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|Oracle Solaris Cluster Data Services Reference Manual Oracle Solaris Cluster 4.0|
- resource type implementation for failover Domain Name Service (DNS)
The DNS data service for Oracle Solaris Cluster is configured as a resource managed by the Oracle Solaris Cluster Resource Group Manager (RGM). You must set the following properties on a DNS resource.
See r_properties(5) for a complete description of the following resource properties.
A list of logical-hostname or shared-address network resources upon which this resource has a dependency. This list contains all network-address resources that appear in the properties Resource_dependencies, Resource_dependencies_weak, Resource_dependencies_restart, or Resource_dependencies_offline_restart.
This property is updated automatically by the RGM, based on the setting of the resource-dependencies properties. You do not set this property directly. Instead, use the Resource_dependencies property.
The empty list
Specifies a list of resources upon which a resource depends. This list includes any logical-hostname or shared-address network resources that are used by a resource. The default value for this property is null.
You can specify one or more resource names. Each network resource can contain one or more logical host names. See the clreslogicalhostname(1CL) and clressharedaddress(1CL) man pages for more information.
You can specify an alternate kind of dependency by using the Resource_dependencies_weak, Resource_dependencies_restart, or Resource_dependencies_offline_restart property instead of the Resource_dependencies property. For more information, see the r_properties(5) man page.
The empty list
For DNS resources, the value of 53/udp is the only recommended value.
Type string array. This property is the path name to the configuration directory that contains the file named.conf of the DNS resource. You must specify only one value for this property at resource creation time.
Type string array. This property is the configuration file to be used for starting DNS. The default is conf, which means that the DNS is started by using the named.conf file located in the directory pointed to by the value of the Confdir_list property. A value of boot means that DNS is started with the named.boot file as the configuration file. You can specify the value of this property at resource creation time only.
Type integer. Default is 4. The Minimum value is –1. This property controls the restarts of the fault monitor. It indicates the number of times the fault monitor is restarted by the process monitor facility and corresponds to the -n option passed to the pmfadm(1M) command. The number of restarts is counted in a specified time window (see the property Monitor_retry_interval). Note that this property refers to the restarts of the fault monitor itself, not DNS. The restarts of DNS are controlled by the system-defined properties Thorough_Probe_Interval and Retry_IntervalandRetry_Count, as specified in the description of those system-defined properties. See clresource(1CL). You can modify the value for this property any time.
Type integer. Default is 2. The Minimum value is –1. Indicates the time (in minutes) over which the failures of the fault monitor are counted and corresponds to the -t option passed to the pmfadm(1M) command. If the number of times the fault monitor fails exceeds the extension property Monitor_retry_count, the fault monitor is not restarted by the Process Monitor Facility. You can modify the value for this property any time.
Type integer. Default is 120. The Minimum value is 15. Indicates the time-out value (in seconds) used by the fault monitor to probe a DNS instance. You can modify the value for this property any time.
Example 1 Initiating a Failover DNS Resource
For this example to work, you must first install the data service. This example instantiates a failover DNS resource named dnss in a resource group named dns-rg. dns-rg is assumed to contain at least one LogicalHostname resource, which identifies the logical hostnames associated with the resource group.
example# clresourcetype register SUNW.dns example# clresource create -g dns-rg –t SUNW.dns \ -p Confdir_list=/global/dns dnss
In this example, the DNS resource created is named dnss, which listens on port 53, with a corresponding configuration directory path name /global/dns. The configuration file that is used for starting the DNS resource is named.conf, located under /global/dns.
Example 2 Instantiating a Failover DNS Resource
For this example to work, the data service must first be installed. This example instantiates a failover DNS resource named dns in a resource group named dns-rg, which uses the LogicalHostname resource lh-specific.
example# clresourcetype register SUNW.dns example# clresource create –g dns-rg –t SUNW.dns \ -p Confdir_list=/global/dns \ -p Network_resources_used=lh-specific dns-lh
In this example, the LogicalHostname resource lh-specific must be a resource in the dns-rg resource group.
See attributes(5) for descriptions of the following attributes: