EMC VMAX driver does not honor cinder_emc_config_file CONF option

[Carl Pecinovsky]

The Juno EMC VMAX driver does load the "cinder_emc_config_file" option from the volume driver .conf file, but it then ignores that setting for volume operation flows, like create volume. So if I set cinder_emc_config_file to be a non-default file name, the VMAX driver won't find it and the create volume will fail.

log error:
volume-000198700498.log-20140901:2014-08-29 16:15:36.889 21351 ERROR cinder.volume.drivers.emc.emc_vmax_common [req-2f1650a4-1a80-46e1-a1f5-b6abe6a2b465 0 966dab79e18741c2b9da0bfd9361a8ea - - -] Configuration file /etc/cinder/cinder_emc_config.xml does not exist

The problem appears to be in emc_vmax_common.py --> _register_config_file_from_config_group()

        if configGroupName is None:
            self._set_ecom_credentials(CINDER_EMC_CONFIG_FILE)
            return CINDER_EMC_CONFIG_FILE
        if hasattr(self.configuration, 'cinder_emc_config_file'):
            configurationFile = self.configuration.cinder_emc_config_file
...

In this case, we are not using the cinder multi-backend support, so the configGroupName is None. It immediately sets and returns the hard-coded value:
CINDER_EMC_CONFIG_FILE = '/etc/cinder/cinder_emc_config.xml'

And it ignores the 'cinder_emc_config_file' config option setting which is checked for on the next line after the premature return. So if the configuration group name is set, then the XML file name gets loaded correctly from the option.

[Xing Yang (xing-yang)]

This works as designed. The configuration group is required. You can set it whether multiple backends is enabled or not.