Configuration Rules

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Each rule in the Configuration Rules (Config_Rules) object class specifies a program name that the Configuration Manager must execute. These programs are typically the configuration programs for the devices at the top of the nodes. When these programs are invoked, the names of the next lower-level devices that need to be configured are returned.

The Configuration Manager configures the next lower-level devices by invoking the configuration methods for those devices. In turn, those configuration methods return a list of to-be-configured device names. The process is repeated until no more device names are returned. As a result, all devices in the same node are configured in transverse order. The following are different types of rules:

  • Phase 1
  • Phase 2
  • Service

The system boot process is divided into two phases. In each phase, the Configuration Manager is invoked. During phase 1, the Configuration Manager is called with a -f flag, which specifies that phase = 1 rules are to be executed. This results in the configuration of base devices into the system, so that the root file system can be used. During phase 2, the Configuration Manager is called with a -s flag, which specifies that phase = 2 rules are to be executed. This results in the configuration of the rest of the devices into the system.

For more information on the booting process, see Understanding System Boot Processing in Operating system and device management.

The Configuration Manager invokes the programs in the order specified by the sequence value in the rule. In general, the lower the sequence number within a given phase, the higher the priority. Thus, a rule with a 2 sequence number is executed before a rule with a sequence number of 5. An exception is made for 0 sequence numbers, which indicate a don't-care condition. Any rule with a sequence number of 0 is executed last. The Configuration Rules (Config_Rules) object class provides an example of this process.

If device names are returned from the program invoked, the Configuration Manager finishes traversing the node tree before it invokes the next program. Note that some program names might not be associated with any devices, but they must be included to configure the system.