Using CA AppLogic® › Appliance Developer Guide › Appliance Kit › Appendix › CA AppLogic® Configuration File Formats › Appliance Instance Descriptor

Appliance Instance Descriptor

The instance descriptor file contains all of the data from the appliance class description (as may be seen in the editor, in the View/Edit Class dialog), modified by any attributes and property value settings applied to the instance (refer to the CA AppLogic® infrastructure editor documentation for details on how configuration is defined and propagated in applications).

Note that in all but the most advanced appliances, there is no need to access data in the appliance descriptor directly, as the application-specific configuration values are provided in processed formats, as described in the Appliance Boundary chapter.

The instance descriptor is a structured text file, with the following format:

instance main. instance-path : .class= catalog . classname

   { 
   . clsattr = value 
   .... 
   resource cpu: min= num , max= num , dflt= num 
   resource mem: min= num , max= num , dflt= num 
   resource bw: min= num , max= num , dflt= num 
   (input|output) trmname : protocol= filter , dev=eth num 
      { 
      hwaddr=' macaddr ' 
      } 
   ... 
   interface default: dev=eth num 
      { 
      hwaddr=' macaddr ' 
      ip= ipaddr 
      } 
   volume boot: dev= devfile [, class, type=(instantiable|shared)] [(mandatory|ro|shared|class), ... ] [, mount= dir ] [, disconnected] [, static] 
   volume volname : dev=.... 
   ... 
   property prpname : value= prpval , attr = val , ... 
   property ... 
   ... 
   } 

Here are the sections into which the file is divided and what they contain:

Heading

Includes the appliance's location inside the application (instance-path), reflecting the hierarchy of assemblies in which it is contained and the class from which it was created (catalog . classname). If the appliance is a singleton defined in an application, the catalog name is empty.

Class Attributes

This section contains various class attributes, with names starting with a dot. Their values are either the class default, or a value explicitly set for the appliance instance. Except where noted, each attribute corresponds to a setting in the Attributes dialog in the editor. The following attributes are available:

    .hostname= string (not user-settable, generated from the instance name) 
    .migrateable= (0|1) 
    .locked= (0|1) 
    .start_order= num 
    .boot_tout= num 
    .shutdown_tout= num 
    .field_opt= num (this is the FE code value from the Edit Class dialog for the appliance class, not affected by any setting that might be provided in the Attributes dialog) 
    .inst_field_opt= num (this is the FE code value from the Attributes dialog). 
    .restart_mode (container|self)= 

Resource Configuration

This section contains only the resource limits (as set in the application). The actual resources allocated are not visible in the instance descriptor.

Terminals

This section has one entry for each appliance terminal. It may be empty, if the appliance has no terminals. For each terminal, the following data is provided:

• terminal type (input or output)
• terminal name (trmname)
• protocol filter name (filter)
• device number (dev=ethnum). Note that this does not necessarily correspond to a valid device name (the device names are OS-dependent).
• device MAC address (macaddr)
• device IP address (ipaddr) - present only if the terminal is connected

Default Interface

This defines the configuration of the appliance's service interface (used to configure the appliance initially, and to report status to the grid controller). Includes the following data:

• device MAC address (macaddr)
• device IP address (ipaddr) - present only if the terminal is connected

Volumes

This section has one entry for each volume and has at least one entry (the boot volume of the appliance). The following is defined for each volume:

Device special file (or another OS-specific identifier of the device that this volume appears as in the appliance): devfile If the volume contains a mountable file system, this name can be used in the mount command and may refer to a device other than the physical device (e.g, it may be a 'partition device' name). Otherwise, this name refers to the actual device.

If the volume belongs to the appliance class, it has the class attribute, and the type attribute is set to one of: ( instantiable|shared|blank ).

The volume may have one or more optional attributes: (mandatory|ro|shared|class)

Volumes that are mounted, or those that have a mount point defined for them in the appliance class (even if mount for them failed) have the mount= attribute, with the name of the actual or requested mount point, as follows:

• Volumes for which the user specified a mount point in the appliance class are mounted by APK; they will have the mount point defined in the class reflected in the instance descriptor (whether APK succeeds in mounting them or not).
• Volumes that do not have a mount point specified in the class, but are mounted in the appliance by other means (for example, the boot volumes are mounted by the OS), will have the actual mount point in the mount= attribute, and also the static attribute will be set.

Optional placeholder volumes defined in the appliance, but not assigned an actual data volume will have the disconnected attribute.

Properties

One property entry is present for each property defined for the appliance class. For each property, the following is provided:

• prpval – effective value of the property for the instance. This is either the class default, or an explicitly configured value.
• attr=val – various property attributes, copied from the appliance class description (including the property type, range of valid values, and so on).