12.2 Installing and Configuring Sun Cluster HA for DNS

This section describes the steps used to install, configure, register, and start Sun Cluster HA for DNS. You must install and set up DNS itself and Sun Cluster before performing this procedure.

You will configure Sun Cluster HA for DNS by using the hadsconfig(1M) command. See the hadsconfig(1M) man page for details.

12.2.1 How to Install and Configure Sun Cluster HA for DNS

Once you have installed Sun Cluster and DNS, follow the procedures described in this section to install, configure, register, and activate Sun Cluster HA for DNS.

1. On each Sun Cluster server, install the SUNWscdns packages in the default location.

   If not already installed, use the pkgadd command to install the SUNWscdns package on each Sun Cluster server.

2. Run the hadsconfig(1M) command to configure Sun Cluster HA for DNS.

   The hadsconfig(1M) command is used to create, edit, and delete instances of a Sun Cluster HA for DNS data service. Refer to "12.2.2 Configuration Parameters", for information on the input you will need to supply to the hadsconfig(1M)command.

   phys-hahost1# hadsconfig

3. Set Up HA-DBMS for ORACLE7.

   HA-DBMS for ORACLE7 is required to run the HA-COMMUNITY data services.

   Follow the instructions in Chapter 5, Setting Up and Administering Sun Cluster HA for Oracle.

4. Register the Sun Cluster HA for DNS data service by running the hareg(1M) command.

   If you installed Sun Cluster HA for DNS on all potential masters of a logical host but not on all hosts in the cluster, use the -h option to specify the logical host name. Run the hareg(1M) command on only one node.

   phys-hahost1# hareg -s -r dns [-h logicalhost]

5. Use the hareg(1M) command to enable the Sun Cluster HA for DNS data service and perform a cluster reconfiguration.

   Run the hareg(1M) command on only one node.

   phys-hahost1# hareg -y dns

   The configuration is complete.

12.2.2 Configuration Parameters

This section describes the information you supply to the hadsconfig(1M) command to create configuration files Sun Cluster HA for DNS. The hadsconfig(1M) command uses templates to create these configuration files. The templates contain some default, some hardcoded, and some unspecified parameters. Accept the default values where possible. You must provide values for all parameters that are unspecified.

The fault probe parameters, in particular, can affect the performance of Sun Cluster HA for DNS. Tuning the probe interval value too low (increasing the frequency of fault probes) might encumber system performance, and also might result in false takeovers or attempted restarts when the system is simply slow.

The Sun Cluster HA for DNS data service requires you to set the takeover flag. This flag specifies how Sun Cluster will handle partial failover. There are two options:

• -y (yes) - Sun Cluster will attempt to switch over the logical host to another master, but if the attempt fails the logical host will remain on the original master.

• -n (no) - Sun Cluster will not move the logical host to another master, even if it detects problems with the data server, nor will it take any action against the sick data server or database on the logical host.

Configure the Sun Cluster HA for DNS parameters listed in the hadsconfig(1M) input form by supplying options described in Table 12-1.

Table 12-1 Configuration Parameters for Sun Cluster HA for DNS

Parameter	Description
Name of the instance	Nametag used as an identifier for the instance. The log messages generated by Sun Cluster refer to this nametag. The hadsconfig(1M) command prefixes the package name to the value you supply here. For example, if you specify "nsdns_119," hadsconfig(1M) produces "SUNWscdns_nsdns_119."
Logical host	Name of logical host that provides Sun Cluster HA for DNS service.
Configuration directory	Rooted path name specifying the directory of DNS configuration files and database on multihost disk.
Takeover flag	Specifies whether a failure of this instance will cause a takeover or failover of the logical host associated with the data service instance. Possible values are -y (yes) and -n (no).
Time between probes	The interval, in seconds, of the fault probing cycle. Accept the default value of 60 seconds.
Probe timeout	The time, in seconds, after which a fault probe will time out. The default timeout value is 60 seconds.