2.3 Novell Cluster Services Configuration and Setup

After DNS is properly installed and configured , you must create and configure a DNS resource in Novell Cluster Services. This includes configuring DNS load and unload scripts; setting DNS Start, Failover, and Failback modes; and assigning the DNS resource to specific servers in your cluster.

2.3.1 Creating a DNS Cluster Resource

Novell Cluster Services includes a DNS resource template, which greatly simplifies the process for creating a DNS cluster resource. Much of the DNS cluster resource configuration is perfomed automatically by the DNS resource template. See Creating Cluster Resources in the OES Novell Cluster Services 1.8.1 Administration Guide for Linux for more information.

To create a DNS cluster resource:

  1. Ensure the shared disk (file system) you created and mounted in Step 1 is unmounted.

    If you used the directory names specified in the example, you can enter umount /mnt/named to unmount the shared disk.

  2. Open your Internet browser and enter the URL for iManager.

    The URL is http:// server_ip_address/nps/imanager.html. Replace server_ip_address with the IP address or DNS name of a server in the cluster or with the IP address for Apache-based services.

  3. Enter your username and password.

  4. In the left column, locate Clusters and then click Cluster Options.

    iManager displays three links under Clusters that you can use to configure and manage your cluster.

  5. Specify the cluster name, or browse and select it, then click New.

  6. Specify Resource as the resource type you want to create by clicking the Resource radio button, then click Next.

  7. Specify a name for the DNS resource.

  8. Type the DNS template name in the Inherit From Template field, or browse and select it from the list.

  9. Check the Define Additional Properties check box, click Next, and then continue with Configuring DHCP Load and Unload Scripts.

    The DNS resource template configures the DNS resource by automatically creating DNS load and unload scripts, setting failover and failback modes, and assigning DNS as a resource to all nodes in the cluster.

2.3.2 Configuring DNS Load and Unload Scripts

Load Script Configuration

The DNS load script page should already be displayed. The load script contains commands to start the DNS service. You must customize some commands for your specific DNS configuration.

The load script appears similar to the following example:

#!/bin/bash
. /opt/novell/ncs/lib/ncsfuncs
# mount the file system.
exit_on_error mount -t reiserfs /dev/evms/named /mnt/named
# add the IP address
exit_on_error add_secondary_ipaddress a.b.c.d
# start named
exit_on_error /usr/sbin/named -c /mnt/named/etc/named.conf -u named
sleep 2
exit_on_error checkproc -p /var/run/named/named.pid /usr/sbin/named
# return status
exit 0

To customize the DNS load script for your specific configuration:

  1. View and, if necessary, edit the following lines for your specific directory structure, mount point, and file system:

    exit_on_error mount -t reiserfs /dev/evms/named /mnt/named
    
    exit_on_error /usr/sbin/named -c /mnt/named/etc/named.conf -u named
    
    exit_on_error checkproc -p /var/run/named/named.pid /usr/sbin/named
    
  2. Edit the following line to assign a unique IP address to the DNS cluster resource:

    exit_on_error add_secondary_ipaddress a.b.c.d
    

    Replace a.b.c.d with the IP address you want to assign to the DNS cluster resource.

    The IP address for the DNS cluster resource allows clients to reconnect to that address regardless of which server is hosting it.

  3. Click Next and continue with the unload script configuration.

Unload Script Configuration

The DNS unload script page should now be displayed. The unload script contains commands to stop the DNS service. You must customize some commands for your specific DNS configuration.

The unload script appears similar to the following example:

#!/bin/bash
. /opt/novell/ncs/lib/ncsfuncs
# request named stop
ignore_error killproc -p /var/run/named.pid -TERM /usr/sbin/named
# stop named otherwise
sleep 8
ignore_error fuser -k /mnt/named
# del the IP address
ignore_error del_secondary_ipaddress a.b.c.d
# umount the file system
exit_on_error umount /mnt/named
# return status
exit 0
  1. View and, if necessary, edit the mount points in the applicable lines of the unload script.

  2. Replace a.b.c.d with the same IP address you specified in the load script, then click Next.

2.3.3 Setting DNS Start, Failover, and Failback Modes

The page to set Start, Failover, and Failback modes should now be displayed.

The DNS resource template sets the DNS resource Start mode and Failover mode to Auto and the Failback Mode to Disable.

If the DNS resource Start mode is set to Auto, the DNS server automatically loads on a designated server when the cluster is first brought up. If the DNS Start mode is set to Manual, you can manually start DNS on a specific server when you want, instead of having it automatically start when servers in the cluster are brought up.

If the DNS Failover mode is set to Auto, the DNS server automatically moves to the next server in the Assigned Nodes list in the event of a hardware or software failure. If the DNS Failover mode is set to Manual, you can intervene after a failure occurs and before the DNS server is started on another node.

If the DNS Failback mode is set to Disable, the DNS server will continue running on the node it has failed to. If the DNS Failback Mode is set to Auto, the DNS server automatically moves back to its preferred node when the preferred node is brought back online. Set the DNS Failback mode to Manual to prevent the DNS server from moving back to its preferred node when that node is brought back online, until you are ready to allow it to happen.

View or change the DNS resource Start, Failover, and Failback modes, then click Next and continue with View or Edit DHCP Resource Server Assignments.

2.3.4 View or Edit DNS Resource Server Assignments

The page to view or change DNS resource server assignments should now be displayed. The DNS resource template automatically assigns the DNS resource to all nodes in the cluster. The order of assignment is the order the nodes appear in the resource list.

To view or edit DNS resource node assignments or change the server failover order:

  1. From the list of unassigned nodes, select the server you want the resource assigned to, then click the Right-arrow button to move the selected server to the Assigned Nodes list.

    Repeat this step for all servers you want assigned to the resource. You can also use the Left-arrow button to unassign servers from the resource.

  2. Click the Up-arrow and Down-arrow buttons to change the failover order of the servers assigned to the resource or volume.

  3. Click Apply or Finish to save node assignment changes.