A.7. Defining Custom Properties

The custom properties that are accepted by the Red Hat Virtualization Manager - and in turn passed to custom hooks - are defined using the engine-config command. Run this command as the root user on the host where Red Hat Virtualization Manager is installed.
The UserDefinedVMProperties and CustomDeviceProperties configuration keys are used to store the names of the custom properties supported. Regular expressions defining the valid values for each named custom property are also contained in these configuration keys.
Multiple custom properties are separated by a semi-colon. Note that when setting the configuration key, any existing value it contained is overwritten. When combining new and existing custom properties, all of the custom properties in the command used to set the key's value must be included.
Once the configuration key has been updated, the ovirt-engine service must be restarted for the new values to take effect.

Example A.1. Virtual Machine Properties - Defining the smartcard Custom Property

  1. Check the existing custom properties defined by the UserDefinedVMProperties configuration key using the following command:
    # engine-config -g UserDefinedVMProperties
    As shown by the output below, the custom property memory is already defined. The regular expression ^[0-9]+$ ensures that the custom property will only ever contain numeric characters.
    # engine-config -g UserDefinedVMProperties
    UserDefinedVMProperties:  version: 3.6
    UserDefinedVMProperties:  version: 4.0
    UserDefinedVMProperties : memory=^[0-9]+$ version: 4.0
  2. Because the memory custom property is already defined in the UserDefinedVMProperties configuration key, the new custom property must be appended to it. The additional custom property, smartcard, is added to the configuration key's value. The new custom property is able to hold a value of true or false.
    # engine-config -s UserDefinedVMProperties='memory=^[0-9]+$;smartcard=^(true|false)$' --cver=4.0
  3. Verify that the custom properties defined by the UserDefinedVMProperties configuration key have been updated correctly.
    # engine-config -g UserDefinedVMProperties
    UserDefinedVMProperties:  version: 3.6
    UserDefinedVMProperties:  version: 4.0
    UserDefinedVMProperties : memory=^[0-9]+$;smartcard=^(true|false)$ version: 4.0
  4. Finally, the ovirt-engine service must be restarted for the configuration change to take effect.
    # systemctl restart ovirt-engine.service

Example A.2. Device Properties - Defining the interface Custom Property

  1. Check the existing custom properties defined by the CustomDeviceProperties configuration key using the following command:
    # engine-config -g CustomDeviceProperties
    As shown by the output below, no custom properties have yet been defined.
    # engine-config -g CustomDeviceProperties
    CustomDeviceProperties:  version: 3.6
    CustomDeviceProperties:  version: 4.0
  2. The interface custom property does not already exist, so it can be appended as is. In this example, the value of the speed sub-property is set to a range of 0 to 99999, and the value of the duplex sub-property is set to a selection of either full or half.
    # engine-config -s CustomDeviceProperties="{type=interface;prop={speed=^([0-9]{1,5})$;duplex=^(full|half)$}}" --cver=4.0
  3. Verify that the custom properties defined by the CustomDeviceProperties configuration key have been updated correctly.
    # engine-config -g CustomDeviceProperties
    UserDefinedVMProperties:  version: 3.6
    UserDefinedVMProperties:  version: 4.0
    UserDefinedVMProperties : {type=interface;prop={speed=^([0-9]{1,5})$;duplex=^(full|half)$}} version: 4.0
  4. Finally, the ovirt-engine service must be restarted for the configuration change to take effect.
    # systemctl restart ovirt-engine.service