Installing DNS

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This section describes the steps to install DNS and to enable DNS to run as Oracle Solaris Cluster HA for DNS.

Oracle Solaris Cluster HA for DNS uses the Internet Domain Name Server (named) software that is bundled with the Oracle Solaris operating system. See the named (1M) man page for information about how to set up DNS. The Oracle Solaris Cluster configuration involves the following differences.

The DNS database is located on the cluster file system, not a local file system.
A network resource (relocatable IP address), not the name of a physical host, identifies the name of a DNS server.

How to Install DNS

This section describes how to install the DNS service.

On a cluster member, become an administrator that provides solaris.cluster.admin authorization.

Decide on the network resource that will provide the DNS service.
This name should be an IP address (logical hostname) that you set up when you install the Oracle Solaris Cluster software. See the Oracle Solaris Cluster 4.3 Concepts Guide document for details about network resources.

Ensure that the DNS executable (named) is in the directory /usr/sbin.
The DNS executable is bundled with the Oracle Solaris operating system. Ensure that this executable is located in the /usr/sbin directory before you begin the installation.

Create directory structure /global/dns/named on the cluster file system to hold the DNS configuration files (at level /global/dns) and database files (at level /global/dns/named).
See the Oracle Solaris Cluster 4.3 Software Installation Guide for information about configuring a cluster file systems.
```
# mkdir -p /global/dns/named
```

Place the configuration file for DNS, named.conf or named.boot, under the /global/dns directory.
If you have already installed DNS, you can copy the existing named.conf or named.boot file to the /global/dns directory. Otherwise, create a named.conf file in this directory. See the named (1M) man page for information on the types of entries to place in named.conf or named.boot. Either the named.conf file or the named.boot file must exist. Both files can exist.

Place all of the DNS database files (listed in the named.conf file) under the /global/dns/named directory.

On all of the clients of Oracle Solaris Cluster HA for DNS, create an entry for the network resource of the DNS service in the /etc/resolv.conf file.
On all of the nodes, edit the /etc/resolv.conf file to contain the network resource. The following example shows the entries for a four-node configuration (phys-schost-1, phys-schost-2, phys-schost-3, and phys-schost-4) with the logical hostname schost-1.example.com.
```
domain example.com
 
; schost-1.example.com
Only entry to be added if the file is already present.
nameserver 192.29.72.90

; phys-schost-2.example
nameserver 129.146.1.151

; phys-schost-3.example
nameserver 129.146.1.152

; phys-schost-4.example
nameserver 129.144.134.19

; phys-schost-1.example
nameserver 129.144.1.57
```
Make the network resource the first entry after the domain name. DNS attempts to use the addresses in the order that they are listed in the resolv.conf file to access the server.

Note - If the /etc/resolv.conf is already present on the nodes, just add the first entry that shows the logical hostname in the preceding example. The order of the entries determines the order in which DNS tries to access the server.

On all of the cluster nodes, edit the /etc/inet/hosts file to create an entry for the network resource of the DNS service.
In the following example, perform these steps.
- Replace the IPaddress variable with your actual IP address, such as 129.146.87.53.
- Replace the logical-hostname variable with your actual network resource (logical hostname).
```
127.0.0.1      localhost
IPaddress      logical-hostname
```

On all of the cluster nodes, ensure that the hosts entry in the /etc/nsswitch.conf file has the string dns after cluster and files.
Example:
```
hosts:    cluster files dns
```

On all of the cluster nodes, test DNS.
The following example shows how to test DNS.
```
# /usr/sbin/named -c /global/dns/named.conf
# nslookup phys-schost-1
```

On all of the cluster nodes, stop DNS.
Be sure to stop the named executable before you proceed.
```
# pkill -x named
```

Next Steps

If you installed the Oracle Solaris Cluster HA for DNS packages during your Oracle Solaris Cluster installation, go to Registering and Configuring Oracle Solaris Cluster HA for DNS. Otherwise, go to Installing the Oracle Solaris Cluster HA for DNS Package.