# DNS Server

> Overview
> Before Starting
> Installing Sun Cluster HA for DNS
> Customizing Sun Cluster HA for DNS

## Overview

SunPlexTM Manager uses one of the following methods to install Sun Cluster HA for Domain Name Server (DNS).

- Converting an existing DNS configuration into an HA service. The configuration file must be in a global file system.
- Setting up a simple forwarding DNS configuration as a demo.

You must configure DNS as a failover service.

For a more advanced configuration, you can manually customize your configuration after SunPlex Manager completes the installation. The
in.named
(1M) man page contains more information.

To completely customize your Sun Cluster HA for DNS installation, follow the procedures in the Sun Cluster 3.1 Data Services Installation and Configuration Guide.

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## Before Starting

Before you install the DNS package, check the following items:

- Ensure that the logical host name is set up. In most cases, you set up the logical host name when you install Sun Cluster. If the logical host name is not set up, see Creating a Logical Host Name Resource.

- If you want to use an existing DNS configuration, ensure that the configuration files are in a global directory.

- If you want to set up the simple forwarding DNS configuration, the name of a DNS server must be located on your network. You must also have a global directory available to hold the configuration file.

- Ensure that you have the CD that contains the Sun Cluster 3.1 data service.

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## Installing Sun Cluster HA for DNS

| The DNS data service takes approximately 10 minutes to install.
| When you exit SunPlex Manager or click Back in your web browser window after you begin the installation, the data service disconnects you from the installation. This disconnection can result in an incomplete installation because of insufficient information or an unresolved error message. To clean up an incomplete installation, you must remove the application files and resources and resource groups that were created.

To install DNS, complete the following steps:

1. From the navigation frame in SunPlex Manager, choose [cluster name] Cluster.

   The Cluster window appears.

2. From the Configure Data Service menu, choose DNS.

   SunPlex Manager ensures that:

   - The DNS data service packages are already installed.
   - The DNS resource type is registered with RGM.

   If the DNS data service package is installed and is registered, proceed to the next step.

   If SunPlex Manager does not find the DNS data service package already installed and registered, SunPlex Manager guides you through installation and registration. You need to provide the location of the CD that contains the Sun Cluster 3.1 data service.

   A window that contains configuration information appears.

3. Modify the information on the configuration page for your system.

   Field | Description
   --- | ---
   Network Resource | Specifies the logical host name that is used to access DNS over the network.
   Resource Name | Specifies the name of the DNS resource that is created. This name must be unique within the cluster.
   Configuration Type | If you choose "use existing," an existing DNS configuration is used. If you choose "create demo," the demonstration forwarding service is configured.
   Update /etc/resolve.conf , /etc/inet/hosts , and /etc/nsswitch.conf on each host | The files in this directory are updated for production use. Until then, you might want to leave these files unmodified.

   SunPlex Manager displays a second configuration page that prompts you to provide additional information, depending on the type of configuration that you chose.

   - If you chose "create demo," type the name of the global directory that is to hold the configuration files. Then, type the name of an existing name server that is to receive the forwarded requests.

   - If you chose "use existing," type the path to the existing configuration file. The file (the
     named.conf
     or
     named.boot
     file) must be in a global directory.

4. To install the DNS data service package by using the parameters that you have set, click Continue.

   SunPlex Manager verifies the information on the configuration page. If SunPlex Manager finds no errors, it displays a confirmation page. SunPlex Manager then asks if you want to continue. If SunPlex Manager discovers errors, it displays an error message and the configuration page.

5. To configure and start a resource, click Continue.

   SunPlex Manager lists the commands that it executes to configure and start the resource.

| Recommended step. To test the DNS server, type nslookup [name] [logical_hostname] in which [name] represents the name of a host to look up, and logical_hostname represents the logical host name that you specified in the Network Resource field in this step. If you chose the demo configuration, you can also test the hardwired host name a.b.c, which returns IP address 1.2.3.4. This test verifies that the new DNS server is responding.

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## Customizing Sun Cluster HA for DNS

Instructions about customizing your DNS installation are presented in the Sun Cluster 3.1 Data Services Installation and Configuration Guide and
in.named
(1M) man page.