DNS zone from the web servers to the cluster server (Only if required)
- /scripts/dnscluster syncall –full