15.4 Migrating DNS to Another Domain Controller

In a typical DSfW deployment, any domain controller can be configured as a DNS server. If the domain controller serving as primary DNS server does not function due to a hardware or software fault, the other domain controllers need at least one DNS server to keep the domain services intact.

IMPORTANT:The DNS migration can happen even when the source DNS server is down. If the DNS server is down, make sure that any of the additional domain controllers in the forest have the replica of the Tree Root partition. This is necessary to perform Step 2.

When the first domain controller goes down, make sure that the configuration partition and schema partition replica is there on at least one domain controller in the domain. This is required to keep the functioning of DSfW intact.

To migrate the DNS server from the first domain controller, from the additional domain controller execute the following steps:

  1. Using the oescredstore utility, set the credentials on the additional domain controller with the following command.

    oescredstore -s -n dns-ldap -u <username> -p <password>

    To retrieve the common proxy user DN, use the following command:

    /opt/novell/proxymgmt/bin/cp_retrieve_proxy_cred username 

    To retrieve the common proxy user password, use the following command:

    /opt/novell/proxymgmt/bin/cp_retrieve_proxy_cred password 
  2. Using Java Management Console, execute the following steps:

    1. Create a DNS server object. For more information, see Creating a DNS Server Object in the OES 2018 SP3: DNS/DHCP Services for Linux Administration Guide.

      While creating the DNS server object you must specify the NCP server name of the additional domain controller, hostname and the domain name for the server object.

    2. Select the DNS zones in Java Management Console.

      Associate the zone with the DNS server. For details on associating zone with a DNS server, see Zone Managementin the OES 2018 SP3: DNS/DHCP Services for Linux Administration Guide

  3. Restart novell-named on the additional domain controller using the following command:

    rcnovell-named restart

After migrating the DNS server to the destination domain controller, the DNS entry referencing the first domain controller is still retained in the cache for some time. This does not affect the functionality in any way as when a name resolution request is issued, it gets resolved by the DNS server on the other domain controller, if the first domain controller has not responded.

IMPORTANT:If you have changed any DNS records or the configuration file, the changes are effected after the dynamic reconfiguration interval of DNS. The default value of this interval is 15 minutes. If the changes are not done, we recommend you to restart the DNS server using the rcnovell-named restart command.