Rolling Conversion from DNS to GNS Cluster Name Resolution

You can convert Oracle Grid Infrastructure cluster networks using DNS for name resolution to cluster networks using Grid Naming Service (GNS) obtaining name resolution through GNS.

Use the following procedure to convert from a standard DNS name resolution network to a GNS name resolution network, with no downtime:

See Also:

Oracle Grid Infrastructure Installation Guide for your platform to complete preinstallation steps for configuring GNS

  1. Log in as the Grid user (grid), and use the following Cluster Verification Utility to check the status for moving the cluster to GNS, where nodelist is a comma-delimited list of cluster member nodes:
    $ cluvfy stage –pre crsinst –n nodelist
  2. As the Grid user, check the integrity of the GNS configuration using the following commands, where domain is the domain delegated to GNS for resolution, and gns_vip is the GNS VIP:
    $ cluvfy comp gns -precrsinst -domain domain -vip gns_vip
  3. Log in as root, and use the following SRVCTL command to configure the GNS resource, where domain_name is the domain that your network administrator has configured your DNS to delegate for resolution to GNS, and ip_address is the IP address on which GNS listens for DNS requests:
    # srvctl add gns -domain domain_name -vip ip_address
  4. Use the following command to start GNS:
    # srvctl start gns

    GNS starts and registers VIP and SCAN names.

  5. As root, use the following command to change the network CRS resource to support a mixed mode of static and DHCP network addresses:
    # srvctl modify network -nettype MIXED

    The necessary VIP addresses are obtained from the DHCP server, and brought up.

  6. As the Grid user, enter the following command to ensure that Oracle Clusterware is using the new GNS, dynamic addresses, and listener end points:
    cluvfy stage -post crsinst -n all
  7. After the verification succeeds, change the remote endpoints that previously used the SCAN or VIPs resolved through the DNS to use the SCAN and VIPs resolved through GNS.

    For each client using a SCAN, change the SCAN that the client uses so that the client uses the SCAN in the domain delegated to GNS.

    For each client using VIP names, change the VIP name on each client so that they use the same server VIP name, but with the domain name in the domain delegated to GNS.

  8. Enter the following command as root to update the system with the SCAN name in the GNS subdomain:
    # srvctl modify scan -scanname scan_name.gns_domain

    In the preceding command syntax, gns_domain is the domain name you entered in step 3 of this procedure.

  9. Disable the static addresses once all clients are using the dynamic addresses, as follows:
    $ srvctl modify network -nettype DHCP