'Helper function to return the list of nodes.
If unable to connect ironic server, an empty list is returned.
:returns: a list of raw node from ironic'

def _get_node_list(self, **kwargs):

    node_list = []
    try:
        node_list = self.ironicclient.call('node.list', **kwargs)
    except exception.NovaException as e:
        LOG.error('Failed    to    get    the    list    of    nodes    from    the    Ironic    inventory.    Error:    %s', e)
    except Exception as e:
        LOG.error('An    unknown    error    has    occurred    when    trying    to    get    the    list    of    nodes    from    the    Ironic    inventory.    Error:    %s', e)
    return node_list
